func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}

```swift
// Check if in given array of numbers, are any two numbers closer to each other than
// given threshold.
// hasCloseElements(numbers: [1.0, 2.0, 3.0], threshold: 0.5) == false
// hasCloseElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0], threshold: 0.3) == true
func hasCloseElements(numbers: [Double], threshold: Double) -> Bool {
    for i in 0..<numbers.count {
        for j in (i + 1)..<numbers.count {
            if abs(numbers[i] - numbers[j]) < threshold {
                return true
            }
        }
    }
    return false
}
```

func separateParenGroups(parenString: String) -> [String] {
    var result: [String] = []
    var currentGroup = ""
    var parenStack: [Character] = []
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            parenStack.append(char)
            currentGroup.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                currentGroup.append(char)
            } else {
                result.append(currentGroup)
                currentGroup = ""
            }
        } else {
            currentGroup.append(char)
        }
    }
    
    if currentGroup.count > 0 {
        result.append(currentGroup)
    }
    
    return result
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var result: [String] = []
    var currentGroup = ""
    var parenStack: [Character] = []
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            parenStack.append(char)
            currentGroup.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                currentGroup.append(char)
            } else {
                result.append(currentGroup)
                currentGroup = ""
            }
        } else {
            currentGroup.append(char)
        }
    }
    
    if currentGroup.count > 0 {
        result.append(currentGroup)
    }
    
    return result
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "()") == ["()"])
assert(separateParenGroups(parenString: "(())") == ["(())"])
assert(separateParenGroups(parenString: "()()()") == ["()", "()", "()", "()"])
assert(separateParenGroups(parenString: "()(((())))") == ["()", "(((())))"])
assert(separateParenGroups(parenString: "()()()(((())))()()()()") == ["()", "()", "()", "(((())))", "()", "()", "()", "()"])
assert(separateParenGroups(parenString: "()(((())))()()()()(((()))()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()

func separateParenGroups(parenString: String) -> [String] {
    var result: [String] = []
    var currentGroup = ""
    var parenCount = 0
    for char in parenString {
        if char == "(" {
            parenCount += 1
        } else if char == ")" {
            parenCount -= 1
        } else if char == " " && parenCount == 0 {
            result.append(currentGroup)
            currentGroup = ""
        } else {
            currentGroup.append(char)
        }
    }
    result.append(currentGroup)
    return result
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var result: [String] = []
    var currentGroup = ""
    var parenCount = 0
    for char in parenString {
        if char == "(" {
            parenCount += 1
        } else if char == ")" {
            parenCount -= 1
        } else if char == " " && parenCount == 0 {
            result.append(currentGroup)
            currentGroup = ""
        } else {
            currentGroup.append(char)
        }
    }
    result.append(currentGroup)
    return result
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "()()()") == ["()()()"])
assert(separateParenGroups(parenString: "()(((()))())()") == ["()(((()))())()"])
assert(separateParenGroups(parenString: "()(((()))())()()") == ["()(((()))())()()", "()()()"])
assert(separateParenGroups(parenString: "()(((()))())()()()(())()()()") == ["()(((()))())()()", "()()()"])
assert(separateParenGroups(parenString: "()(((()))())()()()(((()))()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()


//: [Next](@next)

func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var currentGroup = ""
    var parenCount = 0
    for char in parenString {
        if char == "(" {
            parenCount += 1
        } else if char == ")" {
            parenCount -= 1
        } else if char == " " {
            continue
        }
        currentGroup += String(char)
        if parenCount == 0 {
            result.append(currentGroup)
            currentGroup = ""
        }
    }
    return result
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var currentGroup = ""
    var parenCount = 0
    for char in parenString {
        if char == "(" {
            parenCount += 1
        } else if char == ")" {
            parenCount -= 1
        } else if char == " " {
            continue
        }
        currentGroup += String(char)
        if parenCount == 0 {
            result.append(currentGroup)
            currentGroup = ""
        }
    }
    return result
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "((()))") == ["((()))"])
assert(separateParenGroups(parenString: "()()()") == ["()()()", "()()()"])
assert(separateParenGroups(parenString: "()((()())") == ["()((()()", "()((()()"])
assert(separateParenGroups(parenString: "()()(((()())") == ["()()(((()()", "()()(((()()"])
assert(separateParenGroups(parenString: "()()(((()())()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()

func separateParenGroups(parenString: String) -> [String] {
    var result: [String] = []
    var currentGroup: String = ""
    var parenStack: [Character] = []
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            parenStack.append(char)
            currentGroup.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                currentGroup.append(char)
            } else {
                result.append(currentGroup)
                currentGroup = ""
            }
        } else {
            currentGroup.append(char)
        }
    }
    
    if currentGroup.count > 0 {
        result.append(currentGroup)
    }
    
    return result
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var result: [String] = []
    var currentGroup: String = ""
    var parenStack: [Character] = []
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            parenStack.append(char)
            currentGroup.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                currentGroup.append(char)
            } else {
                result.append(currentGroup)
                currentGroup = ""
            }
        } else {
            currentGroup.append(char)
        }
    }
    
    if currentGroup.count > 0 {
        result.append(currentGroup)
    }
    
    return result
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "( ( ( a ) ) )") == ["( ( ( a ) ) )"])
assert(separateParenGroups(parenString: "a ( b ) ( c ) d ( e ) f") == ["a ( b ) ( c )", "d ( e ) f"])
assert(separateParenGroups(parenString: "a ( b ( c ) d ( e ) f ) g") == ["a ( b ( c ) d ( e ) f )", "g"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ( e ( f ) g ) h ) i ) j ) k") == ["a ( b ( c ( d ( e ( f ) g ) h ) i ) j )", "k"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l )") == ["a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l )"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l ) m ( n ( o ( p ) q ) r ) s") == ["a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l )", "m ( n ( o ( p ) q ) r )", "s"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l ) m ( n ( o ( p ) q ) r ) s ( t ( u ( v ) w ) x ) y") == ["a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l )", "m ( n ( o ( p ) q ) r )", "s ( t ( u ( v ) w ) x )", "y"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l ) m ( n ( o ( p ) q ) r ) s ( t ( u ( v ) w ) x ) y z") == ["a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l )", "m ( n ( o ( p ) q ) r )", "s ( t ( u ( v ) w ) x )", "y", "z"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l ) m ( n ( o ( p ) q ) r ) s ( t ( u ( v ) w ) x ) y z ( a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l ) m ( n ( o ( p ) q ) r ) s ( t ( u ( v ) w ) x ) y )") == ["a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l )", "m ( n ( o ( p ) q ) r )", "s ( t ( u ( v ) w ) x )", "y", "z", "a ( b ( c ( d ( e ( f ( g ) h ) i ) j ) k ) l )", "m ( n ( o ( p ) q ) r )", "s ( t ( u ( v ) w ) x )", "y"])
assert(separ

func separateParenGroups(parenString: String) -> [String] {
    var parenStack = [Character]()
    var parenGroups = [String]()
    
    for char in parenString {
        if char == "(" {
            parenStack.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
            } else {
                parenGroups.append("()")
            }
        } else {
            parenGroups.append("\(char)")
        }
    }
    
    return parenGroups
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var parenStack = [Character]()
    var parenGroups = [String]()
    
    for char in parenString {
        if char == "(" {
            parenStack.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
            } else {
                parenGroups.append("()")
            }
        } else {
            parenGroups.append("\(char)")
        }
    }
    
    return parenGroups
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "((()))") == ["((()))"])
assert(separateParenGroups(parenString: "()()()") == ["()()()", "()()()"])
assert(separateParenGroups(parenString: "()((())") == ["()((())"])
assert(separateParenGroups(parenString: "()()()()()") == ["()()()()()"])
assert(separateParenGroups(parenString: "()()(((()))()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()")OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var currentGroup = ""
    var parenCount = 0
    
    for char in parenString {
        if char == "(" {
            parenCount += 1
        } else if char == ")" {
            parenCount -= 1
        } else if char == " " {
            continue
        } else {
            currentGroup += String(char)
        }
        
        if parenCount == 0 {
            result.append(currentGroup)
            currentGroup = ""
        }
    }
    
    return result
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var currentGroup = ""
    var parenCount = 0
    
    for char in parenString {
        if char == "(" {
            parenCount += 1
        } else if char == ")" {
            parenCount -= 1
        } else if char == " " {
            continue
        } else {
            currentGroup += String(char)
        }
        
        if parenCount == 0 {
            result.append(currentGroup)
            currentGroup = ""
        }
    }
    
    return result
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "( ( ( ) ) )") == ["( ( ( ) ) )"])
assert(separateParenGroups(parenString: "()()()") == ["()()", "()()()"])
assert(separateParenGroups(parenString: "()(((()))()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()

func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var currentGroup = ""
    var parenStack = [Character]()
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            parenStack.append(char)
            currentGroup.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                currentGroup.append(char)
            } else {
                result.append(currentGroup)
                currentGroup = ""
            }
        } else {
            currentGroup.append(char)
        }
    }
    
    result.append(currentGroup)
    
    return result
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var currentGroup = ""
    var parenStack = [Character]()
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            parenStack.append(char)
            currentGroup.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                currentGroup.append(char)
            } else {
                result.append(currentGroup)
                currentGroup = ""
            }
        } else {
            currentGroup.append(char)
        }
    }
    
    result.append(currentGroup)
    
    return result
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "( ( ( ) ) )") == ["((())"])
assert(separateParenGroups(parenString: "()()()") == ["()","()","()"])
assert(separateParenGroups(parenString: "()(((()))())()") == ["()(((()))())()", "()()"])
assert(separateParenGroups(parenString: "()(((()))())()()") == ["()(((()))())()", "()()"])
assert(separateParenGroups(parenString: "()(((()))())()()()(())()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()


//: [Next](@next)

func separateParenGroups(parenString: String) -> [String] {
    var parenStack: [Character] = []
    var parenGroup: [Character] = []
    var parenGroups: [String] = []
    
    for paren in parenString {
        if paren == " " {
            continue
        }
        if paren == "(" {
            parenStack.append(paren)
            parenGroup.append(paren)
        } else if paren == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                parenGroup.append(paren)
            } else {
                parenGroups.append(String(parenGroup))
                parenGroup = []
            }
        }
    }
    if parenGroup.count > 0 {
        parenGroups.append(String(parenGroup))
    }
    return parenGroups
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var parenStack: [Character] = []
    var parenGroup: [Character] = []
    var parenGroups: [String] = []
    
    for paren in parenString {
        if paren == " " {
            continue
        }
        if paren == "(" {
            parenStack.append(paren)
            parenGroup.append(paren)
        } else if paren == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                parenGroup.append(paren)
            } else {
                parenGroups.append(String(parenGroup))
                parenGroup = []
            }
        }
    }
    if parenGroup.count > 0 {
        parenGroups.append(String(parenGroup))
    }
    return parenGroups
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "( ( ( ) ) )") == ["((())"])
assert(separateParenGroups(parenString: "()") == [""])
assert(separateParenGroups(parenString: "( ( ( ( () () ) ) ) )") == ["((())", "()()()"])
assert(separateParenGroups(parenString: "()()()") == ["()()()"])
assert(separateParenGroups(parenString: "()((())()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()


//: [Next](@next)

func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var stack = [Character]()
    var currentGroup = ""
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            stack.append(char)
            currentGroup.append(char)
        } else if char == ")" {
            if stack.count > 0 {
                stack.removeLast()
                currentGroup.append(char)
            } else {
                result.append(currentGroup)
                currentGroup = ""
            }
        } else {
            currentGroup.append(char)
        }
    }
    
    result.append(currentGroup)
    return result
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var stack = [Character]()
    var currentGroup = ""
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            stack.append(char)
            currentGroup.append(char)
        } else if char == ")" {
            if stack.count > 0 {
                stack.removeLast()
                currentGroup.append(char)
            } else {
                result.append(currentGroup)
                currentGroup = ""
            }
        } else {
            currentGroup.append(char)
        }
    }
    
    result.append(currentGroup)
    return result
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "( ( ( a ) ) ( b ) )") == [ "( ( ( a ) ) ( b ) )" ])
assert(separateParenGroups(parenString: "a ( b ) ( c ) d ( e ) f") == ["a ( b ) ( c )", "d ( e ) f"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ) e ) f ) g") == ["a ( b ( c ( d ) e ) f )", "g"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ) e ) f ( g ( h ) i ) ) j") == ["a ( b ( c ( d ) e ) f ( g ( h ) i ) )", "j"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ) e ) f ( g ( h ) i ) ) j ( k ( l ) m )") == ["a ( b ( c ( d ) e ) f ( g ( h ) i ) )", "j ( k ( l ) m )"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ) e ) f ( g ( h ) i ) ) j ( k ( l ) m ) n") == ["a ( b ( c ( d ) e ) f ( g ( h ) i ) )", "j ( k ( l ) m )", "n"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ) e ) f ( g ( h ) i ) ) j ( k ( l ) m ) n ( o ( p ) q )") == ["a ( b ( c ( d ) e ) f ( g ( h ) i ) )", "j ( k ( l ) m )", "n ( o ( p ) q )"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ) e ) f ( g ( h ) i ) ) j ( k ( l ) m ) n ( o ( p ) q ) r") == ["a ( b ( c ( d ) e ) f ( g ( h ) i ) )", "j ( k ( l ) m )", "n ( o ( p ) q )", "r"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ) e ) f ( g ( h ) i ) ) j ( k ( l ) m ) n ( o ( p ) q ) r ( s ( t ) u ) v") == ["a ( b ( c ( d ) e ) f ( g ( h ) i ) )", "j ( k ( l ) m )", "n ( o ( p ) q )", "r ( s ( t ) u )", "v"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ) e ) f ( g ( h ) i ) ) j ( k ( l ) m ) n ( o ( p ) q ) r ( s ( t ) u ) v ( w ( x ) y ) z") == ["a ( b ( c ( d ) e ) f ( g ( h ) i ) )", "j ( k ( l ) m )", "n ( o ( p ) q )", "r ( s ( t ) u )", "v ( w ( x ) y )", "z"])
assert(separateParenGroups(parenString: "a ( b ( c ( d ) e ) f ( g ( h ) i ) ) j ( k ( l ) m ) n ( o ( p ) q ) r ( s ( t ) u ) v ( w ( x ) y ) z ( a ( b ( c ( d ) e ) f ( g ( h ) i )

func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var currentGroup = ""
    var parenStack = [Character]()
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            parenStack.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
            } else {
                currentGroup += String(char)
            }
        } else {
            currentGroup += String(char)
        }
        
        if parenStack.count == 0 {
            result.append(currentGroup)
            currentGroup = ""
        }
    }
    
    return result
}

```swift
// Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
// separate those group into separate strings and return the array of those.
// Separate groups are balanced (each open brace is properly closed) and not nested within each other
// Ignore any spaces in the input string.
// separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"]
func separateParenGroups(parenString: String) -> [String] {
    var result = [String]()
    var currentGroup = ""
    var parenStack = [Character]()
    
    for char in parenString {
        if char == " " {
            continue
        }
        
        if char == "(" {
            parenStack.append(char)
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
            } else {
                currentGroup += String(char)
            }
        } else {
            currentGroup += String(char)
        }
        
        if parenStack.count == 0 {
            result.append(currentGroup)
            currentGroup = ""
        }
    }
    
    return result
}

// Test cases
assert(separateParenGroups(parenString: "( ) (( )) (( )( ))") == ["()", "(())", "(()())"])
assert(separateParenGroups(parenString: "((()))") == ["((()))"])
assert(separateParenGroups(parenString: "()()()") == ["()()()"])
assert(separateParenGroups(parenString: "()((()())") == ["()((()()", "()((()()"])
assert(separateParenGroups(parenString: "()((()())") == ["()((()()", "()((()()"])
assert(separateParenGroups(parenString: "()((()())()()()()") == ["()((()()", "()((()()"])
assert(separateParenGroups(parenString: "()((()())()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()()

func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(_ number: Float) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt128) -> Double {
    return Double(number) - Double(Int(number))
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: Float) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt128) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into

func truncateNumber(number: Double) -> Double {
    return number - floor(number)
}

func truncateNumber(number: Int) -> Double {
    return Double(number) - floor(Double(number))
}

func truncateNumber(_ number: Int) -> Double {
    return Double(number) - floor(Double(number))
}

func truncateNumber(_ number: Double) -> Double {
    return number - floor(number)
}

func truncateNumber(_ number: Float) -> Double {
    return Double(number) - floor(Double(number))
}

func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - floor(Double(number))
}

func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - floor(Double(number))
}

func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - floor(Double(number))
}

func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - floor(Double(number))
}

func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - floor(Double(number))
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - floor(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(number: Int) -> Double {
    return Double(number) - floor(Double(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(_ number: Int) -> Double {
    return Double(number) - floor(Double(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(_ number: Double) -> Double {
    return number - floor(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(_ number: Float) -> Double {
    return Double(number) - floor(Double(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - floor(Double(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - floor(Double(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - floor(Double(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - floor(Double(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - floor(Double(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 0.5
func truncateNumber(_ number: UInt128) -> Double {
    return Double(number) - floor(Double(number))

func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

func nextSmallestPalindrome(number: Int) -> Int {
    let numberString = String(number)
    let reversedString = String(numberString.characters.reverse())
    let reversedPlusNumber = numberString + reversedString
    let plusOne = Int(reversedPlusNumber)! + 1
    let plusOneString = String(plusOne)
    let plusOneReversed = String(plusOneString.characters.reverse())
    let plusOneReversedPlusNumber = plusOneString + plusOneReversed
    return Int(plusOneReversedPlusNumber)!
}

func nextLargestPalindrome(number: Int) -> Int {
    let numberString = String(number)
    let reversedString = String(numberString.characters.reverse())
    let reversedPlusNumber = numberString + reversedString
    return Int(reversedPlusNumber)!
}

func digits(number: Int) -> Int {
    return String(number).characters.count
}

func sumDigits(number: Int) -> Int {
    var sum = 0
    let numberString = String(number)
    for character in numberString.characters {
        sum += Int(String(character))!
    }
    return sum
}

func sumSquaredDigits(number: Int) -> Int {
    var sum = 0
    let numberString = String(number)
    for character in numberString.characters {
        let digit = Int(String(character))!
        sum += digit * digit
    }
    return sum
}

func difference(number: Int) -> Int {
    return sumDigits(number) - sumSquaredDigits(number)
}

func isPalindrome(number: Int) -> Bool {
    let numberString = String(number)
    let reversedString = String(numberString.characters.reverse())
    return numberString == reversedString
}

func isPrime(number: Int) -> Bool {
    if number <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(number))) {
        if number % i == 0 {
            return false
        }
    }
    return true
}

func nextPrime(number: Int) -> Int {
    var nextPrime = number
    while true {
        nextPrime += 1
        if isPrime(nextPrime) {
            return nextPrime
        }
    }
}

func previousPrime(number: Int) -> Int {
    var previousPrime = number
    while true {
        previousPrime -= 1
        if isPrime(previousPrime) {
            return previousPrime
        }
    }
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive integer, return the next smallest palindrome.
// nextSmallestPalindrome(123) == 121
// nextSmallestPalindrome(100) == 909
func nextSmallestPalindrome(number: Int) -> Int {
    let numberString = String(number)
    let reversedString = String(numberString.characters.reverse())
    let reversedPlusNumber = numberString + reversedString
    let plusOne = Int(reversedPlusNumber)! + 1
    let plusOneString = String(plusOne)
    let plusOneReversed = String(plusOneString.characters.reverse())
    let plusOneReversedPlusNumber = plusOneString + plusOneReversed
    return Int(plusOneReversedPlusNumber)!
}

// Given a positive integer, return the next largest palindrome.
// nextLargestPalindrome(123) == 321
// nextLargestPalindrome(100) == 999
func nextLargestPalindrome(number: Int) -> Int {
    let numberString = String(number)
    let reversedString = String(numberString.characters.reverse())
    let reversedPlusNumber = numberString + reversedString
    return Int(reversedPlusNumber)!
}

// Given a positive integer, return the number of digits in it.
// digits(123) == 3
// digits(100) == 2
func digits(number: Int) -> Int {
    return String(number).characters.count
}

// Given a positive integer, return the sum of its digits.
// sumDigits(123) == 6
// sumDigits(100) == 1
func sumDigits(number: Int) -> Int {
    var sum = 0
    let numberString = String(number)
    for character in numberString.characters {
        sum += Int(String(character))!
    }
    return sum
}

// Given a positive integer, return the sum of its digits squared.
// sumSquaredDigits(123) == 14
// sumSquaredDigits(100) == 100
func sumSquaredDigits(number: Int) -> Int {
    var sum = 0
    let numberString = String(number)
    for character in numberString.characters {
        let digit = Int(String(character))!
        sum += digit * digit
    }
    return sum
}

// Given a positive integer, return the difference between the sum of its
// digits and the sum of its squared digits.
// difference(123) == 6
// difference(100) == 2
func difference(number: Int) -> Int {
    return sumDigits(number) - sumSquaredDigits(number)
}

// Given a positive integer, return true if it is a palindrome.
// isPalindrome(121) == true
// isPalindrome(123) == false
func isPalindrome(number: Int) -> Bool {
    let numberString = String(number)
    let reversedString = String(numberString.characters.reverse())
    return numberString == reversedString
}

// Given a positive integer, return true if it is a prime number.
// isPrime(1) == false
// isPrime(2) == true
// isPrime(4) == false
func isPrime(number: Int) -> Bool {
    if number <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(number))) {
        if number % i == 0 {
            return false
        }
    }
    return true
}

// Given a positive integer, return the next prime number.
// nextPrime(1) == 2
// nextPrime(2) == 3
// nextPrime(4) == 5
func nextPrime(number: Int) -> Int {
    var nextPrime = number
    while true {
        nextPrime += 1
        if isPrime(nextPrime) {
            return nextPrime
        }
    }
}

// Given a positive integer, return the previous prime number.
// previousPrime(1) == 1
// previousPrime(2) == 1
// previousPrime(3) == 2
func previousPrime(number: Int) -> Int {
    var previousPrime = number
    while true {
        previousPrime -= 1
        if isPrime(previousPrime) {
            return previousPrime
        }
    }
}

// Given a positive integer

func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(number: Double) -> Int {
    return Int(number)
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncate

func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(_ number: Float) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt128) -> Double {
    return Double(number) - Double(Int(number))
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: Float) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt128) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into

func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(number: Double) -> Int {
    return Int(number)
}

func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(number)
}

func truncateNumber(number: Int) -> Int {
    return number
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(number: Int) -> Int {
    return number

func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(_ number: Float) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt128) -> Double {
    return Double(number) - Double(Int(number))
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: Float) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 35) == 5
func truncateNumber(_ number: UInt128) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into

func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(number: Double) -> Int {
    return Int(number)
}

func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(number)
}

func truncateNumber(number: Int) -> Int {
    return number
}

func truncateNumber(_ number: Int) -> Int {
    return number
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number)

func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(number: Double) -> Int {
    return Int(number)
}

func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(number)
}

func truncateNumber(number: Int) -> Int {
    return number
}

func truncateNumber(_ number: Int) -> Int {
    return number
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3.5) == 3
func truncateNumber(number: Double) -> Int {
    return Int(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(number)
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the integer part of the number.
// truncateNumber(number: 3) == 3
func truncateNumber(_ number: Int) -> Int {
    return number
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number)

func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: Double) -> Double {
    return number - Double(Int(number))
}

func truncateNumber(_ number: Float) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - Double(Int(number))
}

func truncateNumber(_ number: UInt128) -> Double {
    return Double(number) - Double(Int(number))
}

```swift
// Given a positive floating point number, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3.5) == 0.5
func truncateNumber(number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(_ number: Int) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(_ number: Double) -> Double {
    return number - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(_ number: Float) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(_ number: UInt) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(_ number: UInt8) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(_ number: UInt16) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(_ number: UInt32) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(_ number: UInt64) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller than given number) and decimals
// (leftover part always smaller than 1).
// Return the decimal part of the number.
// truncateNumber(number: 3) == 0
func truncateNumber(_ number: UInt128) -> Double {
    return Double(number) - Double(Int(number))
}

// Given a positive integer, it can be decomposed into
// and integer part (largest integer smaller

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 10, 100, 1000]) == 999
func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 10, 100, 1000]) == 999
func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 10, 100, 1000]) == 999
func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 10, 100, 1000]) == 999
func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 10, 100, 1000]) == 999
func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 10, 100, 1000]) == 999
func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 10, 100, 1000]) == 999
func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 10, 100, 1000]) == 999
func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 10, 100, 1000]) == 999
func difference(array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
//

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func difference(array: [Int]) -> Int {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return max - min
}

func sum(array: [Int]) -> Int {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return min + max
}

func product(array: [Int]) -> Int {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return min * max
}

func average(array: [Int]) -> Double {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return Double(max - min) / Double(array.count)
}

func averageSum(array: [Int]) -> Double {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return Double(min + max) / Double(array.count)
}

func squareAverage(array: [Int]) -> Double {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return Double((max - min) * (max - min)) / Double(array.count)
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// difference([1, 2, 3]) == 2
// difference([5, 2, 1, 8, 3]) == 7
func difference(array: [Int]) -> Int {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return max - min
}

// You're given an array of integers. Your task is to return the sum of the largest and smallest
// numbers in the array.
// sum([1, 2, 3]) == 6
// sum([5, 2, 1, 8, 3]) == 14
func sum(array: [Int]) -> Int {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return min + max
}

// You're given an array of integers. Your task is to return the product of the largest and smallest
// numbers in the array.
// product([1, 2, 3]) == 6
// product([5, 2, 1, 8, 3]) == 40
func product(array: [Int]) -> Int {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return min * max
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers divided by the length of the array.
// average([1, 2, 3]) == 2/3
// average([5, 2, 1, 8, 3]) == 11/5
func average(array: [Int]) -> Double {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return Double(max - min) / Double(array.count)
}

// You're given an array of integers. Your task is to return the sum of the largest and smallest
// numbers divided by the length of the array.
// averageSum([1, 2, 3]) == 2/3
// averageSum([5, 2, 1, 8, 3]) == 11/5
func averageSum(array: [Int]) -> Double {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return Double(min + max) / Double(array.count)
}

// You're given an array of integers. Your task is to return the difference between the largest and
// smallest numbers squared and divided by the length of the array.
// squareAverage([1, 2, 3]) == 2/3
// squareAverage([5, 2, 1, 8, 3]) == 11/5
func squareAverage(array: [Int]) -> Double {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return Double((max - min) * (max - min)) / Double(array.count)
}

// You're given an array of integers. Your task is to return the sum of the largest and smallest
// numbers squared and divided by the length of the array.
// squareSum([1, 2, 3]) == 2/3
// squareSum([5, 2, 1, 8, 3]) == 11/5
func squareSum(array: [Int]) -> Double {
    var min = Int.max
    var max = Int.min
    for element in array {
        if element < min {
            min = element
        }

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func difference(array: [Int]) -> Int {
    var min = Int.max
    var max = Int.min
    for number in array {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return max - min
}

func average(array: [Int]) -> Double {
    var min = Int.max
    var max = Int.min
    for number in array {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return Double(max - min) / Double(array.count)
}

func greaterAverage(array: [Int]) -> Int {
    var count = 0
    let average = average(array: array)
    for number in array {
        if number > average {
            count += 1
        }
    }
    return count
}

func lessAverage(array: [Int]) -> Int {
    return array.count - greaterAverage(array: array)
}

func divisibleByThree(array: [Int]) -> Int {
    var count = 0
    for number in array {
        if number % 3 == 0 {
            count += 1
        }
    }
    return count
}

func sumDivisibleByThree(array: [Int]) -> Int {
    var sum = 0
    for number in array {
        if number % 3 == 0 {
            sum += number
        }
    }
    return sum
}

func countDivisibleByThree(array: [Int]) -> Int {
    var count = 0
    for number in array {
        if number % 3 == 0 {
            count += 1
        }
    }
    return count
}

func sumDivisibleByFive(array: [Int]) -> Int {
    var sum = 0
    for number in array {
        if number % 5 == 0 {
            sum += number
        }
    }
    return sum
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You're given an array of integers. Your task is to return the difference between the largest
// and smallest numbers in the array.
// difference([1, 2, 3]) == 2
// difference([5, 2, 3, 1]) == 4
func difference(array: [Int]) -> Int {
    var min = Int.max
    var max = Int.min
    for number in array {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return max - min
}

// You're given an array of integers. Your task is to return the difference between the largest
// and smallest numbers divided by the length of the array.
// average([1, 2, 3]) == 2/3
// average([5, 2, 3, 1]) == 4/4
func average(array: [Int]) -> Double {
    var min = Int.max
    var max = Int.min
    for number in array {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return Double(max - min) / Double(array.count)
}

// You're given an array of integers. Your task is to return the number of values that are
// greater than the average value.
// greaterAverage([1, 2, 3]) == 0
// greaterAverage([5, 2, 3, 1]) == 2
func greaterAverage(array: [Int]) -> Int {
    var count = 0
    let average = average(array: array)
    for number in array {
        if number > average {
            count += 1
        }
    }
    return count
}

// You're given an array of integers. Your task is to return the number of values that are
// less than the average value.
// lessAverage([1, 2, 3]) == 3
// lessAverage([5, 2, 3, 1]) == 1
func lessAverage(array: [Int]) -> Int {
    return array.count - greaterAverage(array: array)
}

// You're given an array of integers. Your task is to return the number of values that are
// divisible by 3.
// divisibleByThree([1, 2, 3]) == 0
// divisibleByThree([3, 6, 9]) == 1
func divisibleByThree(array: [Int]) -> Int {
    var count = 0
    for number in array {
        if number % 3 == 0 {
            count += 1
        }
    }
    return count
}

// You're given an array of integers. Your task is to return the sum of the values that are
// divisible by 3.
// sumDivisibleByThree([1, 2, 3]) == 0
// sumDivisibleByThree([3, 6, 9]) == 18
func sumDivisibleByThree(array: [Int]) -> Int {
    var sum = 0
    for number in array {
        if number % 3 == 0 {
            sum += number
        }
    }
    return sum
}

// You're given an array of integers. Your task is to return the number of values that are
// divisible by 3.
// countDivisibleByThree([1, 2, 3]) == 0
// countDivisibleByThree([3, 6, 9]) == 1
func countDivisibleByThree(array: [Int]) -> Int {
    var count = 0
    for number in array {
        if number % 3 == 0 {
            count += 1
        }
    }
    return count
}

// You're given an array of integers. Your task is to return the sum of the values that are
// divisible by 3.
// sumDivisibleByThree([1, 2, 3]) == 0
// sumDivisibleByThree([3, 6, 9]) == 18
func sumDivisibleByFive(array: [Int]) -> Int {
    var sum = 0
    for number in array {
        if number % 5 == 0 {
            sum += number
        }
    }
    return sum
}

// You're

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func countChange(numbers: [Int]) -> [Int] {
    var result = [0, 0]
    for number in numbers {
        if number > result[0] {
            result[1] += 1
        } else if number < result[0] {
            result[1] += 1
            result[0] = number
        }
    }
    return result
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You're given an array of numbers. Your task is to return an array that contains the count of
// numbers that are bigger than the previous element, and the count of numbers that are smaller than
// the previous element. The first element should be a count of 0.
// countChange([1, 2, 3, 4, 5]) == [0, 1, 1, 2, 3]
// countChange([5, 4, 3, 2, 1]) == [1, 0, 0, 0, 0]
func countChange(numbers: [Int]) -> [Int] {
    var result = [0, 0]
    for number in numbers {
        if number > result[0] {
            result[1] += 1
        } else if number < result[0] {
            result[1] += 1
            result[0] = number
        }
    }
    return result
}

// You're given an array of numbers. Your task is to return an array that contains the count of
// numbers that are bigger than the previous element, and the count of numbers that are smaller than
// the previous element. The first element should be a count of 0.
// countChange([1, 2, 3, 4, 5]) == [0, 1, 1, 2, 3]
// countChange([5, 4, 3, 2, 1]) == [1, 0, 0, 0, 0]
func countChange(numbers: [Int]) -> [Int] {
    var result = [0, 0]
    for number in numbers {
        if number > result[0] {
            result[1] += 1
        } else if number < result[0] {
            result[1] += 1
            result[0] = number
        }
    }
    return result
}

// You're given an array of numbers. Your task is to return an array that contains the count of
// numbers that are bigger than the previous element, and the count of numbers that are smaller than
// the previous element. The first element should be a count of 0.
// countChange([1, 2, 3, 4, 5]) == [0, 1, 1, 2, 3]
// countChange([5, 4, 3, 2, 1]) == [1, 0, 0, 0, 0]
func countChange(numbers: [Int]) -> [Int] {
    var result = [0, 0]
    for number in numbers {
        if number > result[0] {
            result[1] += 1
        } else if number < result[0] {
            result[1] += 1
            result[0] = number
        }
    }
    return result
}

// You're given an array of numbers. Your task is to return an array that contains the count of
// numbers that are bigger than the previous element, and the count of numbers that are smaller than
// the previous element. The first element should be a count of 0.
// countChange([1, 2, 3, 4, 5]) == [0, 1, 1, 2, 3]
// countChange([5, 4, 3, 2, 1]) == [1, 0, 0, 0, 0]
func countChange(numbers: [Int]) -> [Int] {
    var result = [0, 0]
    for number in numbers {
        if number > result[0] {
            result[1] += 1
        } else if number < result[0] {
            result[1] += 1
            result[0] = number
        }
    }
    return result
}

// You're given an array of numbers. Your task is to return an array that contains the count of
// numbers that are bigger than the previous element, and the count of numbers that are smaller than
// the previous element. The first element should be a count of 0.
// countChange([1, 2, 3, 4, 5]) == [0, 1, 1, 2, 3]
// countChange([5, 4, 3, 2, 1]) == [1, 0, 0, 0, 0]
func countChange(numbers:

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func difference(array: [Int]) -> Int {
    var min = array[0]
    var max = array[0]
    for number in array {
        if number > max {
            max = number
        } else if number < min {
            min = number
        }
    }
    return max - min
}

func sumAndDifference(array: [Int]) -> (Int, Int) {
    var min = array[0]
    var max = array[0]
    for number in array {
        if number > max {
            max = number
        } else if number < min {
            min = number
        }
    }
    return (min + max, max - min)
}

func countZerosAndOnes(array: [Int]) -> Int {
    var zeros = 0
    var ones = 0
    for element in array {
        if element == 0 {
            zeros += 1
        } else {
            ones += 1
        }
    }
    return zeros == ones? array.count : 0
}

func countZerosAndOnesExcludingSelf(array: [Int]) -> Int {
    var zeros = 0
    var ones = 0
    var result = 0
    for element in array {
        if element == 0 {
            zeros += 1
        } else {
            ones += 1
        }
        if zeros!= ones {
            result += 1
        }
    }
    return result
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You're given an array of integers. Your task is to return the difference between the largest
// and smallest numbers in the array.
// difference([5, 2, 7, 1, 9]) == 8
// difference([1, 2, 3, 4, 5]) == 4
func difference(array: [Int]) -> Int {
    var min = array[0]
    var max = array[0]
    for number in array {
        if number > max {
            max = number
        } else if number < min {
            min = number
        }
    }
    return max - min
}

// You're given an array of integers. Your task is to return the sum of the largest and smallest
// numbers, and the difference between the largest and smallest numbers.
// sumAndDifference([5, 2, 7, 1, 9]) == (19, 8)
// sumAndDifference([1, 2, 3, 4, 5]) == (15, 4)
func sumAndDifference(array: [Int]) -> (Int, Int) {
    var min = array[0]
    var max = array[0]
    for number in array {
        if number > max {
            max = number
        } else if number < min {
            min = number
        }
    }
    return (min + max, max - min)
}

// You're given an array of integers. Your task is to return the number of subarrays that have an
// equal number of 0s and 1s.
// countZerosAndOnes([0, 1, 1, 0, 1]) == 4
// countZerosAndOnes([1, 1, 1, 1, 1]) == 0
func countZerosAndOnes(array: [Int]) -> Int {
    var zeros = 0
    var ones = 0
    for element in array {
        if element == 0 {
            zeros += 1
        } else {
            ones += 1
        }
    }
    return zeros == ones? array.count : 0
}

// You're given an array of integers. Your task is to return the number of subarrays that have an
// equal number of 0s and 1s, excluding subarrays where the number of 0s and 1s are the same.
// countZerosAndOnesExcludingSelf([0, 1, 1, 0, 1]) == 3
// countZerosAndOnesExcludingSelf([1, 1, 1, 1, 1]) == 0
func countZerosAndOnesExcludingSelf(array: [Int]) -> Int {
    var zeros = 0
    var ones = 0
    var result = 0
    for element in array {
        if element == 0 {
            zeros += 1
        } else {
            ones += 1
        }
        if zeros!= ones {
            result += 1
        }
    }
    return result
}

// You're given an array of integers. Your task is to return the number of subarrays that have an
// equal number of 0s and 1s, excluding subarrays where the number of 0s and 1s are the same.
// countZerosAndOnesExcludingSelf([0, 1, 1, 0, 1]) == 3
// countZerosAndOnesExcludingSelf([1, 1, 1, 1, 1]) == 0
func countZerosAndOnesExcludingSelf(array: [Int]) -> Int {
    var zeros = 0
    var ones = 0
    var result = 0
    for element in array {
        if element == 0 {
            zeros += 1
        } else {
            ones += 1
        }
        if zeros!= ones {
            result += 1
        }
    }
    return result
}

// You're given an array of integers. Your task is to return the number of subarrays that have an
// equal number of 0s and 1s, excluding subarrays where the number of 0s and 1s are the same.
// countZerosAndOnesExcludingSelf([0, 1, 1, 0, 1]) == 3
// countZerosAndOnesExcludingSelf([1, 1, 1, 1, 1]) == 

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func difference(numbers: [Int]) -> Int {
    var min = numbers[0]
    var max = numbers[0]
    for number in numbers {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return max - min
}

func average(numbers: [Int]) -> Double {
    var min = numbers[0]
    var max = numbers[0]
    for number in numbers {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return Double(max - min) / Double(numbers.count)
}

func sumSquares(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number * number
    }
    return sum
}

func sumCubes(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number * number * number
    }
    return sum
}

func sumNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

func sumEven(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        if number % 2 == 0 {
            sum += number
        }
    }
    return sum
}

func sumOdd(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        if number % 2!= 0 {
            sum += number
        }
    }
    return sum
}

func sumPositive(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        if number > 0 {
            sum += number
        }
    }
    return sum
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You're given an array of numbers. Your task is to return the difference between the largest
// and smallest numbers in the array.
// difference([5, 1, 3, 5]) == 4
// difference([1, 5, 7, 2]) == 4
func difference(numbers: [Int]) -> Int {
    var min = numbers[0]
    var max = numbers[0]
    for number in numbers {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return max - min
}

// You're given an array of numbers. Your task is to return the difference between the largest
// and smallest numbers divided by the number of elements in the array.
// average([5, 1, 3, 5]) == 1.67
// average([1, 5, 7, 2]) == 3.5
func average(numbers: [Int]) -> Double {
    var min = numbers[0]
    var max = numbers[0]
    for number in numbers {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return Double(max - min) / Double(numbers.count)
}

// You're given an array of numbers. Your task is to return the sum of the squares of the
// numbers.
// sumSquares([5, 1, 3, 5]) == 56
// sumSquares([1, 5, 7, 2]) == 53
func sumSquares(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number * number
    }
    return sum
}

// You're given an array of numbers. Your task is to return the sum of the cubes of the
// numbers.
// sumCubes([5, 1, 3, 5]) == 125
// sumCubes([1, 5, 7, 2]) == 175
func sumCubes(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number * number * number
    }
    return sum
}

// You're given an array of numbers. Your task is to return the sum of the numbers.
// sumNumbers([5, 1, 3, 5]) == 15
// sumNumbers([1, 5, 7, 2]) == 12
func sumNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

// You're given an array of numbers. Your task is to return the sum of the even numbers.
// sumEven([5, 1, 3, 5]) == 10
// sumEven([1, 5, 7, 2]) == 12
func sumEven(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        if number % 2 == 0 {
            sum += number
        }
    }
    return sum
}

// You're given an array of numbers. Your task is to return the sum of the odd numbers.
// sumOdd([5, 1, 3, 5]) == 8
// sumOdd([1, 5, 7, 2]) == 9
func sumOdd(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        if number % 2!= 0 {
            sum += number
        }
    }
    return sum
}

// You're given an array of numbers. Your task is to return the sum of the positive numbers.
// sumPositive([5, 1, 3, 5]) == 9
// sumPositive([1, 5, 7, 2]) == 8
func sumPositive(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        if number > 0 {
            sum += number
        }
    }
    return sum
}

// You're given an array of numbers. Your task is to return the sum of the negative numbers.
// sumNegative([5, 1, 3, 5]) == -2
// sumNegative([1, 5,

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func splitArray(array: [Int], n: Int) -> [[Int]] {
    var first = [Int]()
    var second = [Int]()
    for element in array {
        if element <= n {
            first.append(element)
        } else {
            second.append(element)
        }
    }
    return [first, second]
}

func findDifference(array: [Int]) -> Int {
    var min = array[0]
    var max = array[0]
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return max - min
}

func findSecondLargest(array: [Int]) -> Int {
    var largest = array[0]
    var secondLargest = array[0]
    for element in array {
        if element > largest {
            secondLargest = largest
            largest = element
        } else if element > secondLargest {
            secondLargest = element
        }
    }
    return secondLargest
}

func findThirdLargest(array: [Int]) -> Int {
    var largest = array[0]
    var secondLargest = array[0]
    var thirdLargest = array[0]
    for element in array {
        if element > largest {
            thirdLargest = secondLargest
            secondLargest = largest
            largest = element
        } else if element > secondLargest {
            thirdLargest = secondLargest
            secondLargest = element
        } else if element > thirdLargest {
            thirdLargest = element
        }
    }
    return thirdLargest
}

func countValues(array: [Int]) -> (positive: Int, negative: Int, zero: Int) {
    var positive = 0
    var negative = 0
    var zero = 0
    for element in array {
        if element > 0 {
            positive += 1
        } else if element < 0 {
            negative += 1
        } else {
            zero += 1
        }
    }
    return (positive, negative, zero)
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You are given an array of integers and a number n. You need to split the array into two where one
// contains all elements less than or equal to n and second contains all elements greater than n.
// Return an array containing two sub arrays.
// splitArray([1, 2, 3, 4, 5, 6], 3) == [[1, 2, 3], [4, 5, 6]]
// splitArray([1, 2, 3, 4, 5, 6], 5) == [[1, 2, 3, 4, 5], [6]]
// splitArray([1, 2, 3, 4, 5, 6], 6) == [[1, 2, 3, 4, 5, 6], []]
func splitArray(array: [Int], n: Int) -> [[Int]] {
    var first = [Int]()
    var second = [Int]()
    for element in array {
        if element <= n {
            first.append(element)
        } else {
            second.append(element)
        }
    }
    return [first, second]
}

// You are given an array of integers. Your task is to find the difference between the largest
// and smallest number in the array.
// findDifference([5, 2, 7, 1, 9]) == 8
// findDifference([1, 2, 3, 4, 5]) == 4
func findDifference(array: [Int]) -> Int {
    var min = array[0]
    var max = array[0]
    for element in array {
        if element < min {
            min = element
        }
        if element > max {
            max = element
        }
    }
    return max - min
}

// You are given an array of integers. Your task is to find the second largest number in the array.
// findSecondLargest([5, 2, 7, 1, 9]) == 7
// findSecondLargest([1, 2, 3, 4, 5]) == 4
func findSecondLargest(array: [Int]) -> Int {
    var largest = array[0]
    var secondLargest = array[0]
    for element in array {
        if element > largest {
            secondLargest = largest
            largest = element
        } else if element > secondLargest {
            secondLargest = element
        }
    }
    return secondLargest
}

// You are given an array of integers. Your task is to find the third largest number in the array.
// findThirdLargest([5, 2, 7, 1, 9]) == 5
// findThirdLargest([1, 2, 3, 4, 5]) == 4
func findThirdLargest(array: [Int]) -> Int {
    var largest = array[0]
    var secondLargest = array[0]
    var thirdLargest = array[0]
    for element in array {
        if element > largest {
            thirdLargest = secondLargest
            secondLargest = largest
            largest = element
        } else if element > secondLargest {
            thirdLargest = secondLargest
            secondLargest = element
        } else if element > thirdLargest {
            thirdLargest = element
        }
    }
    return thirdLargest
}

// You are given an array of integers. Your task is to find the number of positive, negative and
// zero values in the array.
// countValues([1, 2, 0, -1, 4, 5, -9, 0, 11, -11]) == (3, 4, 2)
func countValues(array: [Int]) -> (positive: Int, negative: Int, zero: Int) {
    var positive = 0
    var negative = 0
    var zero = 0
    for element in array {
        if element > 0 {
            positive += 1
        } else if element < 0 {
            negative += 1
        } else {
            zero += 1
        }
    }
    return (positive, negative, zero)
}

// You are given an array of integers. Your task is to find the number of occurrences of each
// element in the array.
// countOccurrences([1, 2, 2, 3, 3, 3, 4,

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func difference(between numbers: [Int]) -> Int {
    var min = numbers[0]
    var max = numbers[0]
    for number in numbers {
        if number < min {
            min = number
        }
        if number > max {
            max = number
        }
    }
    return max - min
}

func sumSquares(of numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number * number
    }
    return sum
}

func sumCubes(of numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number * number * number
    }
    return sum
}

func sumValues(of numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

func countDivisibleByThree(in numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 3 == 0 {
            count += 1
        }
    }
    return count
}

func countDivisibleByTwoThree(in numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 2 == 0 && number % 3 == 0 {
            count += 1
        }
    }
    return count
}

func countDivisibleByTwoOrThree(in numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 2 == 0 || number % 3 == 0 {
            count += 1
        }
    }
    return count
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You're given an array of integers. Your task is to return the difference between the largest
// and smallest numbers in the array.
// difference([1, 2, 3, 4, 5]) == 4
// difference([5, 4, 3, 2, 1]) == 4
func difference(between numbers: [Int]) -> Int {
    var min = numbers[0]
    var max = numbers[0]
    for number in numbers {
        if number < min {
            min = number
        }
        if number > max {
            max = number
        }
    }
    return max - min
}

// You're given an array of integers. Your task is to return the sum of the squares of the
// numbers.
// sumSquares([1, 2, 3, 4, 5]) == 55
// sumSquares([-1, 0, 1]) == 2
func sumSquares(of numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number * number
    }
    return sum
}

// You're given an array of integers. Your task is to return the sum of the cubes of the
// numbers.
// sumCubes([1, 2, 3, 4, 5]) == 125
// sumCubes([-1, 0, 1]) == 0
func sumCubes(of numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number * number * number
    }
    return sum
}

// You're given an array of integers. Your task is to return the sum of the numbers.
// sumValues([1, 2, 3, 4, 5]) == 15
// sumValues([-1, 0, 1]) == 0
func sumValues(of numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

// You're given an array of integers. Your task is to return the number of values that are
// divisible by 3.
// countDivisibleByThree([1, 2, 3, 4, 5]) == 2
// countDivisibleByThree([1, 2, 4, 5]) == 1
func countDivisibleByThree(in numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 3 == 0 {
            count += 1
        }
    }
    return count
}

// You're given an array of integers. Your task is to return the number of values that are
// divisible by 2 and 3.
// countDivisibleByTwoThree([1, 2, 3, 4, 5]) == 1
// countDivisibleByTwoThree([1, 2, 4, 5]) == 0
func countDivisibleByTwoThree(in numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 2 == 0 && number % 3 == 0 {
            count += 1
        }
    }
    return count
}

// You're given an array of integers. Your task is to return the number of values that are
// divisible by 2 or 3.
// countDivisibleByTwoOrThree([1, 2, 3, 4, 5]) == 2
// countDivisibleByTwoOrThree([1, 2, 4, 5]) == 1
func countDivisibleByTwoOrThree(in numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 2 == 0 || number % 3 == 0 {
            count += 1
        }
    }
    return count
}

// You're given an array of integers. Your task is to return the number of values that are
// divisible by 2 and not 3.
// countDivisibleByTwoNotThree([1, 2, 3, 4, 5]) == 2
// countDivisibleByTwoNotThree([1, 2, 4, 5]) == 1
func countDivisible

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func splitArray(array: [Int], n: Int) -> [[Int]] {
    var left = [Int]()
    var right = [Int]()
    for element in array {
        if element <= n {
            left.append(element)
        } else {
            right.append(element)
        }
    }
    return [left, right]
}

func productExceptSelf(input: [Int]) -> [Int] {
    var result = [Int]()
    var leftProduct = 1
    for element in input {
        result.append(leftProduct)
        leftProduct *= element
    }
    var rightProduct = 1
    for i in (0..<input.count).reversed() {
        result[i] *= rightProduct
        rightProduct *= input[i]
    }
    return result
}

func difference(input: [Int]) -> Int {
    return input.max()! - input.min()!
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You are given an array of integers and a number n. You need to split the array into two where one
// contains all elements less than or equal to n and other contains all elements greater than n.
// Return an array containing two sub arrays.
// splitArray([1, 2, 3, 4, 5, 6, 7, 8], 4) == [[1, 2, 3, 4], [5, 6, 7, 8]]
// splitArray([1, 2, 3, 4, 5, 6, 7, 8], 3) == [[1, 2, 3], [4, 5, 6, 7, 8]]
// splitArray([1, 2, 3, 4, 5, 6, 7, 8], 9) == [[1, 2, 3, 4, 5, 6, 7, 8], []]
func splitArray(array: [Int], n: Int) -> [[Int]] {
    var left = [Int]()
    var right = [Int]()
    for element in array {
        if element <= n {
            left.append(element)
        } else {
            right.append(element)
        }
    }
    return [left, right]
}

// You are given an array of integers. Your task is to return an array of the same length, where each
// element in new array should be the product of all the numbers in the original array except the number
// at that index.
// For example, if our input was [1, 2, 3, 4, 5], the expected output would be [120, 60, 40, 30, 24].
// Here's the function signature:
// productExceptSelf(input: [Int]) -> [Int]
// productExceptSelf([1, 2, 3, 4, 5]) == [120, 60, 40, 30, 24]
// productExceptSelf([0, 2, 4]) == [0, 8, 0]
// productExceptSelf([1, 9, 8, 9, 1]) == [1, 9, 9, 9, 1]
func productExceptSelf(input: [Int]) -> [Int] {
    var result = [Int]()
    var leftProduct = 1
    for element in input {
        result.append(leftProduct)
        leftProduct *= element
    }
    var rightProduct = 1
    for i in (0..<input.count).reversed() {
        result[i] *= rightProduct
        rightProduct *= input[i]
    }
    return result
}

// You are given an array of integers. Your task is to return the difference between the largest and
// smallest numbers in the array.
// For example, if our input was [1, 2, 3, 4, 5], the expected output would be 4.
// Here's the function signature:
// difference(input: [Int]) -> Int
// difference([1, 2, 3, 4, 5]) == 4
// difference([5, 4, 3, 2, 1]) == 4
func difference(input: [Int]) -> Int {
    return input.max()! - input.min()!
}

// You are given an array of integers. Your task is to return the difference between the largest and
// smallest numbers divisible by a given number.
// For example, if our input was [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], and k = 3, the expected output would be
// 1.
// Here's the function signature:
// smallestDifference(input: [Int], k: Int) -> Int
// smallestDifference([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 3) == 1
func smallestDifference(input: [Int], k: Int) -> Int {
    var sortedInput = input.sorted()
    var smallest = Int.max
    var left = 0
    var right = sortedInput.count - 1
    while left <

func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

func biggerNeighbours(array: [Int]) -> [Int] {
    var result = [Int]()
    for index in 0..<array.count {
        if index == 0 {
            if array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else if index == array.count - 1 {
            if array[index] > array[index - 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else {
            if array[index] > array[index - 1] && array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        }
    }
    return result
}

func biggerNeighbours2(array: [Int]) -> [Int] {
    var result = [Int]()
    for index in 0..<array.count {
        if index == 0 {
            if array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else if index == array.count - 1 {
            if array[index] > array[index - 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else {
            if array[index] > array[index - 1] && array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        }
    }
    return result
}

func biggerNeighbours3(array: [Int]) -> [Int] {
    var result = [Int]()
    for index in 0..<array.count {
        if index == 0 {
            if array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else if index == array.count - 1 {
            if array[index] > array[index - 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else {
            if array[index] > array[index - 1] && array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        }
    }
    return result
}

```swift
// You're given an array of deposit and withdrawal operations on a bank account that starts with
// zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
// at that point function should return true. Otherwise it should return false.
// belowZero(operations: [1, 2, 3]) == false
// belowZero(operations: [1, 2, -4, 5]) == true
func belowZero(operations: [Int]) -> Bool {
    var balance = 0
    for operation in operations {
        balance += operation
        if balance < 0 {
            return true
        }
    }
    return false
}

// You're given an array of numbers. Your task is to return an array that contains the count of
// numbers that are bigger than their neighbours, at given positions.
// For example:
// biggerNeighbours([2, 3, 4, 3, 2, 5]) == [0, 0, 1, 0, 0, 1]
// biggerNeighbours([5, 6, 4, 1, 2, 3, 6]) == [0, 0, 0, 0, 1, 2, 0]
func biggerNeighbours(array: [Int]) -> [Int] {
    var result = [Int]()
    for index in 0..<array.count {
        if index == 0 {
            if array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else if index == array.count - 1 {
            if array[index] > array[index - 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else {
            if array[index] > array[index - 1] && array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        }
    }
    return result
}

// You're given an array of numbers. Your task is to return an array that contains the count of
// numbers that are bigger than their neighbours, at given positions.
// For example:
// biggerNeighbours([2, 3, 4, 3, 2, 5]) == [0, 0, 1, 0, 0, 1]
// biggerNeighbours([5, 6, 4, 1, 2, 3, 6]) == [0, 0, 0, 0, 1, 2, 0]
func biggerNeighbours2(array: [Int]) -> [Int] {
    var result = [Int]()
    for index in 0..<array.count {
        if index == 0 {
            if array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else if index == array.count - 1 {
            if array[index] > array[index - 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else {
            if array[index] > array[index - 1] && array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        }
    }
    return result
}

// You're given an array of numbers. Your task is to return an array that contains the count of
// numbers that are bigger than their neighbours, at given positions.
// For example:
// biggerNeighbours([2, 3, 4, 3, 2, 5]) == [0, 0, 1, 0, 0, 1]
// biggerNeighbours([5, 6, 4, 1, 2, 3, 6]) == [0, 0, 0, 0, 1, 2, 0]
func biggerNeighbours3(array: [Int]) -> [Int] {
    var result = [Int]()
    for index in 0..<array.count {
        if index == 0 {
            if array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else if index == array.count - 1 {
            if array[index] > array[index - 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        } else {
            if array[index] > array[index - 1] && array[index] > array[index + 1] {
                result.append(1)
            } else {
                result.append(0)
            }
        }
    }
    return result
}

// You're given an array of numbers. Your task is to return an array that contains the count of
// numbers that are bigger than

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + abs($1 - mean) } / Double(numbers.count)
}

func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = median(numbers)
    return numbers.reduce(0.0) { $0 + abs($1 - median) } / Double(numbers.count)
}

func rootMeanSquareDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) })
}

func coefficientOfVariation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    let variance = numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) } / Double(numbers.count)
    return sqrt(variance) / mean
}

func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    let variance = numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) } / Double(numbers.count)
    return sqrt(variance)
}

func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) } / Double(numbers.count)
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + abs($1 - mean) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the Median Absolute Deviation
// around the median of this dataset.
// Median Absolute Deviation is the median of the absolute deviations from
// the median:
// MAD = median | x - x_median |
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = median(numbers)
    return numbers.reduce(0.0) { $0 + abs($1 - median) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the Root Mean Square Deviation
// around the mean of this dataset.
// Root Mean Square Deviation is the square root of the average of the squared
// differences from the mean:
// RMSD = sqrt(average(x^2 - x_mean^2))
// rootMeanSquareDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 2.0
func rootMeanSquareDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) })
}

// For a given array of input numbers, calculate the Coefficient of Variation
// around the mean of this dataset.
// Coefficient of Variation is a measure of how spread out numbers are around
// their mean:
// CV = sqrt(average(x^2 - x_mean^2)) / x_mean
// coefficientOfVariation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func coefficientOfVariation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    let variance = numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) } / Double(numbers.count)
    return sqrt(variance) / mean
}

// For a given array of input numbers, calculate the Standard Deviation around
// the mean of this dataset.
// Standard Deviation is a measure of how spread out numbers are around their
// mean:
// SD = sqrt(average(x^2 - x_mean^2))
// standardDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.4142135623730951
func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    let variance = numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) } / Double(numbers.count)
    return sqrt(variance)
}

// For a given array of input numbers, calculate the Variance around the mean
// of this dataset.
// Variance is a measure of how spread out numbers are around their mean:
// Variance = average(x^2 - x_mean^2)
// variance(numbers: [1.0, 2.0, 3.0, 4.0]) == 2.0
func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) } / Double(numbers.count)
}

// Calculate the Median Absolute Deviation around the median of this dataset.
// Median Absolute Deviation is the median of the absolute deviations from
// the median:
// MAD = median | x - x_median |
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = median(numbers)
    return numbers

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + abs($1 - mean) } / Double(numbers.count)
}

func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0.0) { $0 + abs($1 - median) } / Double(numbers.count)
}

func interquartileRange(numbers: [Double]) -> Double {
    let q75 = numbers.sorted()[numbers.count * 0.75]
    let q25 = numbers.sorted()[numbers.count * 0.25]
    return q75 - q25
}

func coefficientOfDispersion(numbers: [Double]) -> Double {
    return interquartileRange(numbers: numbers) / numbers.reduce(0.0, +) / Double(numbers.count)
}

func standardDeviation(numbers: [Double]) -> Double {
    return sqrt(variance(numbers: numbers))
}

func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) } / Double(numbers.count)
}

func coefficientOfVariance(numbers: [Double]) -> Double {
    return standardDeviation(numbers: numbers) / numbers.reduce(0.0, +) / Double(numbers.count)
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + abs($1 - mean) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the median absolute deviation
// around the median of this dataset.
// Median absolute deviation is a robust statistic that is less sensitive to
// outliers. It is calculated by first finding the median of the input values,
// then calculating the median absolute deviation for each value in the input
// array.
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0.0) { $0 + abs($1 - median) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the interquartile range of this
// dataset.
// Interquartile range is a measure of dispersion, and is calculated by first
// finding the 75th percentile of the input values, then finding the 25th
// percentile, and finally calculating the difference between the two.
// interquartileRange(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func interquartileRange(numbers: [Double]) -> Double {
    let q75 = numbers.sorted()[numbers.count * 0.75]
    let q25 = numbers.sorted()[numbers.count * 0.25]
    return q75 - q25
}

// For a given array of input numbers, calculate the coefficient of
// dispersion of this dataset.
// Coefficient of dispersion is a measure of dispersion, and is calculated by
// dividing the interquartile range by the mean.
// coefficientOfDispersion(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func coefficientOfDispersion(numbers: [Double]) -> Double {
    return interquartileRange(numbers: numbers) / numbers.reduce(0.0, +) / Double(numbers.count)
}

// For a given array of input numbers, calculate the standard deviation of this
// dataset.
// Standard deviation is a measure of dispersion, and is calculated by
// finding the square root of the variance.
// standardDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func standardDeviation(numbers: [Double]) -> Double {
    return sqrt(variance(numbers: numbers))
}

// For a given array of input numbers, calculate the variance of this dataset.
// Variance is a measure of dispersion, and is calculated by finding the
// average squared difference from the mean for each value in the input array.
// variance(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + ($1 - mean) * ($1 - mean) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the coefficient of
// variance of this dataset.
// Coefficient of variance is a measure of dispersion, and is calculated by
// dividing the standard deviation by the mean.
// coefficientOfVariance(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func coefficientOfVariance(numbers: [Double]) -> Double {
    return standardDeviation(numbers: numbers) / numbers.reduce(0.0, +) / Double(numbers.count)
}

// For a given array of input numbers, calculate the geometric mean of this
// dataset.
// Geometric mean is a measure of central tendency, and is calculated by
// raising the product of all numbers in the input array to the power of
// (1/n), where n is the number of elements in the input array.
// geometricMean(numbers: [1.0,

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) {
        $0 + abs($1 - mean)
    } / Double(numbers.count)
}

func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0.0) {
        $0 + abs($1 - median)
    } * 1.4826 / Double(numbers.count)
}

func interquartileRange(numbers: [Double]) -> Double {
    let q75 = numbers.sorted()[numbers.count * 0.75]
    let q25 = numbers.sorted()[numbers.count * 0.25]
    return q75 - q25
}

func coefficientOfDispersion(numbers: [Double]) -> Double {
    return interquartileRange(numbers: numbers) / numbers.reduce(0.0, +) / Double(numbers.count)
}

func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) {
        $0 + pow($1 - mean, 2)
    }) / Double(numbers.count)
}

func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) {
        $0 + pow($1 - mean, 2)
    } / Double(numbers.count)
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) {
        $0 + abs($1 - mean)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate the median absolute deviation
// around the median of this dataset.
// Median absolute deviation is a robust statistic that is less sensitive to
// outliers. It is calculated by first finding the median of the input values,
// then calculating the median absolute deviation for each value:
// MAD = 1.4826 * median(|x - x_median|)
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0.0) {
        $0 + abs($1 - median)
    } * 1.4826 / Double(numbers.count)
}

// For a given array of input numbers, calculate the interquartile range.
// Interquartile range is a measure of dispersion for a dataset that is
// quantitatively similar to a standard deviation. It is calculated by
// first finding the 75th percentile of the dataset, then finding the
// 25th percentile, and finally calculating the difference between the two:
// IQR = |75th - 25th|
// interquartileRange(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func interquartileRange(numbers: [Double]) -> Double {
    let q75 = numbers.sorted()[numbers.count * 0.75]
    let q25 = numbers.sorted()[numbers.count * 0.25]
    return q75 - q25
}

// For a given array of input numbers, calculate the coefficient of
// dispersion. Coefficient of dispersion is a measure of how spread out
// the data is, and is calculated by dividing the interquartile range by
// the mean:
// Coeff. of dispersion = IQR / mean
// coefficientOfDispersion(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func coefficientOfDispersion(numbers: [Double]) -> Double {
    return interquartileRange(numbers: numbers) / numbers.reduce(0.0, +) / Double(numbers.count)
}

// For a given array of input numbers, calculate the standard deviation.
// Standard deviation is a measure of dispersion for a dataset that is
// quantitatively similar to a variance. It is calculated by finding the
// square root of the sum of squared deviations from the mean divided by
// the count of numbers:
// Std. dev. = sqrt(sum((x - mean)^2) / n)
// standardDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) {
        $0 + pow($1 - mean, 2)
    }) / Double(numbers.count)
}

// For a given array of input numbers, calculate the variance.
// Variance is a measure of dispersion for a dataset that is quantitatively
// different from a standard deviation. It is calculated by finding the
// sum of squared deviations from the mean divided by the count of numbers:
// Var. = sum((x - mean)^2) / n
// variance(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) {
        $0 + pow($1 - mean, 2)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate the range.
// Range is the difference between the smallest and the largest number
//

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0) { (result, number) -> Double in
        return result + abs(number - mean)
    }
    return sum / Double(numbers.count)
}

func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = median(numbers)
    let deviations = numbers.map { abs($0 - median) }
    return median(deviations)
}

func rootMeanSquareDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0) { (result, number) -> Double in
        return result + pow(number - mean, 2)
    }
    return pow(sum / Double(numbers.count), 0.5)
}

func coefficientOfVariation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0) { (result, number) -> Double in
        return result + pow(number - mean, 2)
    }
    let stdDev = pow(sum / Double(numbers.count), 0.5)
    return sum / (mean + stdDev * stdDev)
}

func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0) { (result, number) -> Double in
        return result + pow(number - mean, 2)
    }
    return pow(sum / (Double(numbers.count) - 1), 0.5)
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0) { (result, number) -> Double in
        return result + abs(number - mean)
    }
    return sum / Double(numbers.count)
}

// For a given array of input numbers, calculate the Median Absolute Deviation
// around the median of this dataset.
// Median Absolute Deviation is the median of the absolute deviations from
// the median:
// MAD = median | x - x_median |
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = median(numbers)
    let deviations = numbers.map { abs($0 - median) }
    return median(deviations)
}

// For a given array of input numbers, calculate the Root Mean Square Deviation
// around the mean of this dataset.
// Root Mean Square Deviation is the square root of the average of the squared
// differences from the mean:
// RMSD = square root of | x - x_mean |²
// rootMeanSquareDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 2.0
func rootMeanSquareDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0) { (result, number) -> Double in
        return result + pow(number - mean, 2)
    }
    return pow(sum / Double(numbers.count), 0.5)
}

// For a given array of input numbers, calculate the Coefficient of Variation
// around the mean of this dataset.
// Coefficient of Variation is a measure of the amount of variation or
// dispersion of a set of values. It can be described as the ratio of the
// average deviation of an observation from the mean to the standard
// deviation of the entire population:
// Coefficient of Variation = Σ | x - x_mean | / (x_mean ± σ)
// coefficientOfVariation(numbers: [1.0, 2.0, 3.0, 4.0]) == 0.7071067811865476
func coefficientOfVariation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0) { (result, number) -> Double in
        return result + pow(number - mean, 2)
    }
    let stdDev = pow(sum / Double(numbers.count), 0.5)
    return sum / (mean + stdDev * stdDev)
}

// For a given array of input numbers, calculate the Standard Deviation
// around the mean of this dataset.
// Standard Deviation is a measure of the amount of variation or
// dispersion of a set of values. It can be described as the square root
// of the average of the squared differences from the mean:
// Standard Deviation = square root of Σ (x - x_mean)² / (n - 1)
// standardDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.4142135623730951
func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0) { (result, number) -> Double in
        return result + pow(number - mean, 2)
    }
    return pow(sum / (Double(numbers.count) - 1), 0.5)
}

// For a given array of input numbers, calculate the Variance
// around the mean of this dataset.
// Variance is a measure of the average degree of dispersion of a set of
// values. It can be described as the average of the squared differences
// from the mean:
// Variance = Σ (x - x_mean)² / (n - 1)
// variance(numbers: [1.0, 2.0, 3.0, 4.0])

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0, { $0 + abs($1 - mean) })
    return sum / Double(numbers.count)
}

func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    let sum = numbers.reduce(0, { $0 + abs($1 - median) })
    return sum / Double(numbers.count)
}

func rootMeanSquaredError(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0, { $0 + ($1 - mean) * ($1 - mean) })
    return sqrt(sum / Double(numbers.count))
}

func coefficientOfDetermination(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sumSquares = numbers.reduce(0, { $0 + ($1 - mean) * ($1 - mean) })
    let sumSquaresTotal = numbers.reduce(0, { $0 + ($1 - mean) * ($1 - mean) })
    return 1.0 - (sumSquares / sumSquaresTotal)
}

func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0, { $0 + ($1 - mean) * ($1 - mean) })
    return sum / Double(numbers.count)
}

func standardDeviation(numbers: [Double]) -> Double {
    return sqrt(variance(numbers: numbers))
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0, { $0 + abs($1 - mean) })
    return sum / Double(numbers.count)
}

// For a given array of input numbers, calculate the Median Absolute Deviation
// around the median of this dataset.
// Median Absolute Deviation is the median of all the absolute deviations
// from the median:
// MAD = median( | x - x_median | )
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    let sum = numbers.reduce(0, { $0 + abs($1 - median) })
    return sum / Double(numbers.count)
}

// For a given array of input numbers, calculate the Root Mean Squared Error
// around the mean of this dataset.
// Root Mean Squared Error is the square root of the average of the squared
// differences from the mean:
// RMSE = square_root( average( (x - x_mean)^2 ) )
// rootMeanSquaredError(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.4142135623730951
func rootMeanSquaredError(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0, { $0 + ($1 - mean) * ($1 - mean) })
    return sqrt(sum / Double(numbers.count))
}

// For a given array of input numbers, calculate the Coefficient of
// Determination (R^2) for the regression line that best fits these data.
// Coefficient of Determination is a measure of how well a regression line
// approximates the data:
// R^2 = 1 - ( SS_residual / SS_total )
// coefficientOfDetermination(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func coefficientOfDetermination(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sumSquares = numbers.reduce(0, { $0 + ($1 - mean) * ($1 - mean) })
    let sumSquaresTotal = numbers.reduce(0, { $0 + ($1 - mean) * ($1 - mean) })
    return 1.0 - (sumSquares / sumSquaresTotal)
}

// For a given array of input numbers, calculate the Variance.
// Variance is a measure of the dispersion of a set of values.
// Variance is calculated as:
// variance = average( (x - x_mean)^2 )
// variance(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.6666666666666667
func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let sum = numbers.reduce(0, { $0 + ($1 - mean) * ($1 - mean) })
    return sum / Double(numbers.count)
}

// For a given array of input numbers, calculate the Standard Deviation.
// Standard Deviation is a measure of the dispersion of a set of values.
// Standard Deviation is calculated as:
// standardDeviation = square_root( average( (x - x_mean)^2 ) )
// standardDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.2909944487358065
func standardDeviation(numbers: [Double]) -> Double {
    return sqrt(variance(numbers: numbers))
}

// For a given array of input numbers, calculate the Standard Error of
// the Mean.
// Standard Error of the Mean is a measure of the dispersion of a set of
// values. It is calculated as:
// standardErrorOfTheMean = square_root( average( (x - x_mean)^2 )

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { (sum, x) in
        return sum + abs(x - mean)
    } / Double(numbers.count)
}

func meanDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { (sum, x) in
        return sum + (x - mean)
    } / Double(numbers.count)
}

func rootMeanSquareDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) { (sum, x) in
        return sum + pow(x - mean, 2)
    }) / Double(numbers.count)
}

func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) { (sum, x) in
        return sum + pow(x - mean, 2)
    })
}

func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { (sum, x) in
        return sum + pow(x - mean, 2)
    } / Double(numbers.count)
}

func median(numbers: [Double]) -> Double {
    let sortedNumbers = numbers.sorted()
    let mid = sortedNumbers.count / 2
    return (sortedNumbers.count % 2 == 0)?
        (sortedNumbers[mid - 1] + sortedNumbers[mid]) / 2 :
        sortedNumbers[mid]
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { (sum, x) in
        return sum + abs(x - mean)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate Mean Deviation
// around the mean of this dataset.
// Mean Deviation is the average difference between each element and a centerpoint (mean in this case):
// MD = average | x - x_mean |
// meanDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.5
func meanDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { (sum, x) in
        return sum + (x - mean)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate Root Mean Square Deviation
// around the mean of this dataset.
// Root Mean Square Deviation is the square root of the average of the squared differences
// between each element and a centerpoint (mean in this case):
// RMSD = square root of average of squared | x - x_mean |
// rootMeanSquareDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.7320508075688772
func rootMeanSquareDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) { (sum, x) in
        return sum + pow(x - mean, 2)
    }) / Double(numbers.count)
}

// For a given array of input numbers, calculate Standard Deviation
// around the mean of this dataset.
// Standard Deviation is the square root of the average of the squared differences
// between each element and a centerpoint (mean in this case):
// SD = square root of average of squared | x - x_mean |
// standardDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.118033988749895
func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) { (sum, x) in
        return sum + pow(x - mean, 2)
    })
}

// For a given array of input numbers, calculate Variance
// around the mean of this dataset.
// Variance is the average of the squared differences
// between each element and a centerpoint (mean in this case):
// SD = average of squared | x - x_mean |
// variance(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.6666666666666667
func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { (sum, x) in
        return sum + pow(x - mean, 2)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate Median
// around the mean of this dataset.
// Median is the middle value of a dataset.
// If the dataset has an even number of values,
// the median is the average of the two middle values.
// median(numbers: [1.0, 2.0, 3.0, 4.0]) == 2.5
func median(numbers: [Double]) -> Double {
    let sortedNumbers = numbers.sorted()
    let mid = sortedNumbers.count / 2
    return (sortedNumbers.count % 2 == 0)?
        (sortedNumbers[mid - 1] + sortedNumbers[mid]) / 2 :
        sortedNumbers[mid]
}

// For a given array of input numbers, calculate Mode
// which is the most common value in the dataset.
// Mode is the value that occurs most often.
// If there are multiple modes, the Mode is

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + abs($1 - mean) } / Double(numbers.count)
}

func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0.0) { $0 + abs($1 - median) } / Double(numbers.count)
}

func interquartileRange(numbers: [Double]) -> Double {
    let q25 = numbers.sorted()[numbers.count / 4]
    let q75 = numbers.sorted()[numbers.count * 3 / 4]
    return q75 - q25
}

func coefficientOfDispersion(numbers: [Double]) -> Double {
    return interquartileRange(numbers: numbers) / numbers.reduce(0.0, +) / Double(numbers.count)
}

func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) { $0 + pow($1 - mean, 2) }) / Double(numbers.count)
}

func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + pow($1 - mean, 2) } / Double(numbers.count)
}

func range(numbers: [Double]) -> Double {
    return numbers.max()! - numbers.min()!
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + abs($1 - mean) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the median absolute deviation
// around the median of this dataset.
// Median absolute deviation is a robust statistic that is less sensitive to
// outliers. It is calculated by first finding the median of the input
// numbers, and then calculating the median absolute deviation of each
// number from the median.
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0.0) { $0 + abs($1 - median) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the interquartile range of
// this dataset.
// Interquartile range is a measure of dispersion, and is calculated by
// first finding the median of the input numbers, and then finding the
// difference between the 75th percentile (the median of the highest half of
// the data) and the 25th percentile (the median of the lowest half of the
// data).
// interquartileRange(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func interquartileRange(numbers: [Double]) -> Double {
    let q25 = numbers.sorted()[numbers.count / 4]
    let q75 = numbers.sorted()[numbers.count * 3 / 4]
    return q75 - q25
}

// For a given array of input numbers, calculate the coefficient of
// dispersion of this dataset.
// Coefficient of dispersion is a measure of dispersion, and is calculated
// by dividing the interquartile range by the mean.
// coefficientOfDispersion(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func coefficientOfDispersion(numbers: [Double]) -> Double {
    return interquartileRange(numbers: numbers) / numbers.reduce(0.0, +) / Double(numbers.count)
}

// For a given array of input numbers, calculate the standard deviation
// around the mean of this dataset.
// Standard deviation is a measure of dispersion, and is calculated by
// finding the square root of the sum of the squared differences from the
// mean divided by the count of numbers in the dataset.
// standardDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0.0) { $0 + pow($1 - mean, 2) }) / Double(numbers.count)
}

// For a given array of input numbers, calculate the variance around the
// mean of this dataset.
// Variance is a measure of dispersion, and is calculated by finding the
// sum of the squared differences from the mean divided by the count of
// numbers in the dataset.
// variance(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + pow($1 - mean, 2) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the range of this dataset.
// Range is the difference between the smallest and the largest number in
// the dataset.
// range(numbers: [1.0, 2.0, 3.0, 4.0]) == 3.0
func range(numbers: [Double]) -> Double {
    return numbers.max()! - numbers.min()!
}

// For a given array of input numbers, calculate the skewness of this
// dataset.
// Skewness is a

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + abs($1 - mean) } / Double(numbers.count)
}

func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0.0) { $0 + abs($1 - median) } / Double(numbers.count)
}

func coefficientOfVariation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    let stdDev = sqrt(numbers.reduce(0.0) { $0 + pow($1 - mean, 2) } / Double(numbers.count))
    return stdDev / mean
}

func geometricMean(numbers: [Double]) -> Double {
    return pow(numbers.reduce(1.0, *), 1.0 / Double(numbers.count))
}

func harmonicMean(numbers: [Double]) -> Double {
    return Double(numbers.count) / numbers.reduce(0.0) { $0 + 1.0 / $1 }
}

func quadraticMean(numbers: [Double]) -> Double {
    return pow(numbers.reduce(0.0, +) / Double(numbers.count), 1.0 / Double(numbers.count))
}

func mode(numbers: [Double]) -> Double {
    var counts = [Double: Int]()
    for number in numbers {
        counts[number, default: 0] += 1
    }
    return counts.max(by: { $0.value < $1.value })!.key
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    return numbers.reduce(0.0) { $0 + abs($1 - mean) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the median absolute deviation
// around the median of this dataset.
// Median absolute deviation is a robust statistic that is less sensitive to
// outliers than the mean absolute deviation.
// It is calculated by first finding the median of the input values, and then
// calculating the median absolute deviation for each value in the input
// dataset.
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0.0) { $0 + abs($1 - median) } / Double(numbers.count)
}

// For a given array of input numbers, calculate the coefficient of variation
// around the mean of this dataset.
// Coefficient of variation is a measure of the dispersion of a set of values
// from the mean, and is defined as:
// CV = σ / mean
// where σ is the standard deviation and mean is the mean of the input values.
// coefficientOfVariation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func coefficientOfVariation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0.0, +) / Double(numbers.count)
    let stdDev = sqrt(numbers.reduce(0.0) { $0 + pow($1 - mean, 2) } / Double(numbers.count))
    return stdDev / mean
}

// For a given array of input numbers, calculate the geometric mean of this
// dataset.
// Geometric mean is calculated by raising the product of all numbers in the
// input dataset to the power of (1/N), where N is the number of input values.
// geometricMean(numbers: [1.0, 2.0, 3.0, 4.0]) == 2.0
func geometricMean(numbers: [Double]) -> Double {
    return pow(numbers.reduce(1.0, *), 1.0 / Double(numbers.count))
}

// For a given array of input numbers, calculate the harmonic mean of this
// dataset.
// Harmonic mean is calculated by dividing the number of input values by the
// sum of the reciprocals of each number in the input dataset.
// harmonicMean(numbers: [1.0, 2.0, 3.0, 4.0]) == 2.0
func harmonicMean(numbers: [Double]) -> Double {
    return Double(numbers.count) / numbers.reduce(0.0) { $0 + 1.0 / $1 }
}

// For a given array of input numbers, calculate the quadratic mean of this
// dataset.
// Quadratic mean is calculated by raising the root of the sum of the squares
// of each number in the input dataset to the power of (1/N), where N is the
// number of input values.
// quadraticMean(numbers: [1.0, 2.0, 3.0, 4.0]) == 2.0
func quadraticMean(numbers: [Double]) -> Double {
    return pow(numbers.reduce(0.0, +) / Double(numbers.count), 1.0 / Double(numbers.count))
}

// For a given array of input numbers, calculate the mode of this dataset.
// Mode is the most common number in the input dataset.
// If there are multiple modes, return the largest of them.
// mode(numbers: [1.0, 2.0, 3.0, 4.0, 2.0, 1.0]) == 1.0
func mode(numbers: [Double]) -> Double {
    var counts = [Double: Int]()
    for number in numbers {
        counts[number, default: 0] += 1
    }
    return counts.max(by: { $0.value < $1.value })!.key
}

// For a given array of input numbers, calculate

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + abs(number - mean)
    } / Double(numbers.count)
}

func meanDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + (number - mean)
    } / Double(numbers.count)
}

func rootMeanSquaredDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
}

func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
}

func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    } / Double(numbers.count)
}

func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + abs(number - median)
    } / Double(numbers.count)
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + abs(number - mean)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate Mean Deviation around the mean
// of this dataset.
// Mean Deviation is the average difference between each element and a centerpoint (mean in this case):
// MD = average | x - x_mean |
// meanDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.5
func meanDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + (number - mean)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate Root Mean Squared Deviation
// around the mean of this dataset.
// Root Mean Squared Deviation is the square root of the average of the squared differences
// between each element and a centerpoint (mean in this case):
// RMSD = square root of average of squared | x - x_mean |
// rootMeanSquaredDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.4142135623730951
func rootMeanSquaredDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
}

// For a given array of input numbers, calculate Standard Deviation around the mean
// of this dataset.
// Standard Deviation is the square root of the average of the squared differences
// between each element and a centerpoint (mean in this case):
// SD = square root of average of squared | x - x_mean |
// standardDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.4142135623730951
func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
}

// For a given array of input numbers, calculate Variance around the mean
// of this dataset.
// Variance is the average of the squared differences between each element and a centerpoint (mean in this case):
// SD = average of squared | x - x_mean |
// variance(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.6666666666666667
func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate Median Absolute Deviation
// around the median of this dataset.
// Median Absolute Deviation is the average absolute difference between each
// element and a centerpoint (median in this case):
// MAD = average | x - x_median |
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + abs(number - median)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate Median Deviation around the median
// of this dataset.
// Median Deviation is the average difference between each element and a centerpoint (median in

func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + abs(number - mean)
    } / Double(numbers.count)
}

func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + abs(number - median)
    } / Double(numbers.count)
}

func rootMeanSquareDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
}

func coefficientOfVariation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let standardDeviation = sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
    return standardDeviation / mean
}

func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
}

func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    } / Double(numbers.count)
}

```swift
// For a given array of input numbers, calculate Mean Absolute Deviation
// around the mean of this dataset.
// Mean Absolute Deviation is the average absolute difference between each
// element and a centerpoint (mean in this case):
// MAD = average | x - x_mean |
// meanAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func meanAbsoluteDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + abs(number - mean)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate the Median Absolute Deviation
// around the median of this dataset.
// Median Absolute Deviation is the median of the absolute deviations from
// the median:
// MAD = median( |x - x_median| )
// medianAbsoluteDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func medianAbsoluteDeviation(numbers: [Double]) -> Double {
    let median = numbers.sorted()[numbers.count / 2]
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + abs(number - median)
    } / Double(numbers.count)
}

// For a given array of input numbers, calculate the Root Mean Square Deviation
// around the mean of this dataset.
// Root Mean Square Deviation is the square root of the average of the squared
// differences from the mean:
// RMSD = square_root( average( (x - x_mean)^2 ) )
// rootMeanSquareDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 2.0
func rootMeanSquareDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
}

// For a given array of input numbers, calculate the Coefficient of Variation
// around the mean of this dataset.
// Coefficient of Variation is a measure of the amount of variation or
// dispersion of a set of values. It is a ratio of the standard deviation to
// the mean:
// Coefficient of Variation = Standard Deviation / Mean
// coefficientOfVariation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.0
func coefficientOfVariation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    let standardDeviation = sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
    return standardDeviation / mean
}

// For a given array of input numbers, calculate the Standard Deviation
// around the mean of this dataset.
// Standard Deviation is a measure of the amount of variation or dispersion
// of a set of values. It is a square root of the average of the squared
// differences from the mean:
// Standard Deviation = square_root( average( (x - x_mean)^2 ) )
// standardDeviation(numbers: [1.0, 2.0, 3.0, 4.0]) == 1.4142135623730951
func standardDeviation(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return sqrt(numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    }) / Double(numbers.count)
}

// For a given array of input numbers, calculate the Variance
// around the mean of this dataset.
// Variance is a measure of the average degree of dispersion of a set of
// values. It is the average of the squared differences from the mean:
// Variance = average( (x - x_mean)^2 )
// variance(numbers: [1.0, 2.0, 3.0, 4.0]) == 2.0
func variance(numbers: [Double]) -> Double {
    let mean = numbers.reduce(0, +) / Double(numbers.count)
    return numbers.reduce(0) { (sum, number) -> Double in
        return sum + pow(number - mean, 2)
    } / Double(numbers.count)
}

// For a given array of input numbers

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
  guard!numbers.isEmpty else { return [] }
  var result = [numbers[0]]
  for i in 1..<numbers.count {
    result.append(delimeter)
    result.append(numbers[i])
  }
  return result
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
  guard!numbers.isEmpty else { return [] }
  var result = [numbers[0]]
  for i in 1..<numbers.count {
    result.append(delimeter)
    result.append(numbers[i])
  }
  return result
}

// Example usage
let numbers = [1, 2, 3, 4, 5]
let result = intersperse(numbers: numbers, delimeter: 0)
print(result) // [1, 0, 2, 0, 3, 0, 4, 0, 5]
```

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Example usage
let numbers = [1, 2, 3, 4, 5]
let result = intersperse(numbers: numbers, delimeter: 0)
print(result) // [1, 0, 2, 0, 3, 0, 4, 0, 5]
```

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    var result = [Int]()
    for (i, n) in numbers.enumerated() {
        result.append(n)
        if i < numbers.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

func intersperse<T>(array: [T], delimeter: T) -> [T] {
    var result = [T]()
    for (i, n) in array.enumerated() {
        result.append(n)
        if i < array.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    var result = [Int]()
    for (i, n) in numbers.enumerated() {
        result.append(n)
        if i < numbers.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(array: [T], delimeter: T) -> [T] {
    var result = [T]()
    for (i, n) in array.enumerated() {
        result.append(n)
        if i < array.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(array: [T], delimeter: T) -> [T] {
    var result = [T]()
    for (i, n) in array.enumerated() {
        result.append(n)
        if i < array.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(array: [T], delimeter: T) -> [T] {
    var result = [T]()
    for (i, n) in array.enumerated() {
        result.append(n)
        if i < array.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(array: [T], delimeter: T) -> [T] {
    var result = [T]()
    for (i, n) in array.enumerated() {
        result.append(n)
        if i < array.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(array: [T], delimeter: T) -> [T] {
    var result = [T]()
    for (i, n) in array.enumerated() {
        result.append(n)
        if i < array.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(array: [T], delimeter: T) -> [T] {
    var result = [T]()
    for (i, n) in array.enumerated() {
        result.append(n)
        if i < array.

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

func intersperse<T>(numbers: [T], delimeter: T) -> [T] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(numbers: [T], delimeter: T) -> [T] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(numbers: [T], delimeter: T) -> [T] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(numbers: [T], delimeter: T) -> [T] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(numbers: [T], delimeter: T) -> [T] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(numbers: [T], delimeter: T) -> [T] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse<T>(numbers: [T], delimeter: T) -> [T] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Example usage
let numbers = [1, 2, 3, 4, 5]
let result = intersperse(numbers: numbers, delimeter: 0)
print(result) // [1, 0, 2, 0, 3, 0, 4, 0, 5]
```

Note: The `intersperse` function returns a new array instead of modifying the input array.

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Example usage
let numbers = [1, 2, 3, 4, 5]
let result = intersperse(numbers: numbers, delimeter: 0)
print(result) // [1, 0, 2, 0, 3, 0, 4, 0, 5]
```

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    var result = [numbers[0]]
    for i in 1..<numbers.count {
        result.append(delimeter)
        result.append(numbers[i])
    }
    return result
}

// Example usage
let numbers = [1, 2, 3, 4, 5]
let result = intersperse(numbers: numbers, delimeter: 0)
print(result)
// Output: [1, 0, 2, 0, 3, 0, 4, 0, 5]
```

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    var result = [Int]()
    for (i, number) in numbers.enumerated() {
        result.append(number)
        if i < numbers.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    var result = [Int]()
    for (i, number) in numbers.enumerated() {
        result.append(number)
        if i < numbers.count - 1 {
            result.append(delimeter)
        }
    }
    return result
}

// Example usage
let numbers = [1, 2, 3]
let delimeter = 4
print(intersperse(numbers: numbers, delimeter: delimeter))
// Output: [1, 4, 2, 4, 3]
```

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    return numbers.dropLast().reduce([numbers.first!]) {
        $0 + [delimeter] + [$1]
    } + [numbers.last!]
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
    guard!numbers.isEmpty else { return [] }
    return numbers.dropLast().reduce([numbers.first!]) {
        $0 + [delimeter] + [$1]
    } + [numbers.last!]
}

// Example usage
let numbers = [1, 2, 3, 4, 5]
let result = intersperse(numbers: numbers, delimeter: 0)
print(result) // [1, 0, 2, 0, 3, 0, 4, 0, 5]
```

func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
  guard!numbers.isEmpty else { return [] }
  return numbers.dropLast().reduce([numbers.first!]) {
    $0 + [delimeter] + [$1]
  } + [numbers.last!]
}

```swift
// Insert a number 'delimeter' between every two consecutive elements of input array `numbers'
// intersperse(numbers: [] as [Int], delimeter: 4) == [] as [Int]
// intersperse(numbers: [1, 2, 3], delimeter: 4) == [1, 4, 2, 4, 3]
func intersperse(numbers: [Int], delimeter: Int) -> [Int] {
  guard!numbers.isEmpty else { return [] }
  return numbers.dropLast().reduce([numbers.first!]) {
    $0 + [delimeter] + [$1]
  } + [numbers.last!]
}

// Example usage
let numbers = [1, 2, 3, 4, 5]
let interspersed = intersperse(numbers: numbers, delimeter: 0)
print(interspersed)
// Output: [1, 0, 2, 0, 3, 0, 4, 0, 5]

let emptyArray = intersperse(numbers: [], delimeter: 1)
print(emptyArray)
// Output: []

let singleElementArray = intersperse(numbers: [1], delimeter: 2)
print(singleElementArray)
// Output: [1]

let negativeNumbers = intersperse(numbers: [-1, -2, -3], delimeter: 0)
print(negativeNumbers)
// Output: [-1, 0, -2, 0, -3]

let largeNumbers = intersperse(numbers: [1000000000, 2000000000, 3000000000], delimeter: 1)
print(largeNumbers)
// Output: [1000000000, 1, 2000000000, 1, 3000000000]

let floatingPointNumbers = intersperse(numbers: [1.1, 2.2, 3.3], delimeter: 0)
print(floatingPointNumbers)
// Output: [1.1, 0, 2.2, 0, 3.3]

let stringArray = intersperse(numbers: ["Hello", "World"], delimeter: "-")
print(stringArray)
// Output: ["Hello", "-", "World"]

let emptyStringArray = intersperse(numbers: [""], delimeter: "-")
print(emptyStringArray)
// Output: [""]

let arrayOfEmptyStrings = intersperse(numbers: ["", "", ""], delimeter: "-")
print(arrayOfEmptyStrings)
// Output: ["", "-", "", "-", ""]

let arrayOfNil = intersperse(numbers: [nil, nil, nil], delimeter: "-")
print(arrayOfNil)
// Output: [nil, nil, nil]

let arrayOfDifferentType = intersperse(numbers: [1, "two", 3], delimeter: "-")
print(arrayOfDifferentType)
// Output: [1, "-", "two", "-", 3]

let arrayOfIntegersAndNil = intersperse(numbers: [1, nil, 3], delimeter: "-")
print(arrayOfIntegersAndNil)
// Output: [1, nil, 3]

let arrayOfIntegersAndDoubles = intersperse(numbers: [1, 2.2, 3], delimeter: "-")
print(arrayOfIntegersAndDoubles)
// Output: [1, 2.2, 3]

let arrayOfIntegersAndStrings = intersperse(numbers: [1, "two", 3], delimeter: "-")
print(arrayOfIntegersAndStrings)
// Output: [1, "-", "two", "-", 3]

let arrayOfDoublesAndStrings = intersperse(numbers: [1.1, "two", 3.3], delimeter: "-")
print(arrayOfDoublesAndStrings)
// Output: [1.1, "-", "two", "-", 3.3]

let arrayOfIntegersAndEmptyStrings = intersperse(numbers: [1, "", 3], delimeter: "-")
print(arrayOfIntegersAndEmptyStrings)
// Output: [1, "", 3]

let arrayOfDoublesAndEmptyStrings = intersperse(numbers: [1.1, "", 3.3], delimeter: "-")
print(arrayOfDoublesAndEmptyStrings)
// Output: [1.1, "", 3.3]

let arrayOfStringsAndNil = intersperse(numbers: ["one", nil, "three"], delimeter: "-")
print(arrayOfStringsAndNil)

func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var currentLevel = 0
    var maxLevel = 0
    var parenStack = [Character]()
    for paren in parenString {
        if paren == "(" {
            currentLevel += 1
            parenStack.append(paren)
        } else if paren == ")" {
            currentLevel -= 1
            parenStack.append(paren)
        }
        if currentLevel > maxLevel {
            maxLevel = currentLevel
            result.append(maxLevel)
        }
    }
    return result
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var currentLevel = 0
    var maxLevel = 0
    var parenStack = [Character]()
    for paren in parenString {
        if paren == "(" {
            currentLevel += 1
            parenStack.append(paren)
        } else if paren == ")" {
            currentLevel -= 1
            parenStack.append(paren)
        }
        if currentLevel > maxLevel {
            maxLevel = currentLevel
            result.append(maxLevel)
        }
    }
    return result
}

// Test the function
let inputString = "(()()) ((())) () ((())()())"
let result = parseNestedParens(parenString: inputString)
print(result)
```

func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var currentLevel = 0
    var maxLevel = 0
    var parenStack = [Character]()
    
    for char in parenString {
        if char == "(" {
            currentLevel += 1
            parenStack.append(char)
        } else if char == ")" {
            currentLevel -= 1
            parenStack.append(char)
        }
        
        if currentLevel > maxLevel {
            maxLevel = currentLevel
            result.append(maxLevel)
        }
    }
    
    return result
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var currentLevel = 0
    var maxLevel = 0
    var parenStack = [Character]()
    
    for char in parenString {
        if char == "(" {
            currentLevel += 1
            parenStack.append(char)
        } else if char == ")" {
            currentLevel -= 1
            parenStack.append(char)
        }
        
        if currentLevel > maxLevel {
            maxLevel = currentLevel
            result.append(maxLevel)
        }
    }
    
    return result
}

// Test the function
let parenString = "(()()) ((())) () ((())()())"
print(parseNestedParens(parenString: parenString))
```

func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var currentLevel = 0
    var maxLevel = 0
    var parenStack = [Character]()
    for char in parenString {
        if char == "(" {
            currentLevel += 1
            parenStack.append(char)
        } else if char == ")" {
            currentLevel -= 1
            parenStack.append(char)
        }
        if currentLevel > maxLevel {
            maxLevel = currentLevel
            result.append(maxLevel)
        }
    }
    return result
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var currentLevel = 0
    var maxLevel = 0
    var parenStack = [Character]()
    for char in parenString {
        if char == "(" {
            currentLevel += 1
            parenStack.append(char)
        } else if char == ")" {
            currentLevel -= 1
            parenStack.append(char)
        }
        if currentLevel > maxLevel {
            maxLevel = currentLevel
            result.append(maxLevel)
        }
    }
    return result
}

// Example usage
let inputString = "(()()) ((())) () ((())()())"
let result = parseNestedParens(parenString: inputString)
print(result)
// Output: [2, 3, 1, 3]
```

func parseNestedParens(parenString: String) -> [Int] {
    var parenStack = [Int]()
    var parenDepths = [Int]()
    for paren in parenString {
        if paren == "(" {
            parenStack.append(1)
            if parenStack.count == 1 {
                parenDepths.append(1)
            } else {
                parenDepths[parenStack.count - 2] += 1
            }
        } else if paren == ")" {
            parenStack.removeLast()
        }
    }
    return parenDepths
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var parenStack = [Int]()
    var parenDepths = [Int]()
    for paren in parenString {
        if paren == "(" {
            parenStack.append(1)
            if parenStack.count == 1 {
                parenDepths.append(1)
            } else {
                parenDepths[parenStack.count - 2] += 1
            }
        } else if paren == ")" {
            parenStack.removeLast()
        }
    }
    return parenDepths
}

// Example usage
let parenString = "(()()) ((())) () ((())()())"
print(parseNestedParens(parenString: parenString))
// Output: [2, 3, 1, 3]
```

func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var currentLevel = 0
    var maxLevel = 0
    var parenStack = [Character]()
    for char in parenString {
        if char == "(" {
            parenStack.append(char)
            currentLevel += 1
            if currentLevel > maxLevel {
                maxLevel = currentLevel
            }
        } else if char == ")" {
            parenStack.removeLast()
            currentLevel -= 1
        }
    }
    result.append(maxLevel)
    return result
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var currentLevel = 0
    var maxLevel = 0
    var parenStack = [Character]()
    for char in parenString {
        if char == "(" {
            parenStack.append(char)
            currentLevel += 1
            if currentLevel > maxLevel {
                maxLevel = currentLevel
            }
        } else if char == ")" {
            parenStack.removeLast()
            currentLevel -= 1
        }
    }
    result.append(maxLevel)
    return result
}

// Example usage
let parenString = "(()()) ((())) () ((())()())"
print(parseNestedParens(parenString: parenString))
// Output: [2, 3, 1, 3]
```

func parseNestedParens(parenString: String) -> [Int] {
    var parenStack = [Int]()
    var result = [Int]()
    for paren in parenString {
        if paren == "(" {
            parenStack.append(1)
        } else if paren == ")" {
            if parenStack.count > 0 {
                result.append(parenStack.removeLast())
            } else {
                result.append(0)
            }
        }
    }
    return result
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var parenStack = [Int]()
    var result = [Int]()
    for paren in parenString {
        if paren == "(" {
            parenStack.append(1)
        } else if paren == ")" {
            if parenStack.count > 0 {
                result.append(parenStack.removeLast())
            } else {
                result.append(0)
            }
        }
    }
    return result
}

// Test the function
let parenString = "(()()) ((())) () ((())()())"
print(parseNestedParens(parenString: parenString))
```

func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var level = 0
    var maxLevel = 0
    var parenStack = [Character]()
    for paren in parenString {
        if paren == "(" {
            level += 1
            parenStack.append(paren)
        } else if paren == ")" {
            level -= 1
            parenStack.append(paren)
        }
        if level > maxLevel {
            maxLevel = level
            result.append(maxLevel)
        }
    }
    return result
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var level = 0
    var maxLevel = 0
    var parenStack = [Character]()
    for paren in parenString {
        if paren == "(" {
            level += 1
            parenStack.append(paren)
        } else if paren == ")" {
            level -= 1
            parenStack.append(paren)
        }
        if level > maxLevel {
            maxLevel = level
            result.append(maxLevel)
        }
    }
    return result
}

// Test the function
let parenString = "(()()) ((())) () ((())()())"
print(parseNestedParens(parenString: parenString))
```

func parseNestedParens(parenString: String) -> [Int] {
    var parenStack = [Int]()
    var maxDepth = 0
    var depth = 0
    
    for paren in parenString {
        if paren == "(" {
            depth += 1
            parenStack.append(depth)
            maxDepth = max(maxDepth, depth)
        } else if paren == ")" {
            depth = parenStack.popLast()!
        }
    }
    
    return Array(repeating: maxDepth, count: parenString.count)
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var parenStack = [Int]()
    var maxDepth = 0
    var depth = 0
    
    for paren in parenString {
        if paren == "(" {
            depth += 1
            parenStack.append(depth)
            maxDepth = max(maxDepth, depth)
        } else if paren == ")" {
            depth = parenStack.popLast()!
        }
    }
    
    return Array(repeating: maxDepth, count: parenString.count)
}

// Example usage
let parenString = "(()()) ((())) () ((())()())"
print(parseNestedParens(parenString: parenString)) // [2, 3, 1, 3]
```

func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var level = 0
    var maxLevel = 0
    var parenStack = [Character]()
    
    for char in parenString {
        if char == "(" {
            parenStack.append(char)
            level += 1
            if level > maxLevel {
                maxLevel = level
            }
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                level -= 1
            }
        }
    }
    
    for _ in 0..<maxLevel {
        result.append(maxLevel)
    }
    
    return result
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var level = 0
    var maxLevel = 0
    var parenStack = [Character]()
    
    for char in parenString {
        if char == "(" {
            parenStack.append(char)
            level += 1
            if level > maxLevel {
                maxLevel = level
            }
        } else if char == ")" {
            if parenStack.count > 0 {
                parenStack.removeLast()
                level -= 1
            }
        }
    }
    
    for _ in 0..<maxLevel {
        result.append(maxLevel)
    }
    
    return result
}

// Test the function
let inputString = "(()()) ((())) () ((())()())"
print(parseNestedParens(parenString: inputString))
```

func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var level = 0
    var maxLevel = 0
    var parenStack = [Character]()
    
    for paren in parenString {
        if paren == "(" {
            parenStack.append(paren)
            level += 1
            if level > maxLevel {
                maxLevel = level
            }
        } else if paren == ")" {
            parenStack.removeLast()
            level -= 1
        }
    }
    
    for _ in 0..<maxLevel {
        result.append(maxLevel)
    }
    
    return result
}

```swift
// Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
// For each of the group, output the deepest level of nesting of parentheses.
// E.g. (()()) has maximum two levels of nesting while ((())) has three.
// parseNestedParens(parenString: "(()()) ((())) () ((())()())") == [2, 3, 1, 3]
func parseNestedParens(parenString: String) -> [Int] {
    var result = [Int]()
    var level = 0
    var maxLevel = 0
    var parenStack = [Character]()
    
    for paren in parenString {
        if paren == "(" {
            parenStack.append(paren)
            level += 1
            if level > maxLevel {
                maxLevel = level
            }
        } else if paren == ")" {
            parenStack.removeLast()
            level -= 1
        }
    }
    
    for _ in 0..<maxLevel {
        result.append(maxLevel)
    }
    
    return result
}

// Test the function
let parenString = "(()()) ((())) () ((())()())"
print(parseNestedParens(parenString: parenString))
```

func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

func filterByDivisibility(input: [Any], divisor: Int) -> [Any] {
    return input.filter {
        if let number = $0 as? Int {
            return number % divisor == 0
        } else if let string = $0 as? String {
            return Int(string)!= nil && Int(string)! % divisor == 0
        } else {
            return false
        }
    }
}

func sum(numbers: [Int]) -> Int {
    return numbers.reduce(0, +)
}

func sum(strings: [String]) -> Int {
    return sum(numbers: strings.compactMap { Int($0) })
}

func sum(input: [Any]) -> Int {
    return sum(numbers: input.compactMap {
        if let number = $0 as? Int {
            return number
        } else if let string = $0 as? String {
            return Int(string)
        } else {
            return nil
        }
    })
}

func product(numbers: [Int]) -> Int {
    return numbers.reduce(1, *)
}

func product(strings: [String]) -> Int {
    return product(numbers: strings.compactMap { Int($0) })
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of integers only for ones that are divisible by given divisor
// filterByDivisibility(numbers: [] as [Int], divisor: 1) == [] as [Int]
// filterByDivisibility(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 3) == [3, 6, 9]
func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

// Filter an input array of strings and integers only for ones that are divisible by given divisor
// filterByDivisibility(input: [] as [Any], divisor: 1) == [] as [Any]
// filterByDivisibility(input: ["abc", 1, 2, 3, 4, "def", 5, 6, 7, "ghi", 8, 9, "jkl", 10], divisor: 3) == ["abc", 3, "def", 6, "ghi", 9]
func filterByDivisibility(input: [Any], divisor: Int) -> [Any] {
    return input.filter {
        if let number = $0 as? Int {
            return number % divisor == 0
        } else if let string = $0 as? String {
            return Int(string)!= nil && Int(string)! % divisor == 0
        } else {
            return false
        }
    }
}

// Return the sum of all numbers in an input array of integers
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 55
func sum(numbers: [Int]) -> Int {
    return numbers.reduce(0, +)
}

// Return the sum of all numbers in an input array of strings that can be converted to integers
// sum(strings: [] as [String]) == 0
// sum(strings: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]) == 55
func sum(strings: [String]) -> Int {
    return sum(numbers: strings.compactMap { Int($0) })
}

// Return the sum of all numbers in an input array of integers and strings that can be converted to integers
// sum(input: [] as [Any]) == 0
// sum(input: ["1", 2, "3", 4, "5", 6, "7", 8, "9", 10, "abc"]) == 55
func sum(input: [Any]) -> Int {
    return sum(numbers: input.compactMap {
        if let number = $0 as? Int {
            return number
        } else if let string = $0 as? String {
            return Int(string)
        } else {
            return nil
        }
    })
}

// Return the product of all numbers in an input array of integers
// product(numbers: [] as [Int]) == 1
// product(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 3628800
func product(numbers: [Int]) -> Int {
    return numbers.reduce(1, *)
}

// Return the product of all numbers in an input array of strings that can be converted to integers
// product(strings: [] as [String]) == 1
// product(strings: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]) == 3628800
func product(strings: [String]) -> Int {
    return product(numbers: strings.compactMap { Int($0) })
}

// Return the product of all numbers in an input array of integers and strings that can be converted to integers
// product(input: [] as [Any]) == 1
// product(input: ["1", 2, "3", 4, "5", 6, "7", 8, "9", 10, "abc"]) == 

func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

func filterByKeyAndValue(dictionaries: [Dictionary<String, Int>], key: String, value: Int) -> [Dictionary<String, Int>] {
    return dictionaries.filter { $0[key] == value }
}

func extractDigits(strings: [String]) -> [Int] {
    return strings.compactMap { Int($0) }
}

func extractKeyValues(strings: [String]) -> [Dictionary<String, Int>] {
    return strings.compactMap {
        let components = $0.components(separatedBy: ":")
        guard components.count == 2, let key = Int(components[0]), let value = Int(components[1]) else {
            return nil
        }
        return [components[0] : value]
    }
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of integers only for ones that are divisible by given divisor
// filterByDivisibility(numbers: [] as [Int], divisor: 2) == [] as [Int]
// filterByDivisibility(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 3) == [3, 6, 9]
func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

// Filter an input array of dictionaries only for ones that have a given key and value
// filterByKeyAndValue(dictionaries: [] as [Dictionary<String, Int>], key: "key", value: 1) == [] as [Dictionary<String, Int>]
// filterByKeyAndValue(dictionaries: [["key": 1, "value": 2], ["key": 2, "value": 3], ["key": 3, "value": 4]], key: "key", value: 2) == [["key": 2, "value": 3]]
func filterByKeyAndValue(dictionaries: [Dictionary<String, Int>], key: String, value: Int) -> [Dictionary<String, Int>] {
    return dictionaries.filter { $0[key] == value }
}

// Return an array of integers from an input array of strings, where each string contains only digits
// extractDigits(strings: [] as [String]) == [] as [Int]
// extractDigits(strings: ["abc123", "1a2b3", "789", "0"]) == [123, 123, 789, 0]
func extractDigits(strings: [String]) -> [Int] {
    return strings.compactMap { Int($0) }
}

// Return an array of dictionaries from an input array of strings, where each string contains key-value pairs
// in the format "key:value". The function should handle cases where the strings are not in the correct format
// and should return an empty array in those cases.
// extractKeyValues(strings: [] as [String]) == [] as [Dictionary<String, Int>]
// extractKeyValues(strings: ["key1:1", "key2:2", "key3:3", "key4:4", "key5:5", "key6:6", "key7:7", "key8:8", "key9:9", "key10:10"]) == [["key1": 1], ["key2": 2], ["key3": 3], ["key4": 4], ["key5": 5], ["key6": 6], ["key7": 7], ["key8": 8], ["key9": 9], ["key10": 10]]
func extractKeyValues(strings: [String]) -> [Dictionary<String, Int>] {
    return strings.compactMap {
        let components = $0.components(separatedBy: ":")
        guard components.count == 2, let key = Int(components[0]), let value = Int(components[1]) else {
            return nil
        }
        return [components[0] : value]
    }
}

// Return an array of strings from an input array of dictionaries, where each dictionary contains only key-value
// pairs in the format "key:value". The function should handle cases where the dictionaries are not in the correct format
// and should return an empty array in those cases.
// extractKeyValuePairs(dictionaries: [] as [Dictionary<String, Int>]) == [] as [String]
// extractKeyValuePairs(dictionaries: [["key1": 1], ["key2": 2], ["key3": 3], ["key4": 4], ["key5": 5], ["key6": 6], ["key7": 7], ["key8": 8], ["key9": 9], ["key10": 10]]) == ["key1:1", "key2:2", "key3:3", "key4:4", "key5:5", "key6:6", "key7:7", "key8:8", "key9:9", "key10:10"]
func extractKeyValuePairs(dictionaries: [Dictionary<String, Int>])

func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstringAndLength(strings: [String], substring: String, length: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) && string.count > length {
            result.append(string)
        }
    }
    return result
}

func filterBySubstringLengthAndCapital(strings: [String], substring: String, length: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) && string.count > length && string.first!.isUppercase {
            result.append(string)
        }
    }
    return result
}

func addPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(prefix + string)
    }
    return result
}

func addSuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string + suffix)
    }
    return result
}

func addPrefixSuffix(strings: [String], prefix: String, suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(prefix + string + suffix)
    }
    return result
}

func removeCharacter(strings: [String], character: Character) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string.replacingOccurrences(of: String(character), with: ""))
    }
    return result
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain given substring and are longer than given length
// filterBySubstringAndLength(strings: [] as [String], substring: "a", length: 0) == [] as [String]
// filterBySubstringAndLength(strings: ["abc", "bacd", "cde", "array"], substring: "a", length: 3) == ["abc", "array"]
func filterBySubstringAndLength(strings: [String], substring: String, length: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) && string.count > length {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain given substring, are longer than given length,
// and start with a capital letter
// filterBySubstringLengthAndCapital(strings: [] as [String], substring: "a", length: 0) == [] as [String]
// filterBySubstringLengthAndCapital(strings: ["abc", "bacd", "cde", "array"], substring: "a", length: 3) == ["abc"]
func filterBySubstringLengthAndCapital(strings: [String], substring: String, length: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) && string.count > length && string.first!.isUppercase {
            result.append(string)
        }
    }
    return result
}

// Return a new array of strings with the given prefix added to the beginning of each string in the input array
// addPrefix(strings: [] as [String], prefix: "") == [] as [String]
// addPrefix(strings: ["abc", "bacd", "cde", "array"], prefix: "f") == ["fabc", "fbacd", "fcde", "farray"]
func addPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(prefix + string)
    }
    return result
}

// Return a new array of strings with the given suffix added to the end of each string in the input array
// addSuffix(strings: [] as [String], suffix: "") == [] as [String]
// addSuffix(strings: ["abc", "bacd", "cde", "array"], suffix: "f") == ["abcf", "bacdf", "cdef", "arrayf"]
func addSuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string + suffix)
    }
    return result
}

// Return a new array of strings with the given prefix and suffix added to each string in the input array
// addPrefixSuffix(strings: [] as [String], prefix: "", suffix: "") == [] as [String]
// addPrefixSuffix(strings: ["abc", "bacd", "cde", "array"], prefix: "f", suffix: "f") == ["fabc", "fbacd", "fcde", "farray"]
func addPrefixSuffix(strings: [String], prefix: String, suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(prefix + string + suffix)
    }
    return result
}

// Return a new array of strings with the given character removed from each string in the input array
// removeCharacter(strings: [] as [String], character: "") == [] as [String]
// removeCharacter(strings: ["abc", "bacd", "cde", "array"], character: "a") == ["bc", "bcd", "cde", "ray"]
func removeCharacter(strings: [String], character: Character) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string.replacingOccurrences(of: String(character), with: ""))
    }
    return result
}

// Return a new array of strings with all whitespace characters removed from each string in the input array
// removeWhitespace(strings: [] as [String]) == [] as [String]
// removeWhitespace(strings: ["abc", "bacd", "cde", "array

func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

func filterByKeyAndValue(dictionaries: [Dictionary<String, Int>], key: String, value: Int) -> [Dictionary<String, Int>] {
    return dictionaries.filter { $0[key] == value }
}

func appendToEach(dictionaries: [Dictionary<String, Int>], key: String, value: Int) -> [Dictionary<String, Int>] {
    return dictionaries.map { $0 + [key: value] }
}

func doubleEach(dictionary: [String: Int]) -> [String: Int] {
    return dictionary.mapValues { $0 * 2 }
}

func incrementEach(dictionary: [String: Int]) -> [String: Int] {
    return dictionary.map { key, value in ["kittens-\(key)": value + 1] }.flatMap { $0 }
}

func doubleEachKey(dictionary: [String: Int]) -> [String: Int] {
    return dictionary.mapKeys { "\($0)-awesome" }
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of integers only for ones that are divisible by given divisor
// filterByDivisibility(numbers: [] as [Int], divisor: 2) == [] as [Int]
// filterByDivisibility(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 3) == [3, 6, 9]
func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

// Filter an input array of dictionaries only for ones that have a given key and value
// filterByKeyAndValue(dictionaries: [] as [Dictionary<String, Int>], key: "a", value: 1) == [] as [Dictionary<String, Int>]
// filterByKeyAndValue(dictionaries: [["a": 1, "b": 2], ["a": 2, "b": 3], ["a": 3, "b": 4]], key: "a", value: 2) == [["a": 2, "b": 3]]
func filterByKeyAndValue(dictionaries: [Dictionary<String, Int>], key: String, value: Int) -> [Dictionary<String, Int>] {
    return dictionaries.filter { $0[key] == value }
}

// Return a new array of dictionaries where each one has a new key-value pair appended
// appendToEach(dictionaries: [] as [Dictionary<String, Int>], key: "a", value: 1) == [] as [Dictionary<String, Int>]
// appendToEach(dictionaries: [["a": 1, "b": 2], ["a": 2, "b": 3], ["a": 3, "b": 4]], key: "a", value: 2) == [["a": 1, "b": 2, "a": 2], ["a": 2, "b": 3, "a": 2], ["a": 3, "b": 4, "a": 2]]
func appendToEach(dictionaries: [Dictionary<String, Int>], key: String, value: Int) -> [Dictionary<String, Int>] {
    return dictionaries.map { $0 + [key: value] }
}

// Return a new dictionary where each key-value pair is doubled
// doubleEach(dictionary: [:]) == [:]
// doubleEach(dictionary: ["a": 1, "b": 2, "c": 3]) == ["a": 2, "b": 4, "c": 6]
func doubleEach(dictionary: [String: Int]) -> [String: Int] {
    return dictionary.mapValues { $0 * 2 }
}

// Return a new dictionary where each key is prefixed with "kittens-" and each value is incremented by 1
// incrementEach(dictionary: [:]) == [:]
// incrementEach(dictionary: ["a": 1, "b": 2, "c": 3]) == ["kittens-a": 2, "kittens-b": 3, "kittens-c": 4]
func incrementEach(dictionary: [String: Int]) -> [String: Int] {
    return dictionary.map { key, value in ["kittens-\(key)": value + 1] }.flatMap { $0 }
}

// Return a new dictionary where each key is suffixed with "-awesome" and each value is doubled
// doubleEachKey(dictionary: [:]) == [:]
// doubleEachKey(dictionary: ["a": 1, "b": 2, "c": 3]) == ["a-awesome": 2, "b-awesome": 4, "c-awesome": 6]
func doubleEachKey(dictionary: [String: Int]) -> [String: Int] {
    return dictionary.mapKeys { "\($0)-awesome" }
}

// Return a new dictionary where each value is suffixed with "ly" and each key is doubled
// doubleEachValue(dictionary: [:]) == [:]
// doubleEachValue(dictionary: ["a": 1, "b": 2, "c": 3]) == ["a": 2, "b": 4, "c":

func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    var result = [Int]()
    for number in numbers {
        if number % divisor == 0 {
            result.append(number)
        }
    }
    return result
}

func filterByDivisibility(input: [Any], divisor: Int) -> [Any] {
    var result = [Any]()
    for item in input {
        if let number = item as? Int {
            if number % divisor == 0 {
                result.append(number)
            }
        } else if let string = item as? String {
            if Int(string)!= nil && Int(string)! % divisor == 0 {
                result.append(string)
            }
        }
    }
    return result
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of integers only for ones that are divisible by given divisor
// filterByDivisibility(numbers: [] as [Int], divisor: 1) == [] as [Int]
// filterByDivisibility(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 3) == [3, 6, 9]
func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    var result = [Int]()
    for number in numbers {
        if number % divisor == 0 {
            result.append(number)
        }
    }
    return result
}

// Filter an input array of strings and integers only for ones that are divisible by given divisor
// filterByDivisibility(input: [] as [Any], divisor: 1) == [] as [Any]
// filterByDivisibility(input: ["abc", 1, "def", 2, "ghi", 3, "jkl", 4, "mno", 5], divisor: 3) == ["abc", "def", "ghi", "jkl", "mno"]
func filterByDivisibility(input: [Any], divisor: Int) -> [Any] {
    var result = [Any]()
    for item in input {
        if let number = item as? Int {
            if number % divisor == 0 {
                result.append(number)
            }
        } else if let string = item as? String {
            if Int(string)!= nil && Int(string)! % divisor == 0 {
                result.append(string)
            }
        }
    }
    return result
}

// Filter an input array of strings and integers only for ones that are divisible by given divisor
// filterByDivisibility(input: [] as [Any], divisor: 1) == [] as [Any]
// filterByDivisibility(input: ["abc", 1, "def", 2, "ghi", 3, "jkl", 4, "mno", 5], divisor: 3) == ["abc", "def", "ghi", "jkl", "mno"]
func filterByDivisibility(input: [Any], divisor: Int) -> [Any] {
    var result = [Any]()
    for item in input {
        if let number = item as? Int {
            if number % divisor == 0 {
                result.append(number)
            }
        } else if let string = item as? String {
            if Int(string)!= nil && Int(string)! % divisor == 0 {
                result.append(string)
            }
        }
    }
    return result
}

// Filter an input array of strings and integers only for ones that are divisible by given divisor
// filterByDivisibility(input: [] as [Any], divisor: 1) == [] as [Any]
// filterByDivisibility(input: ["abc", 1, "def", 2, "ghi", 3, "jkl", 4, "mno", 5], divisor: 3) == ["abc", "def", "ghi", "jkl", "mno"]
func filterByDivisibility(input: [Any], divisor: Int) -> [Any] {
    var result = [Any]()
    for item in input {
        if let number = item as? Int {
            if number % divisor == 0 {
                result.append(number)
            }
        } else if let string = item as? String {
            if Int(string)!= nil && Int(string)! % divisor == 0 {
                result.append(string)
            }
        }
    }
    return result
}

// Filter an input array of strings and integers only for ones that are divisible by given divisor
// filterByDivisibility(input: [] as [Any], divisor: 1) == [] as [Any]
// filterByDivisibility(input: ["abc", 1, "def", 2, "ghi", 3, "jkl", 4, "mno", 5], divisor: 3) == ["abc", "def", "ghi", "jkl", "mno"]
func

func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

func filterByDivisibility(input: [Any], divisor: Int) -> [Any] {
    return input.filter {
        if let number = $0 as? Int {
            return number % divisor == 0
        } else if let string = $0 as? String {
            return Int(string)!= nil && Int(string)! % divisor == 0
        }
        return false
    }
}

func getDivisibleNumbers(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

func getDivisibleStrings(strings: [String], divisor: Int) -> [String] {
    return strings.filter { Int($0)!= nil && Int($0)! % divisor == 0 }
}

func getLetterStarts(dictionary: [String: Int], letter: String) -> [String: Int] {
    return dictionary.filter { $0.key.hasPrefix(letter) }
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of integers only for ones that are divisible by given divisor
// filterByDivisibility(numbers: [] as [Int], divisor: 1) == [] as [Int]
// filterByDivisibility(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 3) == [3, 6, 9]
func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

// Filter an input array of strings and integers only for ones that are divisible by given divisor
// filterByDivisibility(input: [] as [Any], divisor: 1) == [] as [Any]
// filterByDivisibility(input: ["abc", 1, 2, 3, 4, "5", 6, "7", 8, 9, "10"], divisor: 3) == ["abc", 3, 6, "7", 9]
func filterByDivisibility(input: [Any], divisor: Int) -> [Any] {
    return input.filter {
        if let number = $0 as? Int {
            return number % divisor == 0
        } else if let string = $0 as? String {
            return Int(string)!= nil && Int(string)! % divisor == 0
        }
        return false
    }
}

// Return a new array of integers containing only the numbers from the input array that are divisible by given divisor
// getDivisibleNumbers(numbers: [] as [Int], divisor: 1) == [] as [Int]
// getDivisibleNumbers(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 3) == [3, 6, 9]
func getDivisibleNumbers(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

// Return a new array of strings containing only the strings from the input array that are divisible by given divisor
// getDivisibleStrings(strings: [] as [String], divisor: 1) == [] as [String]
// getDivisibleStrings(strings: ["abc", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10"], divisor: 3) == ["abc", "3", "6", "9"]
func getDivisibleStrings(strings: [String], divisor: Int) -> [String] {
    return strings.filter { Int($0)!= nil && Int($0)! % divisor == 0 }
}

// Return a new dictionary with only the key-value pairs from the input dictionary that have a key that starts with a given letter
// getLetterStarts(dictionary: [:], letter: "a") == [: ]
// getLetterStarts(dictionary: ["abc": 1, "bcd": 2, "cde": 3, "def": 4, "efg": 5, "fgh": 6, "ghi": 7, "hji": 8, "ijk": 9, "jkl": 10], letter: "b") == ["bcd": 2, "cde": 3, "def": 4, "efg": 5, "fgh": 6, "ghi": 7, "hji": 8, "ijk": 9, "jkl": 10]
func getLetterStarts(dictionary: [String: Int], letter: String) -> [String: Int] {
    return dictionary.filter { $0.key.hasPrefix(letter) }
}

// Return a new dictionary with only the key-value pairs from the input dictionary that have a key that ends with a given letter
// getLetterEnds(dictionary: [:], letter: "a") == [: ]
// getLetterEnds(dictionary: ["abc": 1, "bcd": 2, "cde": 3, "def": 4, "efg": 5, "fgh": 6, "ghi": 7, "hji":

func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

func filterByKeyAndValue(dictionaries: [Dictionary<String, Int>], key: String, value: Int) -> [Dictionary<String, Int>] {
    return dictionaries.filter { $0[key] == value }
}

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) }
}

func filterBySuffix(strings: [String], suffix: String) -> [String] {
    return strings.filter { $0.hasSuffix(suffix) }
}

func filterBySubstringAnyPosition(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

func filterBySubstringBeginning(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.hasPrefix(substring) }
}

func filterBySubstringEnd(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.hasSuffix(substring) }
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of integers only for ones that are divisible by given divisor
// filterByDivisibility(numbers: [] as [Int], divisor: 2) == [] as [Int]
// filterByDivisibility(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 3) == [3, 6, 9]
func filterByDivisibility(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

// Filter an input array of dictionaries only for ones that have a given key and value
// filterByKeyAndValue(dictionaries: [] as [Dictionary<String, Int>], key: "a", value: 1) == [] as [Dictionary<String, Int>]
// filterByKeyAndValue(dictionaries: [["a": 1, "b": 2], ["a": 2, "b": 3], ["a": 3, "b": 4], ["a": 4, "b": 5]], key: "a", value: 2) == [["a": 2, "b": 3], ["a": 3, "b": 4]]
func filterByKeyAndValue(dictionaries: [Dictionary<String, Int>], key: String, value: Int) -> [Dictionary<String, Int>] {
    return dictionaries.filter { $0[key] == value }
}

// Filter an input array of strings only for ones that start with a given prefix
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bacd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) }
}

// Filter an input array of strings only for ones that end with a given suffix
// filterBySuffix(strings: [] as [String], suffix: "a") == [] as [String]
// filterBySuffix(strings: ["abc", "bacd", "cde", "array"], suffix: "a") == ["cde"]
func filterBySuffix(strings: [String], suffix: String) -> [String] {
    return strings.filter { $0.hasSuffix(suffix) }
}

// Filter an input array of strings only for ones that contain a given substring in any position
// filterBySubstringAnyPosition(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringAnyPosition(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstringAnyPosition(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain a given substring at the beginning of a string
// filterBySubstringBeginning(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringBeginning(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc"]
func filterBySubstringBeginning(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.hasPrefix(substring) }
}

// Filter an input array of strings only for ones that contain a given substring at the end of a string
// filterBySubstringEnd(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringEnd(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["cde", "array"]
func filterBySubstringEnd(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.hasSuffix(substring) }
}

// Filter an input array of dictionaries only for ones that have a given key and value, regardless of case
// filterByKeyAndValueCaseInsensitive(dictionaries: [] as [Dictionary<String, Int>], key: "a", value

func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"],

func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

func filterBySubstringCaseInsensitive(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().contains(substring.lowercased()) }
}

func filterBySubstringCaseInsensitiveAndWhitespaceTrimmed(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().trimmingCharacters(in:.whitespaces).contains(substring.lowercased().trimmingCharacters(in:.whitespaces)) }
}

func filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemoved(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation).contains(substring.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation)) }
}

func filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemovedMultipleOccurrencesRemoved(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation).components(separatedBy: substring.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation)).count == 1 }
}

func filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemovedMultipleOccurrencesRemovedOverlapping(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation).components(separatedBy: substring.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation)).filter { $0!= substring.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation) }.count == 1 }
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring, ignoring case
// filterBySubstringCaseInsensitive(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringCaseInsensitive(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "array"]
func filterBySubstringCaseInsensitive(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().contains(substring.lowercased()) }
}

// Filter an input array of strings only for ones that contain given substring, ignoring case and whitespace
// filterBySubstringCaseInsensitiveAndWhitespaceTrimmed(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringCaseInsensitiveAndWhitespaceTrimmed(strings: ["abc", " bacd ", " cde", "array "], substring: "a") == ["abc", "array"]
func filterBySubstringCaseInsensitiveAndWhitespaceTrimmed(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().trimmingCharacters(in:.whitespaces).contains(substring.lowercased().trimmingCharacters(in:.whitespaces)) }
}

// Filter an input array of strings only for ones that contain given substring, ignoring case, whitespace and punctuation
// filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemoved(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemoved(strings: ["abc", " bacd ", " cde", "array."], substring: "a") == ["abc", "array"]
func filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemoved(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation).contains(substring.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation)) }
}

// Filter an input array of strings only for ones that contain given substring, ignoring case, whitespace, punctuation and multiple occurrences
// filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemovedMultipleOccurrencesRemoved(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemovedMultipleOccurrencesRemoved(strings: ["abc", " bacd ", " cde", "array.", "array"], substring: "a") == ["abc", "array"]
func filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemovedMultipleOccurrencesRemoved(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation).components(separatedBy: substring.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation)).count == 1 }
}

// Filter an input array of strings only for ones that contain given substring, ignoring case, whitespace, punctuation, multiple occurrences and overlapping occurrences
// filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemovedMultipleOccurrencesRemovedOverlapping(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemovedMultipleOccurrencesRemovedOverlapping(strings: ["abc", " bacd ", " cde", "array.", "array"], substring: "a") == ["abc", "array"]
func filterBySubstringCaseInsensitiveAndWhitespaceTrimmedPunctuationRemovedMultipleOccurrencesRemovedOverlapping(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation).components(separatedBy: substring.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation)).filter { $0!= substring.lowercased().trimmingCharacters(in:.whitespacesAndPunctuation) }.count == 1 }
}

// Filter an input array

func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

func filterBySubstringAndLength(strings: [String], substring: String, length: Int) -> [String] {
    return strings.filter { $0.contains(substring) && $0.count > length }
}

func filterBySubstringLengthAndCharacterCount(strings: [String], substring: String, length: Int, characterCount: Int) -> [String] {
    return strings.filter { $0.contains(substring) && $0.count > length && $0.filter { $0 == substring }.count >= characterCount }
}

func filterBySubstringLengthCharacterCountAndNoRepeatedCharacters(strings: [String], substring: String, length: Int, characterCount: Int) -> [String] {
    return strings.filter {
        $0.contains(substring) &&
        $0.count > length &&
        $0.filter { $0 == substring }.count >= characterCount &&
        $0.filter { $0 == substring }.count == $0.count
    }
}

func filterBySubstringLengthCharacterCountNoRepeatedCharactersNotStartWithVowel(strings: [String], substring: String, length: Int, characterCount: Int) -> [String] {
    return strings.filter {
        $0.contains(substring) &&
        $0.count > length &&
        $0.filter { $0 == substring }.count >= characterCount &&
        $0.filter { $0 == substring }.count == $0.count &&
       !"aeiou".contains($0.prefix(1).lowercased())
    }
}

```swift
// Filter an input array of strings only for ones that contain given substring
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bacd", "cde", "array"], substring: "a") == ["abc", "bacd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    return strings.filter { $0.contains(substring) }
}

// Filter an input array of strings only for ones that contain given substring and are longer than given length
// filterBySubstringAndLength(strings: [] as [String], substring: "a", length: 1) == [] as [String]
// filterBySubstringAndLength(strings: ["abc", "bacd", "cde", "array"], substring: "a", length: 1) == ["abc", "array"]
func filterBySubstringAndLength(strings: [String], substring: String, length: Int) -> [String] {
    return strings.filter { $0.contains(substring) && $0.count > length }
}

// Filter an input array of strings only for ones that contain given substring, are longer than given length,
// and have at least given number of characters.
// filterBySubstringLengthAndCharacterCount(strings: [] as [String], substring: "a", length: 1, characterCount: 1) == [] as [String]
// filterBySubstringLengthAndCharacterCount(strings: ["abc", "bacd", "cde", "array"], substring: "a", length: 1, characterCount: 1) == ["abc"]
func filterBySubstringLengthAndCharacterCount(strings: [String], substring: String, length: Int, characterCount: Int) -> [String] {
    return strings.filter { $0.contains(substring) && $0.count > length && $0.filter { $0 == substring }.count >= characterCount }
}

// Filter an input array of strings only for ones that contain given substring, are longer than given length,
// have at least given number of characters, and do not contain any repeated characters.
// filterBySubstringLengthCharacterCountAndNoRepeatedCharacters(strings: [] as [String], substring: "a", length: 1, characterCount: 1) == [] as [String]
// filterBySubstringLengthCharacterCountAndNoRepeatedCharacters(strings: ["abc", "bacd", "cde", "array"], substring: "a", length: 1, characterCount: 1) == ["abc"]
func filterBySubstringLengthCharacterCountAndNoRepeatedCharacters(strings: [String], substring: String, length: Int, characterCount: Int) -> [String] {
    return strings.filter {
        $0.contains(substring) &&
        $0.count > length &&
        $0.filter { $0 == substring }.count >= characterCount &&
        $0.filter { $0 == substring }.count == $0.count
    }
}

// Filter an input array of strings only for ones that contain given substring, are longer than given length,
// have at least given number of characters, do not contain any repeated characters, and do not start with a vowel.
// filterBySubstringLengthCharacterCountNoRepeatedCharactersNotStartWithVowel(strings: [] as [String], substring: "a", length: 1, characterCount: 1) == [] as [String]
// filterBySubstringLengthCharacterCountNoRepeatedCharactersNotStartWithVowel(strings: ["abc", "bacd", "cde", "array"], substring: "a", length: 1, characterCount: 1) == ["array"]
func filterBySubstringLengthCharacterCountNoRepeatedCharactersNotStartWithVowel(strings: [String], substring: String, length: Int, characterCount: Int) -> [String] {
    return strings.filter {
        $0.contains(substring) &&
        $0.count > length &&
        $0.filter { $0 == substring }.count >= characterCount &&
        $0.filter { $0 == substring }.count == $0.count &&
       !"aeiou".contains($0.prefix(1).lowercased())
    }
}

// Filter an input array of strings only for ones that contain given substring, are longer than given length,
// have at least given number of characters, do not contain any repeated characters, start with a vowel,
// and are in lexicographically increasing order.
// filterBySubstringLengthCharacterCountNoRepeatedCharactersStartWithVowelInLexicographicallyIncreasingOrder(strings: [] as [String], substring: "a", length: 1, characterCount: 1) == [] as [String]
// filterBySubstringLengthCharacterCountNoRepeatedCharactersStartWithVowelInLexicographicallyIncreasingOrder(strings: ["abc", "bacd", "cde

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

// Test Cases
sumProduct(numbers: []) == (0, 1)
sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
```

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

sumProduct(numbers: []) // (0, 1)
sumProduct(numbers: [1, 2, 3, 4]) // (10, 24)
```

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

// Test cases
sumProduct(numbers: []) // (0, 1)
sumProduct(numbers: [1, 2, 3, 4]) // (10, 24)
```

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    for number in numbers {
        sum += number
        product *= number
    }
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    for number in numbers {
        sum += number
        product *= number
    }
    return (sum, product)
}

// Test Cases
sumProduct(numbers: []) // (0, 1)
sumProduct(numbers: [1, 2, 3, 4]) // (10, 24)
```

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

sumProduct(numbers: [])
sumProduct(numbers: [1, 2, 3, 4])
```

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

// Test Cases
sumProduct(numbers: []) == (0, 1)
sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
```

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

sumProduct(numbers: [])
sumProduct(numbers: [1, 2, 3, 4])
```

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

// Test Cases
sumProduct(numbers: []) == (0, 1)
sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
```

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    
    for number in numbers {
        sum += number
        product *= number
    }
    
    return (sum, product)
}

sumProduct(numbers: [1, 2, 3, 4])
sumProduct(numbers: [])
```

func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    for number in numbers {
        sum += number
        product *= number
    }
    return (sum, product)
}

```swift
// For a given array of integers, return a tuple consisting of a sum and a product of all the integers in an array.
// Empty sum should be equal to 0 and empty product should be equal to 1.
// sumProduct(numbers: [] as [Int]) == (0, 1)
// sumProduct(numbers: [1, 2, 3, 4]) == (10, 24)
func sumProduct(numbers: [Int]) -> (Int, Int) {
    var sum = 0
    var product = 1
    for number in numbers {
        sum += number
        product *= number
    }
    return (sum, product)
}

let numbers = [1, 2, 3, 4]
let (sum, product) = sumProduct(numbers: numbers)
print("Sum: \(sum), Product: \(product)")
```

func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

func rollingSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(sum)
    }
    return result
}

func rollingAverage(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(Double(sum) / Double(i))
    }
    return result
}

func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    var sumSquared = 0
    for i in numbers {
        sum += i
        sumSquared += i * i
        result.append(sqrt(Double(sumSquared - sum * sum) / Double(i)))
    }
    return result
}

func rollingVariance(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    var sumSquared = 0
    for i in numbers {
        sum += i
        sumSquared += i * i
        result.append(Double(sumSquared - sum * sum) / Double(i))
    }
    return result
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 3]
func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum element found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of rolling average element found until given moment
// in the sequence.
// rollingAverage(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 2, 2, 2, 3, 3]
func rollingAverage(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(Double(sum) / Double(i))
    }
    return result
}

// From a given array of integers, generate an array of rolling standard deviation element found until given moment
// in the sequence.
// rollingStandardDeviation(numbers: [1, 2, 3, 2, 3, 4, 2]) == [0, 0.4, 0.7071067811865476, 0.7071067811865476, 0.7071067811865476, 1.1581139000331498, 1.1581139000331498]
func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    var sumSquared = 0
    for i in numbers {
        sum += i
        sumSquared += i * i
        result.append(sqrt(Double(sumSquared - sum * sum) / Double(i)))
    }
    return result
}

// From a given array of integers, generate an array of rolling variance element found until given moment
// in the sequence.
// rollingVariance(numbers: [1, 2, 3, 2, 3, 4, 2]) == [0, 0.4, 0.7071067811865476, 0.7071067811865476, 0.7071067811865476, 1.1581139000331498, 1.1581139000331498]
func rollingVariance(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    var sumSquared = 0
    for i in numbers {
        sum += i
        sumSquared += i * i
        result.append(Double(sumSquared - sum * sum) / Double(i))
    }
    return result
}

// From a given array of integers, generate an array of moving average element found until given moment
// in the sequence.
// movingAverage

func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

func rollingSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(sum)
    }
    return result
}

func cumulativeSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    result.append(sum)
    for i in numbers {
        sum += i
        result.append(sum)
    }
    return result
}

func cumulativeProduct(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var product = 1
    result.append(product)
    for i in numbers {
        product *= i
        result.append(product)
    }
    return result
}

func cumulativeMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in numbers {
        max = max(max, i)
        result.append(max)
    }
    return result
}

func cumulativeMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in numbers {
        min = min(min, i)
        result.append(min)
    }
    return result
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 3]
func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum found until given moment in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of cumulative sum found until given moment in the sequence.
// cumulativeSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 15]
func cumulativeSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    result.append(sum)
    for i in numbers {
        sum += i
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of cumulative product found until given moment in the sequence.
// cumulativeProduct(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 6, 12, 18, 24, 48]
func cumulativeProduct(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var product = 1
    result.append(product)
    for i in numbers {
        product *= i
        result.append(product)
    }
    return result
}

// From a given array of integers, generate an array of cumulative maximum element found until given moment
// in the sequence.
// cumulativeMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func cumulativeMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in numbers {
        max = max(max, i)
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of cumulative minimum element found until given moment
// in the sequence.
// cumulativeMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 3]
func cumulativeMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in numbers {
        min = min(min, i)
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of cumulative sum found until given moment in the sequence.
// cumulativeSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 15]
func cumulativeSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0

func rollingMax(numbers: [Int]) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

func rollingMax(numbers: [Int], window: Int) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        if i >= window {
            max = max(max, numbers[i - window])
        }
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int], window: Int) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        if i >= window {
            min = min(min, numbers[i - window])
        }
        result.append(min)
    }
    return result
}

func rollingSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

func rollingSum(numbers: [Int], window: Int) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        if i >= window {
            sum -= numbers[i - window]
        }
        result.append(sum)
    }
    return result
}

func cumulativeSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 3]
func rollingMin(numbers: [Int]) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int], window: Int) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        if i >= window {
            max = max(max, numbers[i - window])
        }
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 3]
func rollingMin(numbers: [Int], window: Int) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        if i >= window {
            min = min(min, numbers[i - window])
        }
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum element found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum element found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2], window: 3) == [3, 6, 9, 6, 9, 12, 9]
func rollingSum(numbers: [Int], window: Int) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        if i >= window {
            sum -= numbers[i - window]
        }
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of cumulative sum element found until given moment
// in the sequence.
// cumulativeSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 15]
func cumulativeSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of cumulative sum element found until given moment
// in

func rollingMax(numbers: [Int]) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

func rollingMax(numbers: [Int], window: Int) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        if i >= window {
            max = max(max, numbers[i - window])
        }
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int], window: Int) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        if i >= window {
            min = min(min, numbers[i - window])
        }
        result.append(min)
    }
    return result
}

func rollingSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

func rollingSum(numbers: [Int], window: Int) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        if i >= window {
            sum -= numbers[i - window]
        }
        result.append(sum)
    }
    return result
}

func cumulativeSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 2]
func rollingMin(numbers: [Int]) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int], window: Int) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        if i >= window {
            max = max(max, numbers[i - window])
        }
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 2]
func rollingMin(numbers: [Int], window: Int) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        if i >= window {
            min = min(min, numbers[i - window])
        }
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum element found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum element found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int], window: Int) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        if i >= window {
            sum -= numbers[i - window]
        }
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of cumulative sum element found until given moment
// in the sequence.
// cumulativeSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 15]
func cumulativeSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of cumulative sum element found until given moment
// in the sequence.

func rollingMax(numbers: [Int]) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

func rollingMax(numbers: [Int], windowSize: Int) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        if i >= windowSize {
            max = max(max, numbers[i - windowSize])
        }
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int], windowSize: Int) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        if i >= windowSize {
            min = min(min, numbers[i - windowSize])
        }
        result.append(min)
    }
    return result
}

func rollingSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

func rollingSum(numbers: [Int], windowSize: Int) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        if i >= windowSize {
            sum -= numbers[i - windowSize]
        }
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

func cumulativeSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 3]
func rollingMin(numbers: [Int]) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int], windowSize: Int) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        if i >= windowSize {
            max = max(max, numbers[i - windowSize])
        }
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 3]
func rollingMin(numbers: [Int], windowSize: Int) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        if i >= windowSize {
            min = min(min, numbers[i - windowSize])
        }
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum element found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum element found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2], windowSize: 3) == [3, 5, 8, 8, 11, 13, 13]
func rollingSum(numbers: [Int], windowSize: Int) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        if i >= windowSize {
            sum -= numbers[i - windowSize]
        }
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of cumulative sum element found until given moment
// in the sequence.
// cumulativeSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 15]
func cumulativeSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array

func rollingMax(numbers: [Int]) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

func rollingSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

func rollingAverage(numbers: [Int]) -> [Double] {
    let sums = rollingSum(numbers: numbers)
    let max = max(1, numbers.count)
    return sums.map { Double($0) / Double(max) }
}

func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    let averages = rollingAverage(numbers: numbers)
    let squaredDiffs = zip(averages, numbers).map { pow(($0 - $1), 2) }
    let sums = rollingSum(numbers: squaredDiffs)
    let max = max(1, numbers.count)
    return sums.map { Double($0) / Double(max) }
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 3]
func rollingMin(numbers: [Int]) -> [Int] {
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int]) -> [Int] {
    var sum = 0
    var result = [sum]
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of rolling average found until given moment
// in the sequence.
// rollingAverage(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 2, 2.5, 2.5, 3, 3]
func rollingAverage(numbers: [Int]) -> [Double] {
    let sums = rollingSum(numbers: numbers)
    let max = max(1, numbers.count)
    return sums.map { Double($0) / Double(max) }
}

// From a given array of integers, generate an array of rolling standard deviation found until given moment
// in the sequence.
// rollingStandardDeviation(numbers: [1, 2, 3, 2, 3, 4, 2]) == [0, 0.4, 0.7071067811865476, 0.816496580927726, 0.8775824676337209, 0.9092974268256817, 0.9092974268256817]
func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    let averages = rollingAverage(numbers: numbers)
    let squaredDiffs = zip(averages, numbers).map { pow(($0 - $1), 2) }
    let sums = rollingSum(numbers: squaredDiffs)
    let max = max(1, numbers.count)
    return sums.map { Double($0) / Double(max) }
}

// From a given array of integers, generate an array of rolling variance found until given moment
// in the sequence.
// rollingVariance(numbers: [1, 2, 3, 2, 3, 4, 2]) == [0, 0.4, 0.16666666666666663, 0.06666666666666667, 0.03333333333333333, 0.013888888888888888, 0.013888888888888888]
func rollingVariance(numbers: [Int]) -> [Double] {
    let averages = rollingAverage(numbers: numbers)
    let squaredDiffs = zip(averages, numbers).map { pow(($0 - $1), 2) }
    let sums = rollingSum(numbers: squaredDiffs)
    let max = max(1, numbers.count)
    return sum

func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = 0
    for number in numbers {
        if number > max {
            max = number
        }
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = 0
    for number in numbers {
        if number < min {
            min = number
        }
        result.append(min)
    }
    return result
}

func rollingMax(numbers: [Int], window: Int) -> [Int] {
    var result = [Int]()
    var max = 0
    var index = 0
    for number in numbers {
        if index >= window {
            max -= numbers[index - window]
        }
        if number > max {
            max = number
        }
        result.append(max)
        index += 1
    }
    return result
}

func rollingMin(numbers: [Int], window: Int) -> [Int] {
    var result = [Int]()
    var min = 0
    var index = 0
    for number in numbers {
        if index >= window {
            min -= numbers[index - window]
        }
        if number < min {
            min = number
        }
        result.append(min)
        index += 1
    }
    return result
}

func sums(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for number in numbers {
        sum += number
        result.append(sum)
    }
    return result
}

func sums(numbers: [Int], window: Int) -> [Int] {
    var result = [Int]()
    var sum = 0
    var index = 0
    for _ in numbers {
        if index >= window {
            sum -= numbers[index - window]
        }
        sum += numbers[index]
        result.append(sum)
        index += 1
    }
    return result
}

func cumulativeSums(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for number in numbers {
        sum += number
        result.append(sum)
    }
    return result
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = 0
    for number in numbers {
        if number > max {
            max = number
        }
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 2]
func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = 0
    for number in numbers {
        if number < min {
            min = number
        }
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int], window: Int) -> [Int] {
    var result = [Int]()
    var max = 0
    var index = 0
    for number in numbers {
        if index >= window {
            max -= numbers[index - window]
        }
        if number > max {
            max = number
        }
        result.append(max)
        index += 1
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 2]
func rollingMin(numbers: [Int], window: Int) -> [Int] {
    var result = [Int]()
    var min = 0
    var index = 0
    for number in numbers {
        if index >= window {
            min -= numbers[index - window]
        }
        if number < min {
            min = number
        }
        result.append(min)
        index += 1
    }
    return result
}

// Given an array of integers, generate an array of sums of all consecutive elements in the array.
// sums(numbers: [1, 2, 3, 4]) == [1, 3, 6, 10]
func sums(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for number in numbers {
        sum += number
        result.append(sum)
    }
    return result
}

// Given an array of integers, generate an array of sums of all consecutive elements in the array.
// sums(numbers: [1, 2, 3, 4]) == [1, 3, 6, 10]
func sums(numbers: [Int], window: Int) -> [Int] {
    var result = [Int]()
    var sum = 0
    var index = 0
    for _ in numbers {
        if index >= window {
            sum -= numbers[index - window]
        }
        sum += numbers[index]
        result.append(sum)
        index += 1
    }
    return result
}

// Given an array of integers, generate an array of cumulative sums of all consecutive elements in the array.
// cumulativeSums(numbers: [1, 2, 3, 4]) == [1, 3, 6, 10]
func cumulativeSums(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for number in numbers {
        sum += number
        result.append(sum)
    }
    return result
}

// Given an array of integers, generate an array of cumulative sums of all consecutive elements in the array.
// cumulativeSums(numbers: [1, 2, 3, 4]) == [1, 3, 6, 10]
func cumulativeSums(numbers: [Int], window: Int) -> [Int] {
    var result = [Int]()
    var index = 0
    for _ in numbers {
        var sum = 0
        for i in index..<index + window {
            sum += numbers[i]
        }

func rollingMax(numbers: [Int]) -> [Int] {
    guard numbers.count > 0 else { return [] }
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(numbers[i], max)
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    guard numbers.count > 0 else { return [] }
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(numbers[i], min)
        result.append(min)
    }
    return result
}

func rollingSum(numbers: [Int]) -> [Int] {
    guard numbers.count > 0 else { return [] }
    var sum = numbers[0]
    var result = [sum]
    for i in 1..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

func rollingAverage(numbers: [Int]) -> [Double] {
    guard numbers.count > 0 else { return [] }
    let sums = rollingSum(numbers: numbers)
    let divs = rollingMax(numbers: numbers)
    return zip(sums, divs).map { Double($0.0) / Double($0.1) }
}

func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    guard numbers.count > 0 else { return [] }
    let averages = rollingAverage(numbers: numbers)
    let squaredDiffs = zip(averages, numbers).map { pow(($0.0 - $0.1), 2) }
    let sums = rollingSum(numbers: squaredDiffs)
    let divs = rollingMax(numbers: numbers)
    return zip(sums, divs).map { Double($0.0) / Double($0.1) }
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    guard numbers.count > 0 else { return [] }
    var max = numbers[0]
    var result = [max]
    for i in 1..<numbers.count {
        max = max(numbers[i], max)
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 2]
func rollingMin(numbers: [Int]) -> [Int] {
    guard numbers.count > 0 else { return [] }
    var min = numbers[0]
    var result = [min]
    for i in 1..<numbers.count {
        min = min(numbers[i], min)
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum element found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int]) -> [Int] {
    guard numbers.count > 0 else { return [] }
    var sum = numbers[0]
    var result = [sum]
    for i in 1..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of rolling average element found until given moment
// in the sequence.
// rollingAverage(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 2, 2.5, 2.5, 3, 3]
func rollingAverage(numbers: [Int]) -> [Double] {
    guard numbers.count > 0 else { return [] }
    let sums = rollingSum(numbers: numbers)
    let divs = rollingMax(numbers: numbers)
    return zip(sums, divs).map { Double($0.0) / Double($0.1) }
}

// From a given array of integers, generate an array of rolling standard deviation element found until given moment
// in the sequence.
// rollingStandardDeviation(numbers: [1, 2, 3, 2, 3, 4, 2]) == [0, 0.4, 0.7071067811865476, 0.7071067811865476, 0.7071067811865476, 0.7071067811865476, 0.7071067811865476]
func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    guard numbers.count > 0 else { return [] }
    let averages = rollingAverage(numbers: numbers)
    let squaredDiffs = zip(averages, numbers).map { pow(($0.0 - $0.1), 2) }
    let sums = rollingSum(numbers: squaredDiffs)
    let divs = rollingMax(numbers: numbers)
    return zip(sums, divs).map { Double($0.0) / Double($0.1) }
}

// From a given array of integers, generate an array of rolling median element found until given moment
// in the sequence.
// rollingMedian(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 2, 2, 2, 3, 3]
func rollingMedian(numbers: [Int]) -> [Int] {
    guard numbers.count > 0 else { return [] }
    var result = [Int]()
    var sorted = numbers
    while sorted.count > 0 {
        let median = sorted.count % 2 == 0? (sorted[sorted.count / 2 - 1] + sorted[sorted.count / 2]) /

func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

func rollingSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(sum)
    }
    return result
}

func rollingAverage(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(Double(sum) / Double(i))
    }
    return result
}

func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    var sumOfSquares = 0
    for i in numbers {
        sum += i
        sumOfSquares += i * i
        result.append(sqrt(Double(sumOfSquares - sum * sum / Double(i)) / Double(i - 1)))
    }
    return result
}

func rollingMedian(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sortedNumbers = [Int]()
    for i in numbers {
        sortedNumbers.append(i)
        result.append(sortedNumbers.median)
    }
    return result
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 3]
func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of rolling average found until given moment
// in the sequence.
// rollingAverage(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1.0, 1.5, 2.0, 2.5, 2.6666666666666665, 2.857142857142857, 2.9285714285714285]
func rollingAverage(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    for i in numbers {
        sum += i
        result.append(Double(sum) / Double(i))
    }
    return result
}

// From a given array of integers, generate an array of rolling standard deviation found until given moment
// in the sequence.
// rollingStandardDeviation(numbers: [1, 2, 3, 2, 3, 4, 2]) == [0.0, 0.4, 0.816496580927726, 0.9486832980505138, 0.9748794418604652, 0.9869565217391304, 0.9939387755102041]
func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    var sumOfSquares = 0
    for i in numbers {
        sum += i
        sumOfSquares += i * i
        result.append(sqrt(Double(sumOfSquares - sum * sum / Double(i)) / Double(i - 1)))
    }
    return result
}

// From a given array of integers, generate an array of rolling median found until given moment
// in the sequence.
// rollingMedian(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 2, 2, 2, 3, 3]
func rollingMedian(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sortedNumbers = [Int]()
    for i in numbers {
        sortedNumbers.append(i)
        result.append(sortedNumbers.median)
    }
    return result
}

// From a given array of integers, generate an array of rolling mode found until given moment
// in the sequence.
// rollingMode(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 2, 2, 2, 

func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

func rollingSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    result.append(sum)
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

func rollingAverage(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    result.append(Double(sum) / Double(numbers.count))
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(Double(sum) / Double(i + 1))
    }
    return result
}

func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    var sumSquared = 0
    result.append(0)
    for i in 0..<numbers.count {
        sum += numbers[i]
        sumSquared += numbers[i] * numbers[i]
        result.append(sqrt(Double(sumSquared - sum * sum / Double(i + 1)) / Double(i)))
    }
    return result
}

```swift
// From a given array of integers, generate an array of rolling maximum element found until given moment
// in the sequence.
// rollingMax(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 3, 3, 3, 4, 4]
func rollingMax(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var max = numbers[0]
    result.append(max)
    for i in 1..<numbers.count {
        max = max(max, numbers[i])
        result.append(max)
    }
    return result
}

// From a given array of integers, generate an array of rolling minimum element found until given moment
// in the sequence.
// rollingMin(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 1, 1, 2, 2, 2, 2]
func rollingMin(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var min = numbers[0]
    result.append(min)
    for i in 1..<numbers.count {
        min = min(min, numbers[i])
        result.append(min)
    }
    return result
}

// From a given array of integers, generate an array of rolling sum element found until given moment
// in the sequence.
// rollingSum(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 3, 6, 8, 11, 13, 13]
func rollingSum(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var sum = 0
    result.append(sum)
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(sum)
    }
    return result
}

// From a given array of integers, generate an array of rolling average element found until given moment
// in the sequence.
// rollingAverage(numbers: [1, 2, 3, 2, 3, 4, 2]) == [1, 2, 2, 2.5, 2.5, 3, 3]
func rollingAverage(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    result.append(Double(sum) / Double(numbers.count))
    for i in 0..<numbers.count {
        sum += numbers[i]
        result.append(Double(sum) / Double(i + 1))
    }
    return result
}

// From a given array of integers, generate an array of rolling standard deviation element found until given moment
// in the sequence.
// rollingStandardDeviation(numbers: [1, 2, 3, 2, 3, 4, 2]) == [0, 0.4, 0.7071067811865476, 0.7071067811865476, 0.7071067811865476, 0.7071067811865476, 0.7071067811865476]
func rollingStandardDeviation(numbers: [Int]) -> [Double] {
    var result = [Double]()
    var sum = 0
    var sumSquared = 0
    result.append(0)
    for i in 0..<numbers.count {
        sum += numbers[i]
        sumSquared += numbers[i] * numbers[i]
        result.append(sqrt(Double(sumSquared - sum * sum / Double(i + 1)) / Double(i)))
    }
    return result
}

// From a given array of integers, generate an array of rolling variance element found until given moment
// in the sequence.
// rollingVariance(numbers: [1, 2, 3, 2, 3, 4, 2]) == [0, 0.6666666666666666, 1.3333333333333333, 1.3333333333333333, 1.3333333333333333, 1.3333333333333333, 1.3333333333333333]
func rollingVariance(numbers: [Int]) -> [Double] {
    var result = [

func makePalindrome(string: String) -> String {
    guard string.count > 1 else { return string }

    var suffix = ""
    var prefix = ""

    for i in stride(from: string.count - 1, through: 0, by: -1) {
        suffix.append(string[i])
        if isPalindrome(string: suffix) {
            break
        }
    }

    for i in 0..<string.count {
        prefix.append(string[i])
        if isPalindrome(string: prefix) {
            break
        }
    }

    return prefix + String(suffix.reversed())
}

func isPalindrome(string: String) -> Bool {
    return string == String(string.reversed())
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    guard string.count > 1 else { return string }

    var suffix = ""
    var prefix = ""

    for i in stride(from: string.count - 1, through: 0, by: -1) {
        suffix.append(string[i])
        if isPalindrome(string: suffix) {
            break
        }
    }

    for i in 0..<string.count {
        prefix.append(string[i])
        if isPalindrome(string: prefix) {
            break
        }
    }

    return prefix + String(suffix.reversed())
}

// Check if a string is a palindrome.
func isPalindrome(string: String) -> Bool {
    return string == String(string.reversed())
}

// Test the algorithm.
let input = "cat"
let output = makePalindrome(string: input)
print("Input: \(input)")
print("Output: \(output)")
assert(output == "catac")

let input2 = "cata"
let output2 = makePalindrome(string: input2)
print("Input: \(input2)")
print("Output: \(output2)")
assert(output2 == "catac")

let input3 = "a"
let output3 = makePalindrome(string: input3)
print("Input: \(input3)")
print("Output: \(output3)")
assert(output3 == "a")

let input4 = "ab"
let output4 = makePalindrome(string: input4)
print("Input: \(input4)")
print("Output: \(output4)")
assert(output4 == "ab")

let input5 = "abc"
let output5 = makePalindrome(string: input5)
print("Input: \(input5)")
print("Output: \(output5)")
assert(output5 == "abc")

let input6 = "abcd"
let output6 = makePalindrome(string: input6)
print("Input: \(input6)")
print("Output: \(output6)")
assert(output6 == "abcdabcd")

let input7 = "abcde"
let output7 = makePalindrome(string: input7)
print("Input: \(input7)")
print("Output: \(output7)")
assert(output7 == "abcdeabcde")

let input8 = "abcdef"
let output8 = makePalindrome(string: input8)
print("Input: \(input8)")
print("Output: \(output8)")
assert(output8 == "abcdefabcdef")

let input9 = "abfdef"
let output9 = makePalindrome(string: input9)
print("Input: \(input9)")
print("Output: \(output9)")
assert(output9 == "abcdefabcdefabfdef")

let input10 = "abfdefg"
let output10 = makePalindrome(string: input10)
print("Input: \(input10)")
print("Output: \(output10)")
assert(output10 == "abcdefabcdefabcdefg")

let input11 = "abfdefgz"
let output11 = makePalindrome(string: input11)
print("Input: \(input11)")
print("Output: \(output11)")
assert(output11 == "abcdefabcdefabcdefgz")

let input12 = "a"
let output12 = makePalindrome(string: input12)
print("Input: \(input12)")
print("Output: \(output12)")
assert(output12 == "a")

let input13 = "aa"
let output13 = makePalindrome(string: input13)
print("Input: \(input13)")
print("Output: \(output13)")
assert(output13 == "aa")

let input14 = "aaa"
let output14 = makePalindrome(string: input14)
print("Input: \(input14)")
print("Output: \(output14)")
assert(output14 == "aaa")

let input15 = "aab"
let output15 = makePalindrome(string: input15)
print("Input: \(input15)")
print("Output: \(output15)")
assert(output15 == "aabaa")

let input16 = "aabb"
let output16 = makePalindrome(string:

func makePalindrome(string: String) -> String {
    if string.isEmpty {
        return ""
    }
    let reversedString = String(string.characters.reverse())
    let reversedStringPrefix = longestPrefix(string: reversedString)
    return reversedStringPrefix + string + reversedStringPrefix
}

func longestPrefix(string: String) -> String {
    var prefix = ""
    for (i, char) in string.characters.enumerated() {
        if i == 0 {
            prefix += String(char)
        } else {
            if prefix.characters.last == char {
                prefix += String(char)
            } else {
                break
            }
        }
    }
    return prefix
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    if string.isEmpty {
        return ""
    }
    let reversedString = String(string.characters.reverse())
    let reversedStringPrefix = longestPrefix(string: reversedString)
    return reversedStringPrefix + string + reversedStringPrefix
}

func longestPrefix(string: String) -> String {
    var prefix = ""
    for (i, char) in string.characters.enumerated() {
        if i == 0 {
            prefix += String(char)
        } else {
            if prefix.characters.last == char {
                prefix += String(char)
            } else {
                break
            }
        }
    }
    return prefix
}

makePalindrome(string: "cat")
makePalindrome(string: "cata")
makePalindrome(string: "c")
makePalindrome(string: "ab")
makePalindrome(string: "abc")
makePalindrome(string: "aac")
makePalindrome(string: "a")
makePalindrome(string: "aa")
makePalindrome(string: "aab")
makePalindrome(string: "b")
makePalindrome(string: "ba")
makePalindrome(string: "bb")
makePalindrome(string: "bbb")
makePalindrome(string: "abcba")
makePalindrome(string: "abccab")
makePalindrome(string: "abcdabcd")
makePalindrome(string: "abcdeabcd")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz")
makePalindrome(string: "ab")
makePalindrome(string: "abcba")
makePalindrome(string: "abccab")
makePalindrome(string: "abcdabcd")
makePalindrome(string: "abcdeabcd")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz")
makePalindrome(string: "a")
makePalindrome(string: "aa")
makePalindrome(string: "aab")
makePalindrome(string: "b")
makePalindrome(string: "ba")
makePalindrome(string: "bb")
makePalindrome(string: "bbb")
makePalindrome(string: "abcba")
makePalindrome(string: "abccab")
makePalindrome(string: "abcdabcd")
makePalindrome(string: "abcdeabcd")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyza")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyza")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzab")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabc")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcd")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcde")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdef")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefg")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefgh")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefghi")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefghij")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefghijk")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefghijkl")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefghijklm")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefghijklmn")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefghijklmno")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdefghijklmnop")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabcdef

func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversedString = String(string.reversed())
    let prefix = longestPrefix(string: reversedString)
    return prefix + string + String(reversedString.suffix(prefix.count))
}

func longestPrefix(string: String) -> String {
    var i = 0
    while i < string.count / 2 {
        if string[string.index(string.startIndex, offsetBy: i)]!= string[string.index(string.startIndex, offsetBy: string.count - i - 1)] {
            return String(string.prefix(i))
        }
        i += 1
    }
    return String(string.prefix(i))
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversedString = String(string.reversed())
    let prefix = longestPrefix(string: reversedString)
    return prefix + string + String(reversedString.suffix(prefix.count))
}

func longestPrefix(string: String) -> String {
    var i = 0
    while i < string.count / 2 {
        if string[string.index(string.startIndex, offsetBy: i)]!= string[string.index(string.startIndex, offsetBy: string.count - i - 1)] {
            return String(string.prefix(i))
        }
        i += 1
    }
    return String(string.prefix(i))
}

// Test cases
assert(makePalindrome(string: "cat") == "catac")
assert(makePalindrome(string: "cata") == "catac")
assert(makePalindrome(string: "c") == "c")
assert(makePalindrome(string: "ab") == "abba")
assert(makePalindrome(string: "abc") == "abcba")
assert(makePalindrome(string: "aac") == "aacaa")
assert(makePalindrome(string: "a") == "a")
assert(makePalindrome(string: "abcd") == "abcdabcd")
assert(makePalindrome(string: "abcdcba") == "abcdcbaabcdcba")
assert(makePalindrome(string: "abcdcbaa") == "abcdcbaabcdcba")
assert(makePalindrome(string: "abcdcbaaa") == "abcdcbaabcdcbaa")
assert(makePalindrome(string: "abcdcbaaaa") == "abcdcbaabcdcbaaa")
assert(makePalindrome(string: "abcdcbaaaaa") == "abcdcbaabcdcbaaa")
assert(makePalindrome(string: "abcdcbaaaaaa") == "abcdcbaabcdcbaaaaaa")
assert(makePalindrome(string: "abcdcbaaaaaaa") == "abcdcbaabcdcbaaaaaaa")
assert(makePalindrome(string: "abcdcbaaaaaaaa") == "abcdcbaabcdcbaaaaaaaa")
assert(makePalindrome(string: "abcdcbaaaaaaaaa") == "abcdcbaabcdcbaaaaaaaaa")
assert(makePalindrome(string: "abcdcbaaaaaaaaaa") == "abcdcbaabcdcbaaaaaaaaaa")
assert(makePalindrome(string: "abcdcbaaaaaaaaaaa") == "abcdcbaabcdcbaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalindrome(string: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa") == "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
assert(makePalind

func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    
    let reversedString = String(string.reversed())
    let reversedPrefix = longestPrefix(string: reversedString)
    let palindrome = reversedString + reversedPrefix
    
    return palindrome
}

func longestPrefix(string: String) -> String {
    var i = 0
    let j = string.count - 1
    
    while i < j {
        if string[i]!= string[j] {
            break
        }
        i += 1
        j -= 1
    }
    
    return String(string[i...j])
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    
    let reversedString = String(string.reversed())
    let reversedPrefix = longestPrefix(string: reversedString)
    let palindrome = reversedString + reversedPrefix
    
    return palindrome
}

func longestPrefix(string: String) -> String {
    var i = 0
    let j = string.count - 1
    
    while i < j {
        if string[i]!= string[j] {
            break
        }
        i += 1
        j -= 1
    }
    
    return String(string[i...j])
}

makePalindrome(string: "cat")
makePalindrome(string: "cata")
makePalindrome(string: "c")
makePalindrome(string: "ab")
makePalindrome(string: "abc")
makePalindrome(string: "aac")
makePalindrome(string: "a")
makePalindrome(string: "aa")
makePalindrome(string: "aab")
makePalindrome(string: "aba")
makePalindrome(string: "abac")
makePalindrome(string: "abca")
makePalindrome(string: "aacb")
makePalindrome(string: "aacbb")
makePalindrome(string: "aacbbb")
makePalindrome(string: "aacbbbb")
makePalindrome(string: "aacbbbbb")
makePalindrome(string: "aacbbbbbb")
makePalindrome(string: "aacbbbbbbb")
makePalindrome(string: "aacbbbbbbbca")
makePalindrome(string: "aacbbbbbbbcaa")
makePalindrome(string: "aacbbbbbbbcaaa")
makePalindrome(string: "aacbbbbbbbcaaac")
makePalindrome(string: "aacbbbbbbbcaaacb")
makePalindrome(string: "aacbbbbbbbcaaacbb")
makePalindrome(string: "aacbbbbbbbcaaacbbb")
makePalindrome(string: "aacbbbbbbbcaaacbbbb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbba")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaab")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbba")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbba")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaab")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbbba")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbbbaab")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbbbaabb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbbbaabbba")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbbbaabbbaab")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbbbaabbbaabb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbbbaabbbaabbbb")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbbbaabbbaabbbbba")
makePalindrome(string: "aacbbbbbbbcaaacbbbbbbbbaabbbbbaabbbbbaabbbaabbbbba

func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    guard let (prefix, suffix) = longestPalindrome(string: string) else { return string }
    return prefix + reverse(string: suffix)
}

func longestPalindrome(string: String) -> (prefix: String, suffix: String)? {
    guard!string.isEmpty else { return nil }
    var prefix = ""
    var suffix = ""
    for i in 0..<string.count {
        let (newPrefix, newSuffix) = longestPalindrome(string: string, from: i)
        if newSuffix.count > suffix.count {
            prefix = newPrefix
            suffix = newSuffix
        }
    }
    return (prefix, suffix)
}

func longestPalindrome(string: String, from index: Int) -> (prefix: String, suffix: String) {
    var prefix = ""
    var suffix = ""
    var i = index
    var j = string.count - 1 - index
    while i >= 0 && j < string.count && string[i] == string[j] {
        prefix = String(string[i]) + prefix
        suffix = suffix + String(string[j])
        i -= 1
        j += 1
    }
    return (prefix, suffix)
}

func reverse(string: String) -> String {
    var reversed = ""
    for i in 0..<string.count {
        reversed = String(string[string.index(string.endIndex, offsetBy: -i - 1)]) + reversed
    }
    return reversed
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    guard let (prefix, suffix) = longestPalindrome(string: string) else { return string }
    return prefix + reverse(string: suffix)
}

func longestPalindrome(string: String) -> (prefix: String, suffix: String)? {
    guard!string.isEmpty else { return nil }
    var prefix = ""
    var suffix = ""
    for i in 0..<string.count {
        let (newPrefix, newSuffix) = longestPalindrome(string: string, from: i)
        if newSuffix.count > suffix.count {
            prefix = newPrefix
            suffix = newSuffix
        }
    }
    return (prefix, suffix)
}

func longestPalindrome(string: String, from index: Int) -> (prefix: String, suffix: String) {
    var prefix = ""
    var suffix = ""
    var i = index
    var j = string.count - 1 - index
    while i >= 0 && j < string.count && string[i] == string[j] {
        prefix = String(string[i]) + prefix
        suffix = suffix + String(string[j])
        i -= 1
        j += 1
    }
    return (prefix, suffix)
}

func reverse(string: String) -> String {
    var reversed = ""
    for i in 0..<string.count {
        reversed = String(string[string.index(string.endIndex, offsetBy: -i - 1)]) + reversed
    }
    return reversed
}

//: [Next](@next)

func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversedString = String(string.characters.reverse())
    let reversedStringPrefix = longestPrefix(string: reversedString)
    return reversedStringPrefix + string + reversedStringPrefix
}

func longestPrefix(string: String) -> String {
    var i = 0
    while i < string.count / 2 {
        if string[string.index(string.startIndex, offsetBy: i)]!= string[string.index(string.startIndex, offsetBy: string.count - i - 1)] {
            return String(string.characters.prefix(i))
        }
        i += 1
    }
    return String(string.characters.prefix(i))
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversedString = String(string.characters.reverse())
    let reversedStringPrefix = longestPrefix(string: reversedString)
    return reversedStringPrefix + string + reversedStringPrefix
}

func longestPrefix(string: String) -> String {
    var i = 0
    while i < string.count / 2 {
        if string[string.index(string.startIndex, offsetBy: i)]!= string[string.index(string.startIndex, offsetBy: string.count - i - 1)] {
            return String(string.characters.prefix(i))
        }
        i += 1
    }
    return String(string.characters.prefix(i))
}

makePalindrome(string: "cat")
makePalindrome(string: "cata")
makePalindrome(string: "c")
makePalindrome(string: "ab")
makePalindrome(string: "abc")
makePalindrome(string: "aac")
makePalindrome(string: "a")
makePalindrome(string: "abcd")
makePalindrome(string: "abca")
makePalindrome(string: "aacb")
makePalindrome(string: "abcba")
makePalindrome(string: "abcb")
makePalindrome(string: "ab")
makePalindrome(string: "a")
makePalindrome(string: "aa")
makePalindrome(string: "aab")
makePalindrome(string: "aba")
makePalindrome(string: "abac")
makePalindrome(string: "aac")
makePalindrome(string: "abacab")
makePalindrome(string: "abacaba")
makePalindrome(string: "aacb")
makePalindrome(string: "abcba")
makePalindrome(string: "abcb")
makePalindrome(string: "ab")
makePalindrome(string: "a")
makePalindrome(string: "aa")
makePalindrome(string: "aab")
makePalindrome(string: "aba")
makePalindrome(string: "abac")
makePalindrome(string: "aac")
makePalindrome(string: "abacab")
makePalindrome(string: "abacaba")
makePalindrome(string: "aacb")
makePalindrome(string: "abcba")
makePalindrome(string: "abcb")
makePalindrome(string: "ab")
makePalindrome(string: "a")
makePalindrome(string: "aa")
makePalindrome(string: "aab")
makePalindrome(string: "aba")
makePalindrome(string: "abac")
makePalindrome(string: "aac")
makePalindrome(string: "abacab")
makePalindrome(string: "abacaba")
makePalindrome(string: "aacb")
makePalindrome(string: "abcba")
makePalindrome(string: "abcb")
makePalindrome(string: "ab")
makePalindrome(string: "a")
makePalindrome(string: "aa")
makePalindrome(string: "aab")
makePalindrome(string: "aba")
makePalindrome(string: "abac")
makePalindrome(string: "aac")
makePalindrome(string: "abacab")
makePalindrome(string: "abacaba")
makePalindrome(string: "aacb")
makePalindrome(string: "abcba")
makePalindrome(string: "abcb")
makePalindrome(string: "ab")
makePalindrome(string: "a")
makePalindrome(string: "aa")
makePalindrome(string: "aab")
makePalindrome(string: "aba")
makePalindrome(string: "abac")
makePalindrome(string: "aac")
makePalindrome(string: "abacab")
makePalindrome(string: "abacaba")
makePalindrome(string: "aacb")
makePalindrome(string: "abcba")
makePalindrome(string: "abcb")
makePalindrome(string: "ab")
makePalindrome(string

func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversed = String(string.reversed())
    var prefix = ""
    var suffix = ""
    for (i, char) in string.enumerated() {
        if reversed[i] == char {
            prefix.append(char)
        } else {
            suffix = String(reversed[i...]) + suffix
            break
        }
    }
    return prefix + string + suffix
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversed = String(string.reversed())
    var prefix = ""
    var suffix = ""
    for (i, char) in string.enumerated() {
        if reversed[i] == char {
            prefix.append(char)
        } else {
            suffix = String(reversed[i...]) + suffix
            break
        }
    }
    return prefix + string + suffix
}

// Tests
assert(makePalindrome(string: "cat") == "catac")
assert(makePalindrome(string: "cata") == "catac")
assert(makePalindrome(string: "c") == "c")
assert(makePalindrome(string: "ab") == "abba")
assert(makePalindrome(string: "abc") == "abcba")
assert(makePalindrome(string: "abcd") == "abcdabcd")
assert(makePalindrome(string: "abcde") == "abcdeabcde")
assert(makePalindrome(string: "abcdef") == "abcdefabcdef")
assert(makePalindrome(string: "abcdefg") == "abcdefgabcdefg")
assert(makePalindrome(string: "abcdefgh") == "abcdefghabcdefgh")
assert(makePalindrome(string: "abcdefghi") == "abcdefghiabcdefghi")
assert(makePalindrome(string: "abcdefghij") == "abcdefghijabcdefghij")
assert(makePalindrome(string: "abcdefghijkl") == "abcdefghijklabcdefghijkl")
assert(makePalindrome(string: "abcdefghijklmn") == "abcdefghijklmnabcdefghijklmn")
assert(makePalindrome(string: "abcdefghijklmno") == "abcdefghijklmnoabcdefghijklmno")
assert(makePalindrome(string: "abcdefghijklmnop") == "abcdefghijklmnopabcdefghijklmnop")
assert(makePalindrome(string: "abcdefghijklmnopq") == "abcdefghijklmnopqabcdefghijklmnopq")
assert(makePalindrome(string: "abcdefghijklmnopqr") == "abcdefghijklmnopqrabcdefghijklmnopqr")
assert(makePalindrome(string: "abcdefghijklmnopqrs") == "abcdefghijklmnopqrsabcdefghijklmnopqrs")
assert(makePalindrome(string: "abcdefghijklmnopqrst") == "abcdefghijklmnopqrstabcdefghijklmnopqrst")
assert(makePalindrome(string: "abcdefghijklmnopqrstu") == "abcdefghijklmnopqrstuabcdefghijklmnopqrstu")
assert(makePalindrome(string: "abcdefghijklmnopqrstuv") == "abcdefghijklmnopqrstuvabcdefghijklmnopqrstuv")
assert(makePalindrome(string: "abcdefghijklmnopqrstuvw") == "abcdefghijklmnopqrstuvwabcdefghijklmnopqrstuvw")
assert(makePalindrome(string: "abcdefghijklmnopqrstuvwx") == "abcdefghijklmnopqrstuvwxabcdefghijklmnopqrstuvwx")
assert(makePalindrome(string: "abcdefghijklmnopqrstuvwxy") == "abcdefghijklmnopqrstuvwxyabcdefghijklmnopqrstuvwxy")
assert(makePalindrome(string: "abcdefghijklmnopqrstuvwxyz") == "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz")
assert(makePalindrome(string: "abcdefghijklmnopqrstuvwxyza") == "abcdefghijklmnopqrstuvwxyzaabcdefghijklmnopqrstuvwxyza")
assert(makePalindrome(string: "abcdefghijklmnopqrstuvwxyzab") == "abcdefghijklmnopqrstuvwxyzababcdefghijklmnopqrstuvwxyzab")
assert(makePalindrome(string: "abcdefghijklmnopqrstuvwxyzabc") == "abcdefghijklmnopqrstuvwxyzabcabcdefgh

func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversedString = String(string.reversed())
    let reversedStringWithPrefix = reversedString + string
    let palindrome = findLongestPrefix(string: reversedStringWithPrefix)
    return palindrome + string
}

func findLongestPrefix(string: String) -> String {
    var left = 0
    var right = string.count - 1
    while left < right {
        if string[left]!= string[right] {
            return String(string[left...right])
        }
        left += 1
        right -= 1
    }
    return String(string[left...right])
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversedString = String(string.reversed())
    let reversedStringWithPrefix = reversedString + string
    let palindrome = findLongestPrefix(string: reversedStringWithPrefix)
    return palindrome + string
}

func findLongestPrefix(string: String) -> String {
    var left = 0
    var right = string.count - 1
    while left < right {
        if string[left]!= string[right] {
            return String(string[left...right])
        }
        left += 1
        right -= 1
    }
    return String(string[left...right])
}

makePalindrome(string: "cat")
makePalindrome(string: "cata")
makePalindrome(string: "c")
makePalindrome(string: "ab")
makePalindrome(string: "abc")
makePalindrome(string: "aac")
makePalindrome(string: "a")
makePalindrome(string: "aa")
makePalindrome(string: "aab")
makePalindrome(string: "b")
makePalindrome(string: "bb")
makePalindrome(string: "bbb")
makePalindrome(string: "bbbb")
makePalindrome(string: "cbbd")
makePalindrome(string: "abcd")
makePalindrome(string: "abcde")
makePalindrome(string: "abcdef")
makePalindrome(string: "abcdefg")
makePalindrome(string: "abcdefgh")
makePalindrome(string: "abcdefghi")
makePalindrome(string: "abcdefghij")
makePalindrome(string: "abcdefghijk")
makePalindrome(string: "abcdefghijkl")
makePalindrome(string: "abcdefghijklmn")
makePalindrome(string: "abcdefghijklmno")
makePalindrome(string: "abcdefghijklmnop")
makePalindrome(string: "abcdefghijklmnopq")
makePalindrome(string: "abcdefghijklmnopqr")
makePalindrome(string: "abcdefghijklmnopqrs")
makePalindrome(string: "abcdefghijklmnopqrst")
makePalindrome(string: "abcdefghijklmnopqrstu")
makePalindrome(string: "abcdefghijklmnopqrstuv")
makePalindrome(string: "abcdefghijklmnopqrstuvw")
makePalindrome(string: "abcdefghijklmnopqrstuvwx")
makePalindrome(string: "abcdefghijklmnopqrstuvwxy")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz01")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz012")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz01234")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz012345")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123456")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz01234567")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz012345678")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123456789")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123456789a")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123456789ab")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123456789abc")
makePalindrome(string: "

func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversed = String(string.reversed())
    let prefix = longestPrefix(string: reversed)
    return prefix + string + String(reversed[prefix.count..<reversed.count])
}

func longestPrefix(string: String) -> String {
    var i = 0
    while i < string.count / 2 {
        if string[string.index(string.startIndex, offsetBy: i)]!= string[string.index(string.startIndex, offsetBy: string.count - i - 1)] {
            return String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: string.count - i - 1)])
        }
        i += 1
    }
    return String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: string.count - i - 1)])
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    guard!string.isEmpty else { return "" }
    let reversed = String(string.reversed())
    let prefix = longestPrefix(string: reversed)
    return prefix + string + String(reversed[prefix.count..<reversed.count])
}

func longestPrefix(string: String) -> String {
    var i = 0
    while i < string.count / 2 {
        if string[string.index(string.startIndex, offsetBy: i)]!= string[string.index(string.startIndex, offsetBy: string.count - i - 1)] {
            return String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: string.count - i - 1)])
        }
        i += 1
    }
    return String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: string.count - i - 1)])
}

makePalindrome(string: "cat") // "catac"
makePalindrome(string: "cata") // "catac"
makePalindrome(string: "c") // "c"
makePalindrome(string: "ab") // "ab"
makePalindrome(string: "abc") // "abc"
makePalindrome(string: "abcd") // "abcd"
makePalindrome(string: "abcde") // "abcde"
makePalindrome(string: "abcdef") // "abcdef"
makePalindrome(string: "abcdefg") // "abcdefg"
makePalindrome(string: "abacdfgdcaba") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaa") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaa") // "abacdfgdcabaa"
makePalindrome(string: "abacdfgdcabaab") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaabb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaabbb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaabbba") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaabbab") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaabbabb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaabbbb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaabbbbb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaab") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaabb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaabbb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaabbba") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaabbab") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaabbabb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaabbbb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaabbbbb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaaab") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaaabb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaaabbb") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaaabbba") // "abacdfgdcaba"
makePalindrome(string: "abacdfgdcabaaaabbab") // "abacdfgdcaba

func makePalindrome(string: String) -> String {
    guard string.count > 1 else { return string }
    
    let reversedString = String(string.reversed())
    var longestPrefix = ""
    var longestSuffix = ""
    
    for (index, char) in string.enumerated() {
        let reversedIndex = reversedString.index(reversedString.startIndex, offsetBy: index)
        let currentPrefix = String(string[string.index(string.startIndex, offsetBy: index)...])
        let currentSuffix = String(reversedString[reversedIndex...])
        
        if currentPrefix == currentSuffix {
            longestPrefix = currentPrefix
            longestSuffix = currentSuffix
            break
        }
    }
    
    return longestPrefix + string + longestSuffix
}

```swift
// Find the shortest palindrome that begins with a supplied string.
// Algorithm idea is simple:
// - Find the longest postfix of supplied string that is a palindrome.
// - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
// makePalindrome(string: "") == ""
// makePalindrome(string: "cat") == "catac"
// makePalindrome(string: "cata") == "catac"
func makePalindrome(string: String) -> String {
    guard string.count > 1 else { return string }
    
    let reversedString = String(string.reversed())
    var longestPrefix = ""
    var longestSuffix = ""
    
    for (index, char) in string.enumerated() {
        let reversedIndex = reversedString.index(reversedString.startIndex, offsetBy: index)
        let currentPrefix = String(string[string.index(string.startIndex, offsetBy: index)...])
        let currentSuffix = String(reversedString[reversedIndex...])
        
        if currentPrefix == currentSuffix {
            longestPrefix = currentPrefix
            longestSuffix = currentSuffix
            break
        }
    }
    
    return longestPrefix + string + longestSuffix
}

makePalindrome(string: "cat")
makePalindrome(string: "cata")
makePalindrome(string: "c")
makePalindrome(string: "ab")
makePalindrome(string: "abc")
makePalindrome(string: "abcd")
makePalindrome(string: "abcde")
makePalindrome(string: "abcdef")
makePalindrome(string: "abcdefg")
makePalindrome(string: "abcdefgh")
makePalindrome(string: "abcdefghi")
makePalindrome(string: "abcdefghij")
makePalindrome(string: "abcdefghijk")
makePalindrome(string: "abcdefghijkl")
makePalindrome(string: "abcdefghijklm")
makePalindrome(string: "abcdefghijklmn")
makePalindrome(string: "abcdefghijklmno")
makePalindrome(string: "abcdefghijklmnop")
makePalindrome(string: "abcdefghijklmnopq")
makePalindrome(string: "abcdefghijklmnopqr")
makePalindrome(string: "abcdefghijklmnopqrs")
makePalindrome(string: "abcdefghijklmnopqrst")
makePalindrome(string: "abcdefghijklmnopqrstu")
makePalindrome(string: "abcdefghijklmnopqrstuv")
makePalindrome(string: "abcdefghijklmnopqrstuvw")
makePalindrome(string: "abcdefghijklmnopqrstuvwx")
makePalindrome(string: "abcdefghijklmnopqrstuvwxy")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz01")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz012")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz01234")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz012345")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123456")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz01234567")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz012345678")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123456789")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz01234567890")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz012345678901")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz0123456789012")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz01234567890123")
makePalindrome(string: "abcdefghijklmnopqrstuvwxyz012345678901234")
makePalindrome(string: "abcdef

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(characterA.asciiValue! ^ characterB.asciiValue!))
    }
    return result
}

func xor(a: Int, b: Int) -> Int {
    return a ^ b
}

func xor(a: Double, b: Double) -> Double {
    return Double(Int(a) ^ Int(b))
}

func xor(a: Float, b: Float) -> Float {
    return Float(Int(a) ^ Int(b))
}

func xor(a: UInt, b: UInt) -> UInt {
    return a ^ b
}

func xor(a: UInt8, b: UInt8) -> UInt8 {
    return UInt8(Int(a) ^ Int(b))
}

func xor(a: UInt16, b: UInt16) -> UInt16 {
    return UInt16(Int(a) ^ Int(b))
}

func xor(a: UInt32, b: UInt32) -> UInt32 {
    return a ^ b
}

func xor(a: UInt64, b: UInt64) -> UInt64 {
    return a ^ b
}

func xor(a: Int8, b: Int8) -> Int8 {
    return Int8(Int(a) ^ Int(b))
}

func xor(a: Int16, b: Int16) -> Int16 {
    return Int16(Int(a) ^ Int(b))
}

func xor(a: Int32, b: Int32) -> Int32 {
    return Int32(Int(a) ^ Int(b))
}

func xor(a: Int64, b: Int64) -> Int64 {
    return a ^ b
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(characterA.asciiValue! ^ characterB.asciiValue!))
    }
    return result
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: Int, b: Int) -> Int {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: Double, b: Double) -> Double {
    return Double(Int(a) ^ Int(b))
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: Float, b: Float) -> Float {
    return Float(Int(a) ^ Int(b))
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: UInt, b: UInt) -> UInt {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: UInt8, b: UInt8) -> UInt8 {
    return UInt8(Int(a) ^ Int(b))
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: UInt16, b: UInt16) -> UInt16 {
    return UInt16(Int(a) ^ Int(b))
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: UInt32, b: UInt32) -> UInt32 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: UInt64, b: UInt64) -> UInt64 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: Int8, b: Int8) -> Int8 {
    return Int8(Int(a) ^ Int(b))
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: Int16, b: Int16) -> Int16 {
    return Int16(Int(a) ^ Int(b))
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: Int32, b: Int32) -> Int32 {
    return Int32(Int(a) ^ Int(b))
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: Int64, b: Int64) -> Int64 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary X

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! ^ charB.asciiValue!))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (charA, charB) in zip(a, b) {
        result = result << 1
        result = result | (charA.asciiValue! ^ charB.asciiValue!)
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

func stringXor(a: String, b: String) -> Int {
    return (Int(a, radix: 2) &+ Int(b, radix: 2)) &+ (Int(a, radix: 2) &* Int(b, radix: 2))
}

func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ⊻ Int(b, radix: 2)
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! ^ charB.asciiValue!))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (charA, charB) in zip(a, b) {
        result = result << 1
        result = result | (charA.asciiValue! ^ charB.asciiValue!)
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return (Int(a, radix: 2) &+ Int(b, radix: 2)) &+ (Int(a, radix: 2) &* Int(b, radix: 2))
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ⊻ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return (Int(a, radix: 2) &+ Int(b, radix: 2)) &+ (Int(a, radix: 2) &* Int(b, radix: 2))
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ⊻ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! ^ charB.asciiValue!))
    }
    return result
}

func stringAnd(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! & charB.asciiValue!))
    }
    return result
}

func stringOr(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! | charB.asciiValue!))
    }
    return result
}

func stringNot(a: String) -> String {
    var result = ""
    for char in a {
        result.append(String(char.asciiValue! ^ 1))
    }
    return result
}

func stringRightShift(a: String, b: Int) -> String {
    var result = ""
    for char in a {
        result.append(String(char.asciiValue! >> b))
    }
    return result
}

func stringLeftShift(a: String, b: Int) -> String {
    var result = ""
    for char in a {
        result.append(String(char.asciiValue! << b))
    }
    return result
}

func stringAddition(a: String, b: String) -> String {
    var result = ""
    var overflow = 0
    for (charA, charB) in zip(a, b) {
        let sum = charA.asciiValue! + charB.asciiValue! + overflow
        result.append(String(sum % 2))
        overflow = sum / 2
    }
    if overflow > 0 {
        result.append(String(overflow))
    }
    return result
}

func stringSubtraction(a: String, b: String) -> String {
    var result = ""
    var overflow = 0
    for (charA, charB) in zip(a, b) {
        let difference = charA.asciiValue! - charB.asciiValue! - overflow
        result.append(String(difference % 2))
        overflow = difference / 2
    }
    return result
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! ^ charB.asciiValue!))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary AND (&) on these inputs and return result also as a string.
// stringAnd(a: "010", b: "110") == "010"
func stringAnd(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! & charB.asciiValue!))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary OR (|) on these inputs and return result also as a string.
// stringOr(a: "010", b: "110") == "110"
func stringOr(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! | charB.asciiValue!))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary NOT (!) on these inputs and return result also as a string.
// stringNot(a: "010") == "101"
func stringNot(a: String) -> String {
    var result = ""
    for char in a {
        result.append(String(char.asciiValue! ^ 1))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform right shift (>>) on these inputs and return result also as a string.
// stringRightShift(a: "010", b: 1) == "001"
func stringRightShift(a: String, b: Int) -> String {
    var result = ""
    for char in a {
        result.append(String(char.asciiValue! >> b))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform left shift (<<) on these inputs and return result also as a string.
// stringLeftShift(a: "010", b: 1) == "100"
func stringLeftShift(a: String, b: Int) -> String {
    var result = ""
    for char in a {
        result.append(String(char.asciiValue! << b))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform addition (+) on these inputs and return result also as a string.
// stringAddition(a: "010", b: "110") == "1000"
func stringAddition(a: String, b: String) -> String {
    var result = ""
    var overflow = 0
    for (charA, charB) in zip(a, b) {
        let sum = charA.asciiValue! + charB.asciiValue! + overflow
        result.append(String(sum % 2))
        overflow = sum / 2
    }
    if overflow > 0 {
        result.append(String(overflow))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform subtraction (-) on these inputs and return result also as a string.
// stringSubtraction(a: "010", b: "110") == "100"
func stringSubtraction(a: String, b: String) -> String {
    var result = ""
    var overflow = 0
    for (charA, charB) in zip(a, b) {
        let difference = charA.asciiValue! - charB.asciiValue! - overflow
        result.append(String(difference % 2))
        overflow = difference / 2
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform multiplication (*) on these inputs and return result also as a string.
// stringMultiplication(a:

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! ^ charB.asciiValue!))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (charA, charB) in zip(a, b) {
        result = result << 1
        result = result | (charA.asciiValue! ^ charB.asciiValue!)
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

func stringXor(a: String, b: String) -> Int {
    return (Int(a, radix: 2) &+ Int(b, radix: 2)) &+ (Int(a, radix: 2) &* Int(b, radix: 2))
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (charA, charB) in zip(a, b) {
        result.append(String(charA.asciiValue! ^ charB.asciiValue!))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (charA, charB) in zip(a, b) {
        result = result << 1
        result = result | (charA.asciiValue! ^ charB.asciiValue!)
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return (Int(a, radix: 2) &+ Int(b, radix: 2)) &+ (Int(a, radix: 2) &* Int(b, radix: 2))
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return (Int(a, radix: 2) &+ Int(b, radix: 2)) &+ (Int(a, radix: 2) &* Int(b, radix: 2))
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return (Int(a, radix: 2) &+ Int(b, radix: 2)) &+ (Int(a, radix: 2) &* Int(b, radix: 2))
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return (Int(a, radix: 2) &+ Int(b, radix: 2)) &+ (Int(a, radix: 2) &* Int(b, radix: 2))
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return (Int(a, radix: 2) &+ Int(b, radix: 2)) &+ (Int(a, radix: 2) &* Int(b, radix: 2))
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String,

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(bitPattern: characterA.asciiValue! ^ characterB.asciiValue!))
    }
    return result
}

func stringAnd(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(bitPattern: characterA.asciiValue! & characterB.asciiValue!))
    }
    return result
}

func stringOr(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(bitPattern: characterA.asciiValue! | characterB.asciiValue!))
    }
    return result
}

func stringNot(a: String) -> String {
    var result = ""
    for character in a {
        result.append(String(bitPattern: ~character.asciiValue!))
    }
    return result
}

func stringRightShift(a: String, b: Int) -> String {
    var result = ""
    for character in a {
        result.append(String(bitPattern: character.asciiValue! >> b))
    }
    return result
}

func stringLeftShift(a: String, b: Int) -> String {
    var result = ""
    for character in a {
        result.append(String(bitPattern: character.asciiValue! << b))
    }
    return result
}

func stringAddition(a: String, b: String) -> String {
    var result = ""
    var overflow = 0
    for (characterA, characterB) in zip(a, b) {
        let characterAValue = characterA.asciiValue!
        let characterBValue = characterB.asciiValue!
        let characterSum = characterAValue + characterBValue + overflow
        overflow = characterSum >> 8
        result.append(String(bitPattern: characterSum & 0xFF))
    }
    if overflow!= 0 {
        result.append(String(bitPattern: overflow))
    }
    return result
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(bitPattern: characterA.asciiValue! ^ characterB.asciiValue!))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary AND on these inputs and return result also as a string.
// stringAnd(a: "010", b: "110") == "010"
func stringAnd(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(bitPattern: characterA.asciiValue! & characterB.asciiValue!))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary OR on these inputs and return result also as a string.
// stringOr(a: "010", b: "110") == "110"
func stringOr(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(bitPattern: characterA.asciiValue! | characterB.asciiValue!))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary NOT on these inputs and return result also as a string.
// stringNot(a: "010") == "101"
func stringNot(a: String) -> String {
    var result = ""
    for character in a {
        result.append(String(bitPattern: ~character.asciiValue!))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform right shift on string a by b positions and return result as a string.
// stringRightShift(a: "010", b: 1) == "001"
func stringRightShift(a: String, b: Int) -> String {
    var result = ""
    for character in a {
        result.append(String(bitPattern: character.asciiValue! >> b))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform left shift on string a by b positions and return result as a string.
// stringLeftShift(a: "010", b: 1) == "100"
func stringLeftShift(a: String, b: Int) -> String {
    var result = ""
    for character in a {
        result.append(String(bitPattern: character.asciiValue! << b))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform addition on string a and b and return result as a string.
// stringAddition(a: "010", b: "110") == "1000"
func stringAddition(a: String, b: String) -> String {
    var result = ""
    var overflow = 0
    for (characterA, characterB) in zip(a, b) {
        let characterAValue = characterA.asciiValue!
        let characterBValue = characterB.asciiValue!
        let characterSum = characterAValue + characterBValue + overflow
        overflow = characterSum >> 8
        result.append(String(bitPattern: characterSum & 0xFF))
    }
    if overflow!= 0 {
        result.append(String(bitPattern: overflow))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform subtraction on string a and b and return result as a string.
// stringSubtraction(a: "010", b: "110") == "000"
func stringSubtraction(a: String, b: String) -> String {
    var result = ""
    var overflow = 0
    for (characterA, characterB) in zip(a, b) {
        let characterAValue = characterA.asciiValue!
        let characterBValue = characterB.asciiValue!
        let characterDifference = characterAValue - characterBValue - overflow
        overflow = (characterDifference >> 7) & 1
        result.append(String(bit

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) ^ Int(characterB)))
    }
    return result
}

func xor(a: Int, b: Int) -> Int {
    return a ^ b
}

func xor(a: Double, b: Double) -> Double {
    return Double(Int(a) ^ Int(b))
}

func xor(a: Float, b: Float) -> Float {
    return Float(Int(a) ^ Int(b))
}

func xor(a: UInt, b: UInt) -> UInt {
    return a ^ b
}

func xor(a: Bool, b: Bool) -> Bool {
    return a!= b
}

func xor(a: Int8, b: Int8) -> Int8 {
    return a ^ b
}

func xor(a: Int16, b: Int16) -> Int16 {
    return a ^ b
}

func xor(a: Int32, b: Int32) -> Int32 {
    return a ^ b
}

func xor(a: Int64, b: Int64) -> Int64 {
    return a ^ b
}

func xor(a: UInt8, b: UInt8) -> UInt8 {
    return a ^ b
}

func xor(a: UInt16, b: UInt16) -> UInt16 {
    return a ^ b
}

func xor(a: UInt32, b: UInt32) -> UInt32 {
    return a ^ b
}

func xor(a: UInt64, b: UInt64) -> UInt64 {
    return a ^ b
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) ^ Int(characterB)))
    }
    return result
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: Int, b: Int) -> Int {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: Double, b: Double) -> Double {
    return Double(Int(a) ^ Int(b))
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10.5, b: 20.5) == 30.0
func xor(a: Float, b: Float) -> Float {
    return Float(Int(a) ^ Int(b))
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: UInt, b: UInt) -> UInt {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: Bool, b: Bool) -> Bool {
    return a!= b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: Int8, b: Int8) -> Int8 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: Int16, b: Int16) -> Int16 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: Int32, b: Int32) -> Int32 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: Int64, b: Int64) -> Int64 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: UInt8, b: UInt8) -> UInt8 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: UInt16, b: UInt16) -> UInt16 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: UInt32, b: UInt32) -> UInt32 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a: UInt64, b: UInt64) -> UInt64 {
    return a ^ b
}

// Input are two numbers a and b.
// Perform binary XOR on these inputs and return result.
// xor(a: 10, b: 20) == 30
func xor(a

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) ^ Int(characterB)))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (characterA, characterB) in zip(a, b) {
        result = result << 1
        result = result | (Int(characterA) ^ Int(characterB))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) ^ Int(characterB)))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (characterA, characterB) in zip(a, b) {
        result = result << 1
        result = result | (Int(characterA) ^ Int(characterB))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

//

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) ^ Int(characterB)))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (characterA, characterB) in zip(a, b) {
        result = result << 1
        result = result | (Int(characterA) ^ Int(characterB))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, characterA) in a.enumerated() {
        result = result << 1
        result = result | (Int(characterA) ^ Int(b[index]))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, _) in a.enumerated() {
        result = result << 1
        result = result | (Int(a[index]) ^ Int(b[index]))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    var result = 0
    for characterA in a {
        result = result << 1
        result = result | (Int(characterA) ^ Int(b[result & 1]))
    }
    return result
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) ^ Int(characterB)))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (characterA, characterB) in zip(a, b) {
        result = result << 1
        result = result | (Int(characterA) ^ Int(characterB))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, characterA) in a.enumerated() {
        result = result << 1
        result = result | (Int(characterA) ^ Int(b[index]))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, _) in a.enumerated() {
        result = result << 1
        result = result | (Int(a[index]) ^ Int(b[index]))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for characterA in a {
        result = result << 1
        result = result | (Int(characterA) ^ Int(b[result & 1]))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, characterA) in a.enumerated() {
        result = result << 1
        result = result | (Int(characterA) ^ Int(b[index]))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, characterA) in a.enumerated() {
        result = result << 1
        result = result | (Int(characterA) ^ Int(b[index]))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, characterA) in a.enumerated() {
        result = result << 1
        result = result | (Int(characterA) ^ Int(b[index]))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010",

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) ^ Int(characterB)))
    }
    return result
}

func stringAnd(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) & Int(characterB)))
    }
    return result
}

func stringOr(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) | Int(characterB)))
    }
    return result
}

func stringLeftShift(a: String, b: Int) -> String {
    var result = a
    for _ in 0..<b {
        result.insert(result.first!, at: result.startIndex)
    }
    return result
}

func stringRightShift(a: String, b: Int) -> String {
    var result = a
    for _ in 0..<b {
        result.removeFirst()
    }
    return result
}

func stringNot(a: String) -> String {
    var result = ""
    for character in a {
        result.append(String(1 - Int(character)))
    }
    return result
}

func stringOneComplement(a: String) -> String {
    return stringNot(a: stringAnd(a: a, b: "11111111"))
}

func stringTwoComplement(a: String) -> String {
    return stringOneComplement(a: stringNot(a: a)) + "0"
}

func stringAddition(a: String, b: String) -> String {
    var result = ""
    var overflow = 0
    for (characterA, characterB) in zip(a.reversed(), b.reversed()) {
        let addition = Int(characterA) + Int(characterB) + overflow
        result.insert(String(addition % 2), at: result.startIndex)
        overflow = addition / 2
    }
    if overflow > 0 {
        result.insert(String(overflow), at: result.startIndex)
    }
    return result.reversed()
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) ^ Int(characterB)))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary AND on these inputs and return result also as a string.
// stringAnd(a: "010", b: "110") == "010"
func stringAnd(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) & Int(characterB)))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary OR on these inputs and return result also as a string.
// stringOr(a: "010", b: "110") == "110"
func stringOr(a: String, b: String) -> String {
    var result = ""
    for (characterA, characterB) in zip(a, b) {
        result.append(String(Int(characterA) | Int(characterB)))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary Left Shift on these inputs and return result also as a string.
// stringLeftShift(a: "010", b: 2) == "00010"
func stringLeftShift(a: String, b: Int) -> String {
    var result = a
    for _ in 0..<b {
        result.insert(result.first!, at: result.startIndex)
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary Right Shift on these inputs and return result also as a string.
// stringRightShift(a: "010", b: 2) == "10"
func stringRightShift(a: String, b: Int) -> String {
    var result = a
    for _ in 0..<b {
        result.removeFirst()
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary NOT on these inputs and return result also as a string.
// stringNot(a: "010") == "101"
func stringNot(a: String) -> String {
    var result = ""
    for character in a {
        result.append(String(1 - Int(character)))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary One's Complement on these inputs and return result also as a string.
// stringOneComplement(a: "010") == "101"
func stringOneComplement(a: String) -> String {
    return stringNot(a: stringAnd(a: a, b: "11111111"))
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary Two's Complement on these inputs and return result also as a string.
// stringTwoComplement(a: "010") == "101"
func stringTwoComplement(a: String) -> String {
    return stringOneComplement(a: stringNot(a: a)) + "0"
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform addition on these inputs and return result also as a string.
// stringAddition(a: "101", b: "101") == "1100"
func stringAddition(a: String, b: String) -> String {
    var result = ""
    var overflow = 0
    for (characterA, characterB) in zip(a.reversed(), b.reversed()) {
        let addition = Int(characterA) + Int(characterB) + overflow
        result.insert(String(addition % 2), at: result.startIndex)
        overflow = addition / 2
    }
    if overflow > 0 {
        result.insert(String(overflow), at: result.startIndex)
    }
    return result.reversed()
}

// Input

func stringXor(a: String, b: String) -> String {
    var result = ""
    for (index, character) in a.enumerated() {
        result.append(String(Int(character) ^ Int(b[index])))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, character) in a.enumerated() {
        result = result | (Int(character) ^ Int(b[index]))
    }
    return result
}

func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, character) in zip(a, b) {
        result = result | (Int(character) ^ Int(index))
    }
    return result
}

```swift
// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result also as a string.
// stringXor(a: "010", b: "110") == "100"
func stringXor(a: String, b: String) -> String {
    var result = ""
    for (index, character) in a.enumerated() {
        result.append(String(Int(character) ^ Int(b[index])))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, character) in a.enumerated() {
        result = result | (Int(character) ^ Int(b[index]))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    return Int(a, radix: 2) ^ Int(b, radix: 2)
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, character) in a.enumerated() {
        result = result | (Int(character) ^ Int(b[index]))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, character) in zip(a, b) {
        result = result | (Int(character) ^ Int(index))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, character) in zip(a, b) {
        result = result | (Int(character) ^ Int(index))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, character) in zip(a, b) {
        result = result | (Int(character) ^ Int(index))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these inputs and return result as an integer.
// stringXor(a: "010", b: "110") == 100
func stringXor(a: String, b: String) -> Int {
    var result = 0
    for (index, character) in zip(a, b) {
        result = result | (Int(character) ^ Int(index))
    }
    return result
}

// Input are two strings a and b consisting only of 1s and 0s.
// Perform binary XOR on these

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var smallest = numbers[0]
    
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    
    return smallest
}

func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var largest = numbers[0]
    
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    
    return largest
}

func sum(numbers: [Int]) -> Int {
    var sum = 0
    
    for number in numbers {
        sum += number
    }
    
    return sum
}

func average(numbers: [Int]) -> Int {
    return sum(numbers: numbers) / numbers.count
}

func median(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    let sortedNumbers = numbers.sorted()
    let middleIndex = sortedNumbers.count / 2
    
    if sortedNumbers.count % 2 == 0 {
        return (sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2
    } else {
        return sortedNumbers[middleIndex]
    }
}

func positiveCount(numbers: [Int]) -> Int {
    var count = 0
    
    for number in numbers {
        if number > 0 {
            count += 1
        }
    }
    
    return count
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of integers, return the smallest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// smallest(numbers: [] as [Int]) == nil
// smallest(numbers: [1, 2, 3]) == 1
// smallest(numbers: [1, 2, 3, 1]) == 1
func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var smallest = numbers[0]
    
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    
    return smallest
}

// Out of array of integers, return the largest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// largest(numbers: [] as [Int]) == nil
// largest(numbers: [1, 2, 3]) == 3
// largest(numbers: [1, 2, 3, 1]) == 1
func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var largest = numbers[0]
    
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    
    return largest
}

// Out of array of integers, return the sum of all values. Return 0 in case the input array is empty.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3]) == 6
// sum(numbers: [1, 2, 3, 1]) == 7
func sum(numbers: [Int]) -> Int {
    var sum = 0
    
    for number in numbers {
        sum += number
    }
    
    return sum
}

// Out of array of integers, return the average of all values. Return 0 in case the input array is empty.
// average(numbers: [] as [Int]) == 0
// average(numbers: [1, 2, 3]) == 2
// average(numbers: [1, 2, 3, 1]) == 2
func average(numbers: [Int]) -> Int {
    return sum(numbers: numbers) / numbers.count
}

// Out of array of integers, return the median value. Return nil in case the input array is empty.
// median(numbers: [] as [Int]) == nil
// median(numbers: [1, 2, 3]) == 2
// median(numbers: [1, 2, 3, 1]) == 2
// median(numbers: [1, 2, 3, 4]) == 2.5
func median(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    let sortedNumbers = numbers.sorted()
    let middleIndex = sortedNumbers.count / 2
    
    if sortedNumbers.count % 2 == 0 {
        return (sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2
    } else {
        return sortedNumbers[middleIndex]
    }
}

// Out of array of integers, return the count of all positive values. Return 0 in case the input array is empty.
// positiveCount(numbers: [] as [Int]) == 0
// positiveCount(numbers: [1, 2, 3]) == 3
// positiveCount(numbers: [1, 2, 3, -1]) == 3
// positiveCount(numbers: [1, 2, 3, -1, 0]) == 3
func positiveCount(numbers: [Int]) -> Int {
    var count = 0
    
    for number in numbers {
        if number > 0 {
            count += 1
        }
    }
    
    return count
}

// Out of array of integers, return the count of all negative values. Return 0 in case the input array is empty.
// negativeCount(numbers: [] as [Int]) == 0
// negativeCount(numbers: [1, 2, 3]) == 0
// negativeCount(numbers: [1, 2, 3, -1]) == 1
// negativeCount(numbers: [1, 2, 3, -1,

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    return smallest
}

func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    return largest
}

func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

func count(numbers: [Int]) -> Int {
    return numbers.count
}

func average(numbers: [Int]) -> Double {
    return Double(sum(numbers: numbers)) / Double(count(numbers: numbers))
}

func median(numbers: [Int]) -> Double? {
    if numbers.isEmpty {
        return nil
    }
    let sortedNumbers = numbers.sorted()
    let count = sortedNumbers.count
    if count % 2 == 0 {
        let middleIndex = count / 2
        return Double(sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2
    } else {
        let middleIndex = count / 2
        return Double(sortedNumbers[middleIndex])
    }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of integers, return the smallest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// smallest(numbers: [] as [Int]) == nil
// smallest(numbers: [1, 2, 3]) == 1
// smallest(numbers: [1, 2, 3, 1]) == 1
func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    return smallest
}

// Out of array of integers, return the largest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// largest(numbers: [] as [Int]) == nil
// largest(numbers: [1, 2, 3]) == 3
// largest(numbers: [1, 2, 3, 1]) == 1
func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    return largest
}

// Out of array of integers, return the sum of all integers. Return 0 in case the input array is empty.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3]) == 6
// sum(numbers: [1, 2, 3, 1]) == 7
func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

// Out of array of integers, return the count of all integers. Return 0 in case the input array is empty.
// count(numbers: [] as [Int]) == 0
// count(numbers: [1, 2, 3]) == 3
// count(numbers: [1, 2, 3, 1]) == 4
func count(numbers: [Int]) -> Int {
    return numbers.count
}

// Out of array of integers, return the average of all integers. Return 0 in case the input array is empty.
// average(numbers: [] as [Int]) == 0
// average(numbers: [1, 2, 3]) == 2
// average(numbers: [1, 2, 3, 1]) == 2
func average(numbers: [Int]) -> Double {
    return Double(sum(numbers: numbers)) / Double(count(numbers: numbers))
}

// Out of array of integers, return the median of all integers.
// Return nil in case the input array is empty.
// median(numbers: [] as [Int]) == nil
// median(numbers: [1, 2, 3]) == 2
// median(numbers: [1, 2, 3, 1]) == 2
// median(numbers: [1, 2, 3, 4]) == 2.5
func median(numbers: [Int]) -> Double? {
    if numbers.isEmpty {
        return nil
    }
    let sortedNumbers = numbers.sorted()
    let count = sortedNumbers.count
    if count % 2 == 0 {
        let middleIndex = count / 2
        return Double(sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2
    } else {
        let middleIndex = count / 2
        return Double(sortedNumbers[middleIndex])
    }
}

// Out of array of integers, return the mode of all integers.
// Return nil in case the input array is empty.
// mode(numbers: [] as [Int]) == nil
// mode(numbers: [1, 2, 3]) == nil
// mode(numbers: [1, 2, 3, 1]) == 1
// mode(numbers: [1, 2, 3, 4]) == 1
// mode(numbers: [1, 2, 3, 4, 1, 2, 3, 4, 1, 

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

func longest(strings: [String?]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if let string = string, string.count > longest!.count {
            longest = string
        }
    }
    
    return longest
}

func longest(strings: [String]) -> String {
    if strings.isEmpty {
        fatalError("Input array cannot be empty")
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

func longest(strings: [String?]) -> String {
    if strings.isEmpty {
        fatalError("Input array cannot be empty")
    }
    
    var longest = strings[0]
    
    for string in strings {
        if let string = string, string.count > longest!.count {
            longest = string
        }
    }
    
    return longest!
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String?]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if let string = string, string.count > longest!.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String {
    if strings.isEmpty {
        fatalError("Input array cannot be empty")
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String?]) -> String {
    if strings.isEmpty {
        fatalError("Input array cannot be empty")
    }
    
    var longest = strings[0]
    
    for string in strings {
        if let string = string, string.count > longest!.count {
            longest = string
        }
    }
    
    return longest!
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String {
    if strings.isEmpty {
        fatalError("Input array cannot be empty")
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String?]) -> String {
    if strings.isEmpty {
        fatalError("Input array cannot be empty")
    }
    
    var longest = strings[0]
    
    for string in strings {
        if let string = string, string.count > longest!.count {
            longest = string
        }
    }
    
    return longest!
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String {
    if strings.isEmpty {
        fatalError("Input array cannot be empty

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    return smallest
}

func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    return largest
}

func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

func average(numbers: [Int]) -> Double {
    return Double(sum(numbers: numbers)) / Double(numbers.count)
}

func median(numbers: [Int]) -> Double {
    if numbers.isEmpty {
        return 0
    }
    let sortedNumbers = numbers.sorted()
    let middleIndex = sortedNumbers.count / 2
    if sortedNumbers.count % 2 == 0 {
        return Double(sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2
    } else {
        return Double(sortedNumbers[middleIndex])
    }
}

func positiveCount(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number > 0 {
            count += 1
        }
    }
    return count
}

func negativeCount(numbers: [Int]) -> Int {
    return numbers.filter{$0 < 0}.count
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of numbers, return the smallest one. Return the first one in case of multiple
// numbers of the same value. Return nil in case the input array is empty.
// smallest(numbers: [] as [Int]) == nil
// smallest(numbers: [1, 2, 3]) == 1
// smallest(numbers: [1, 2, 3, 1]) == 1
func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    return smallest
}

// Out of array of numbers, return the largest one. Return the first one in case of multiple
// numbers of the same value. Return nil in case the input array is empty.
// largest(numbers: [] as [Int]) == nil
// largest(numbers: [1, 2, 3]) == 3
// largest(numbers: [1, 2, 3, 1]) == 1
func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    return largest
}

// Out of array of numbers, return the sum of all numbers. Return 0 in case the input array is
// empty.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3]) == 6
// sum(numbers: [1, 2, 3, 4, 5]) == 15
func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

// Out of array of numbers, return the average of all numbers. Return 0 in case the input array
// is empty.
// average(numbers: [] as [Int]) == 0
// average(numbers: [1, 2, 3]) == 2
// average(numbers: [1, 2, 3, 4, 5]) == 3
func average(numbers: [Int]) -> Double {
    return Double(sum(numbers: numbers)) / Double(numbers.count)
}

// Out of array of numbers, return the median of all numbers. Return 0 in case the input array
// is empty.
// median(numbers: [] as [Int]) == 0
// median(numbers: [1, 2, 3]) == 2
// median(numbers: [1, 2, 3, 4, 5]) == 3
func median(numbers: [Int]) -> Double {
    if numbers.isEmpty {
        return 0
    }
    let sortedNumbers = numbers.sorted()
    let middleIndex = sortedNumbers.count / 2
    if sortedNumbers.count % 2 == 0 {
        return Double(sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2
    } else {
        return Double(sortedNumbers[middleIndex])
    }
}

// Out of array of numbers, return the count of all positive numbers. Return 0 in case the input
// array is empty.
// positiveCount(numbers: [] as [Int]) == 0
// positiveCount(numbers: [-1, 0, 1]) == 1
// positiveCount(numbers: [-1, 0, 1, -2, 3]) == 3
func positiveCount(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number > 0 {
            count += 1
        }
    }
    return count
}

// Out of array of numbers, return the count of all negative numbers. Return 0 in case the input
// array is empty.
// negativeCount(numbers: [] as [Int]) == 0
// negativeCount(numbers: [-1, 0, 1]) == 0
// negativeCount(numbers: [-1, 0, 1, -2, 3]) == 2
func negativeCount(numbers: [Int]) -> Int {
    return numbers.filter{$0 < 0}.count
}

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    return smallest
}

func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    return largest
}

func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

func count(numbers: [Int]) -> Int {
    return numbers.count
}

func countEven(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 2 == 0 {
            count += 1
        }
    }
    return count
}

func countOdd(numbers: [Int]) -> Int {
    return count(numbers: numbers) - countEven(numbers: numbers)
}

func countPositive(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number > 0 {
            count += 1
        }
    }
    return count
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of integers, return the smallest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// smallest(numbers: [] as [Int]) == nil
// smallest(numbers: [1, 2, 3]) == 1
// smallest(numbers: [3, 2, 1]) == 1
func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    return smallest
}

// Out of array of integers, return the largest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// largest(numbers: [] as [Int]) == nil
// largest(numbers: [1, 2, 3]) == 3
// largest(numbers: [3, 2, 1]) == 3
func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    return largest
}

// Out of array of integers, return the sum of all integers. Return 0 in case the input array is
// empty.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3]) == 6
// sum(numbers: [-1, 0, 1]) == 0
func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

// Out of array of integers, return the count of all integers. Return 0 in case the input array is
// empty.
// count(numbers: [] as [Int]) == 0
// count(numbers: [1, 2, 3]) == 3
// count(numbers: [-1, 0, 1]) == 3
func count(numbers: [Int]) -> Int {
    return numbers.count
}

// Out of array of integers, return the count of all even integers. Return 0 in case the input
// array is empty.
// countEven(numbers: [] as [Int]) == 0
// countEven(numbers: [1, 2, 3]) == 0
// countEven(numbers: [-1, 0, 1]) == 1
func countEven(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 2 == 0 {
            count += 1
        }
    }
    return count
}

// Out of array of integers, return the count of all odd integers. Return 0 in case the input
// array is empty.
// countOdd(numbers: [] as [Int]) == 0
// countOdd(numbers: [1, 2, 3]) == 3
// countOdd(numbers: [-1, 0, 1]) == 2
func countOdd(numbers: [Int]) -> Int {
    return count(numbers: numbers) - countEven(numbers: numbers)
}

// Out of array of integers, return the count of all positive integers. Return 0 in case the input
// array is empty.
// countPositive(numbers: [] as [Int]) == 0
// countPositive(numbers: [1, 2, 3]) == 3
// countPositive(numbers: [-1, 0, 1]) == 1
func countPositive(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number > 0 {
            count += 1
        }
    }
    return count
}

// Out of array of integers, return the count of all negative integers. Return 0 in case the input
// array is empty.
// countNegative(numbers: [] as [Int]) == 0
// countNegative(numbers: [1, 2, 3]) == 0
// countNegative(numbers: [-1, 0, 1]) == 3
func countNegative(numbers

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

func longest2(strings: [String]) -> String? {
    return strings.reduce(nil) {
        $0 == nil? $1 : ($1?.count > $0!.count? $1 : $0)
    }
}

func longest3(strings: [String]) -> String? {
    return strings.reduce("") {
        $0.count > $1.count? $0 : $1
    }
}

func longest4(strings: [String]) -> String? {
    return strings.reduce("", combine: {
        $0.count > $1.count? $0 : $1
    })
}

func longest5(strings: [String]) -> String? {
    return strings.reduce("", {
        $0.count > $1.count? $0 : $1
    })
}

func longest6(strings: [String]) -> String? {
    return strings.reduce("", {
        $0.count > $1.count? $0 : $1
    })
}

func longest7(strings: [String]) -> String? {
    return strings.reduce("", {
        $0.count > $1.count? $0 : $1
    })
}

func longest8(strings: [String]) -> String? {
    return strings.reduce("", {
        $0.count > $1.count? $0 : $1
    })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest2(strings: [String]) -> String? {
    return strings.reduce(nil) {
        $0 == nil? $1 : ($1?.count > $0!.count? $1 : $0)
    }
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest3(strings: [String]) -> String? {
    return strings.reduce("") {
        $0.count > $1.count? $0 : $1
    }
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest4(strings: [String]) -> String? {
    return strings.reduce("", combine: {
        $0.count > $1.count? $0 : $1
    })
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest5(strings: [String]) -> String? {
    return strings.reduce("", {
        $0.count > $1.count? $0 : $1
    })
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest6(strings: [String]) -> String? {
    return strings.reduce("", {
        $0.count > $1.count? $0 : $1
    })
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest7(strings: [String]) -> String? {
    return strings.reduce("", {
        $0.count > $1.count? $0 : $1
    })
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest8(strings: [String]) -> String? {
    return strings.reduce("", {
        $0.count > $1.count? $0 : $1
    })
}

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var smallest = numbers[0]
    
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    
    return smallest
}

func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var largest = numbers[0]
    
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    
    return largest
}

func sum(numbers: [Int]) -> Int {
    var sum = 0
    
    for number in numbers {
        sum += number
    }
    
    return sum
}

func countPositive(numbers: [Int]) -> Int {
    var count = 0
    
    for number in numbers {
        if number > 0 {
            count += 1
        }
    }
    
    return count
}

func countNegative(numbers: [Int]) -> Int {
    return countPositive(numbers: numbers.map { -$0 })
}

func countZeros(numbers: [Int]) -> Int {
    return countPositive(numbers: numbers.map { $0 == 0? 1 : 0 })
}

func countFives(numbers: [Int]) -> Int {
    return countPositive(numbers: numbers.map { $0 % 5 == 0? 1 : 0 })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of integers, return the smallest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// smallest(numbers: [] as [Int]) == nil
// smallest(numbers: [1, 2, 3]) == 1
// smallest(numbers: [1, 2, 3, 1]) == 1
func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var smallest = numbers[0]
    
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    
    return smallest
}

// Out of array of integers, return the largest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// largest(numbers: [] as [Int]) == nil
// largest(numbers: [1, 2, 3]) == 3
// largest(numbers: [1, 2, 3, 1]) == 1
func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var largest = numbers[0]
    
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    
    return largest
}

// Out of array of integers, return the sum of all the values. Return 0 in case the input
// array is empty.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3]) == 6
// sum(numbers: [1, 2, 3, 1]) == 4
func sum(numbers: [Int]) -> Int {
    var sum = 0
    
    for number in numbers {
        sum += number
    }
    
    return sum
}

// Out of array of integers, return the count of all positive values. Return 0 in case the
// input array is empty.
// countPositive(numbers: [] as [Int]) == 0
// countPositive(numbers: [1, 2, 3]) == 3
// countPositive(numbers: [1, 2, 3, -1]) == 3
func countPositive(numbers: [Int]) -> Int {
    var count = 0
    
    for number in numbers {
        if number > 0 {
            count += 1
        }
    }
    
    return count
}

// Out of array of integers, return the count of all negative values. Return 0 in case the
// input array is empty.
// countNegative(numbers: [] as [Int]) == 0
// countNegative(numbers: [1, 2, 3]) == 0
// countNegative(numbers: [1, 2, 3, -1]) == 1
func countNegative(numbers: [Int]) -> Int {
    return countPositive(numbers: numbers.map { -$0 })
}

// Out of array of integers, return the count of all zeros. Return 0 in case the input array
// is empty.
// countZeros(numbers: [] as [Int]) == 0
// countZeros(numbers: [1, 2, 3]) == 0
// countZeros(numbers: [0, 0, 0, 1]) == 1
func countZeros(numbers: [Int]) -> Int {
    return countPositive(numbers: numbers.map { $0 == 0? 1 : 0 })
}

// Out of array of integers, return the count of all values that can be divided by 5. Return
// 0 in case the input array is empty.
// countFives(numbers: [] as [Int]) == 0
// countFives(numbers: [1, 2, 3]) == 0
// countFives(numbers: [1, 2, 3, 5]) == 1
// countFives(numbers: [1, 2, 3, 5, 5, 5]) == 3
func countFives(numbers: [Int]) -> Int {
    return countPositive(numbers: numbers.map { $0 % 5 == 0? 1 : 0 })
}

// Out of array of integers, return the count of all

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    
    return smallest
}

func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    
    return largest
}

func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    
    return sum
}

func count(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 3 == 0 {
            count += 1
        }
    }
    
    return count
}

func unique(numbers: [Int]) -> Int {
    var unique = Set<Int>()
    for number in numbers {
        unique.insert(number)
    }
    
    return unique.count
}

func negative(numbers: [Int]) -> Int {
    var negative = 0
    for number in numbers {
        if number < 0 {
            negative += 1
        }
    }
    
    return negative
}

func positive(numbers: [Int]) -> Int {
    return count(numbers: numbers.filter { $0 > 0 })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of integers, return the smallest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// smallest(numbers: [] as [Int]) == nil
// smallest(numbers: [1, 2, 3]) == 1
// smallest(numbers: [1, 2, 3, 1]) == 1
func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    
    return smallest
}

// Out of array of integers, return the largest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// largest(numbers: [] as [Int]) == nil
// largest(numbers: [1, 2, 3]) == 3
// largest(numbers: [1, 2, 3, 1]) == 1
func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    
    return largest
}

// Out of array of integers, return the sum of all integers. Return 0 in case the input array is
// empty.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3]) == 6
// sum(numbers: [1, 2, 3, 4]) == 10
func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    
    return sum
}

// Out of array of integers, return the count of all integers that are divisible by 3. Return 0
// in case the input array is empty.
// count(numbers: [] as [Int]) == 0
// count(numbers: [1, 2, 3]) == 0
// count(numbers: [1, 2, 3, 4]) == 1
func count(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 3 == 0 {
            count += 1
        }
    }
    
    return count
}

// Out of array of integers, return the count of all unique integers. Return 0 in case the input
// array is empty.
// unique(numbers: [] as [Int]) == 0
// unique(numbers: [1, 2, 3]) == 3
// unique(numbers: [1, 2, 3, 1, 2, 3]) == 3
func unique(numbers: [Int]) -> Int {
    var unique = Set<Int>()
    for number in numbers {
        unique.insert(number)
    }
    
    return unique.count
}

// Out of array of integers, return the count of all negative integers. Return 0 in case the input
// array is empty.
// negative(numbers: [] as [Int]) == 0
// negative(numbers: [1, 2, 3]) == 0
// negative(numbers: [-1, -2, -3]) == 3
func negative(numbers: [Int]) -> Int {
    var negative = 0
    for number in numbers {
        if number < 0 {
            negative += 1
        }
    }
    
    return negative
}

// Out of array of integers, return the count of all positive integers. Return 0 in case the input
// array is empty.
// positive(numbers: [] as [Int]) == 0
// positive(numbers: [1, 2, 3]) == 3
// positive(numbers: [-1, -2, -3]) == 0
func positive(numbers: [Int]) -> Int {
    return count(numbers: numbers.filter { $0 > 0 })
}

// Out of array of integers, return the count of all even integers. Return 0 in case the input
// array is empty.
// even(numbers: [] as [Int]) == 0
// even(numbers: [1

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    return smallest
}

func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    return largest
}

func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

func count(numbers: [Int]) -> Int {
    return numbers.count
}

func countEven(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 2 == 0 {
            count += 1
        }
    }
    return count
}

func countOdd(numbers: [Int]) -> Int {
    return countEven(numbers: numbers) - count(numbers: numbers)
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of integers, return the smallest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// smallest(numbers: [] as [Int]) == nil
// smallest(numbers: [1, 2, 3]) == 1
// smallest(numbers: [1, 2, 3, 1]) == 1
func smallest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var smallest = numbers[0]
    for number in numbers {
        if number < smallest {
            smallest = number
        }
    }
    return smallest
}

// Out of array of integers, return the largest one. Return the first one in case of multiple
// integers of the same value. Return nil in case the input array is empty.
// largest(numbers: [] as [Int]) == nil
// largest(numbers: [1, 2, 3]) == 3
// largest(numbers: [1, 2, 3, 1]) == 1
func largest(numbers: [Int]) -> Int? {
    if numbers.isEmpty {
        return nil
    }
    
    var largest = numbers[0]
    for number in numbers {
        if number > largest {
            largest = number
        }
    }
    return largest
}

// Out of array of integers, return the sum of all integers. Return 0 in case the input array is empty.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3]) == 6
// sum(numbers: [1, 2, 3, 1]) == 7
func sum(numbers: [Int]) -> Int {
    var sum = 0
    for number in numbers {
        sum += number
    }
    return sum
}

// Out of array of integers, return the count of all integers. Return 0 in case the input array is empty.
// count(numbers: [] as [Int]) == 0
// count(numbers: [1, 2, 3]) == 3
// count(numbers: [1, 2, 3, 1]) == 4
func count(numbers: [Int]) -> Int {
    return numbers.count
}

// Out of array of integers, return the count of even integers. Return 0 in case the input array is empty.
// countEven(numbers: [] as [Int]) == 0
// countEven(numbers: [1, 2, 3]) == 0
// countEven(numbers: [1, 2, 3, 4]) == 2
func countEven(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number % 2 == 0 {
            count += 1
        }
    }
    return count
}

// Out of array of integers, return the count of odd integers. Return 0 in case the input array is empty.
// countOdd(numbers: [] as [Int]) == 0
// countOdd(numbers: [1, 2, 3]) == 3
// countOdd(numbers: [1, 2, 3, 4]) == 1
func countOdd(numbers: [Int]) -> Int {
    return countEven(numbers: numbers) - count(numbers: numbers)
}

// Out of array of integers, return the count of prime integers. Return 0 in case the input array is empty.
// countPrime(numbers: [] as [Int]) == 0
// countPrime(numbers: [1, 2, 3]) == 0
// countPrime(numbers: [1, 2, 3, 4]) == 1
// countPrime(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 4
func countPrime(numbers: [Int]) -> Int {
    var count = 0
    for number in numbers {
        if number > 1 {
            var isPrime = true
            for i in 2...Int(sqrt(Double(number))) {
                if number % i == 0 {
                    isPrime = false
                    break
                }
            }
            if isPrime {
                count += 1
            }

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

func longest(_ strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

func longest(_ strings: [String]?) -> String? {
    guard let strings = strings else {
        return nil
    }
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(_ strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(_ strings: [String]?) -> String? {
    guard let strings = strings else {
        return nil
    }
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(_ strings: [String]?) -> String? {
    guard let strings = strings else {
        return nil
    }
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(_ strings: [String]?) -> String? {
    guard let strings = strings else {
        return nil
    }
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(_ strings: [String]?) -> String? {
    guard let strings = strings else {
        return nil
    }
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(_ strings: [String]?) -> String? {
   

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    if a == 0 {
        return b
    }
    return greatestCommonDivisor(a: b % a, b: a)
}

func leastCommonMultiple(a: Int, b: Int) -> Int {
    return a * b / greatestCommonDivisor(a: a, b: b)
}

func leastCommonMultiple(of numbers: [Int]) -> Int {
    return numbers.reduce(1, *) { leastCommonMultiple(a: $0, b: $1) }
}

func sumOfNumbersUpTo(n: Int) -> Int {
    return (1...n).reduce(0, +)
}

func sumOfSquaresUpTo(n: Int) -> Int {
    return (1...n).map { $0 * $0 }.reduce(0, +)
}

func squareOfSumUpTo(n: Int) -> Int {
    return sumOfNumbersUpTo(n: n) * sumOfNumbersUpTo(n: n)
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    if a == 0 {
        return b
    }
    return greatestCommonDivisor(a: b % a, b: a)
}

// Return the least common multiple of two integers a and b
// leastCommonMultiple(a: 3, b: 5) == 15
// leastCommonMultiple(a: 7, b: 12) == 42
func leastCommonMultiple(a: Int, b: Int) -> Int {
    return a * b / greatestCommonDivisor(a: a, b: b)
}

// Return the least common multiple of an array of integers
// leastCommonMultiple(of: [3, 5, 7, 11]) == 315
func leastCommonMultiple(of numbers: [Int]) -> Int {
    return numbers.reduce(1, *) { leastCommonMultiple(a: $0, b: $1) }
}

// Return the sum of all the numbers between 1 and n
// sumOfNumbersUpTo(n: 5) == 15
// sumOfNumbersUpTo(n: 10) == 55
func sumOfNumbersUpTo(n: Int) -> Int {
    return (1...n).reduce(0, +)
}

// Return the sum of all the squares between 1 and n
// sumOfSquaresUpTo(n: 5) == 55
// sumOfSquaresUpTo(n: 10) == 385
func sumOfSquaresUpTo(n: Int) -> Int {
    return (1...n).map { $0 * $0 }.reduce(0, +)
}

// Return the square of the sum of all the numbers between 1 and n
// squareOfSumUpTo(n: 5) == 55
// squareOfSumUpTo(n: 10) == 385
func squareOfSumUpTo(n: Int) -> Int {
    return sumOfNumbersUpTo(n: n) * sumOfNumbersUpTo(n: n)
}

// Print the result of the exercise
print("Greatest common divisor:", greatestCommonDivisor(a: 3, b: 5))
print("Least common multiple:", leastCommonMultiple(a: 3, b: 5))
print("Least common multiple of 7, 12, 15, 20:", leastCommonMultiple(of: [7, 12, 15, 20]))
print("Sum of numbers up to 10:", sumOfNumbersUpTo(n: 10))
print("Sum of squares up to 10:", sumOfSquaresUpTo(n: 10))
print("Square of sum up to 10:", squareOfSumUpTo(n: 10))

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }

    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Calculate the GCD using the greatestCommonDivisor function
    let gcd = greatestCommonDivisor(a: a, b: b)

    // Return the product of the two numbers divided by the GCD
    return (a / gcd) * b
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }

    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

// Return the least common multiple of two integers a and b
// leastCommonMultiple(a: 3, b: 5) == 15
// leastCommonMultiple(a: 7, b: 12) == 42
func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Calculate the GCD using the greatestCommonDivisor function
    let gcd = greatestCommonDivisor(a: a, b: b)

    // Return the product of the two numbers divided by the GCD
    return (a / gcd) * b
}

// Test the greatestCommonDivisor and leastCommonMultiple functions
greatestCommonDivisor(a: 3, b: 5)  // Returns 1
leastCommonMultiple(a: 3, b: 5)   // Returns 15
greatestCommonDivisor(a: 7, b: 12) // Returns 1
leastCommonMultiple(a: 7, b: 12)  // Returns 42
```

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }
    
    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Use the GCD to calculate the LCM
    return a * b / greatestCommonDivisor(a: a, b: b)
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }
    
    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

// Return the least common multiple of two integers a and b
// leastCommonMultiple(a: 3, b: 5) == 15
// leastCommonMultiple(a: 7, b: 12) == 42
func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Use the GCD to calculate the LCM
    return a * b / greatestCommonDivisor(a: a, b: b)
}

// Test the function
print(greatestCommonDivisor(a: 3, b: 5)) // Output: 1
print(greatestCommonDivisor(a: 25, b: 15)) // Output: 5
print(leastCommonMultiple(a: 3, b: 5)) // Output: 15
print(leastCommonMultiple(a: 7, b: 12)) // Output: 42
```

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }

    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Use the GCD to calculate the multiplication factor
    let multiplicationFactor = greatestCommonDivisor(a: a, b: b)

    // Return the least common multiple using the multiplication factor
    return multiplicationFactor == 0? 0 : a * b / multiplicationFactor
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }

    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

// Return the least common multiple of two integers a and b
// leastCommonMultiple(a: 3, b: 5) == 15
// leastCommonMultiple(a: 7, b: 12) == 42
func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Use the GCD to calculate the multiplication factor
    let multiplicationFactor = greatestCommonDivisor(a: a, b: b)

    // Return the least common multiple using the multiplication factor
    return multiplicationFactor == 0? 0 : a * b / multiplicationFactor
}

// Test the function
print(greatestCommonDivisor(a: 3, b: 5)) // Output: 1
print(greatestCommonDivisor(a: 25, b: 15)) // Output: 5
print(leastCommonMultiple(a: 3, b: 5)) // Output: 15
print(leastCommonMultiple(a: 7, b: 12)) // Output: 42
```

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }

    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Calculate the GCD
    let gcd = greatestCommonDivisor(a: a, b: b)

    // Calculate the LCM using the formula: lcm * gcd = a * b
    return a * b / gcd
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }

    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

// Return the least common multiple of two integers a and b
// leastCommonMultiple(a: 3, b: 5) == 15
// leastCommonMultiple(a: 7, b: 12) == 42
func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Calculate the GCD
    let gcd = greatestCommonDivisor(a: a, b: b)

    // Calculate the LCM using the formula: lcm * gcd = a * b
    return a * b / gcd
}

// Example usage
print(greatestCommonDivisor(a: 3, b: 5)) // Output: 1
print(greatestCommonDivisor(a: 25, b: 15)) // Output: 5
print(leastCommonMultiple(a: 3, b: 5)) // Output: 15
print(leastCommonMultiple(a: 7, b: 12)) // Output: 42
```

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }
    
    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Use the GCD to calculate the multiplication factor
    let multiplicationFactor = greatestCommonDivisor(a: a, b: b)
    
    // Return the least common multiple using the multiplication factor
    return a * b / multiplicationFactor
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }
    
    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

// Return the least common multiple of two integers a and b
// leastCommonMultiple(a: 3, b: 5) == 15
// leastCommonMultiple(a: 7, b: 12) == 42
func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Use the GCD to calculate the multiplication factor
    let multiplicationFactor = greatestCommonDivisor(a: a, b: b)
    
    // Return the least common multiple using the multiplication factor
    return a * b / multiplicationFactor
}

// Test the function
print(greatestCommonDivisor(a: 3, b: 5)) // Output: 1
print(greatestCommonDivisor(a: 25, b: 15)) // Output: 5
print(leastCommonMultiple(a: 3, b: 5)) // Output: 15
print(leastCommonMultiple(a: 7, b: 12)) // Output: 42
```

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }
    
    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }
    
    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

// Test the function
print(greatestCommonDivisor(a: 3, b: 5)) // Output: 1
print(greatestCommonDivisor(a: 25, b: 15)) // Output: 5
```

The `greatestCommonDivisor` function takes two integer parameters `a` and `b` and returns their greatest common divisor. The base case checks if one of the numbers is 0, and returns the other number as the GCD. The recursive case calculates the remainder of `a` divided by `b` using the modulo operator `%`, and recursively calls the function with the updated values of `a` and `b`.

The `print` function is used to output the results of the `greatestCommonDivisor` function.

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    if a == 0 {
        return b
    }
    return greatestCommonDivisor(a: b % a, b: a)
}

func leastCommonMultiple(a: Int, b: Int) -> Int {
    return a * b / greatestCommonDivisor(a: a, b: b)
}

func sumOfNumbers(n: Int) -> Int {
    if n == 1 {
        return 1
    }
    return n + sumOfNumbers(n: n - 1)
}

func sumOfEvenNumbers(n: Int) -> Int {
    if n == 1 {
        return 0
    }
    if n % 2 == 0 {
        return n + sumOfEvenNumbers(n: n - 1)
    } else {
        return sumOfEvenNumbers(n: n - 1)
    }
}

func sumOfOddNumbers(n: Int) -> Int {
    if n == 1 {
        return 1
    }
    if n % 2 == 1 {
        return n + sumOfOddNumbers(n: n - 1)
    } else {
        return sumOfOddNumbers(n: n - 1)
    }
}

func sumOfNumbersDivisibleBy(n: Int) -> Int {
    if n == 1 {
        return 0
    }
    if n % 3 == 0 && n % 2 == 0 {
        return n + sumOfNumbersDivisibleBy(n: n - 1)
    } else {
        return sumOfNumbersDivisibleBy(n: n - 1)
    }
}

func sumOfPrimes(n: Int) -> Int {
    if n == 1 {
        return 0
    }
    if isPrime(n: n) {
        return n + sumOfPrimes(n: n - 1)
    } else {
        return sumOfPrimes(n: n - 1)
    }
}

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func sumOfFibonacciNumbers(n: Int) -> Int {
    if n == 1 {
        return 0
    }
    if n == 2 {
        return 1
    }
    return sumOfFibonacciNumbers(n: n - 1) + sumOfFibonacciNumbers(n: n - 2)
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    if a == 0 {
        return b
    }
    return greatestCommonDivisor(a: b % a, b: a)
}

// Return the least common multiple of two integers a and b
// leastCommonMultiple(a: 3, b: 5) == 15
// leastCommonMultiple(a: 7, b: 12) == 42
func leastCommonMultiple(a: Int, b: Int) -> Int {
    return a * b / greatestCommonDivisor(a: a, b: b)
}

// Return the sum of all numbers between 1 and n
// sumOfNumbers(n: 5) == 15
// sumOfNumbers(n: 10) == 55
func sumOfNumbers(n: Int) -> Int {
    if n == 1 {
        return 1
    }
    return n + sumOfNumbers(n: n - 1)
}

// Return the sum of all even numbers between 1 and n
// sumOfEvenNumbers(n: 5) == 0
// sumOfEvenNumbers(n: 10) == 30
func sumOfEvenNumbers(n: Int) -> Int {
    if n == 1 {
        return 0
    }
    if n % 2 == 0 {
        return n + sumOfEvenNumbers(n: n - 1)
    } else {
        return sumOfEvenNumbers(n: n - 1)
    }
}

// Return the sum of all odd numbers between 1 and n
// sumOfOddNumbers(n: 5) == 5
// sumOfOddNumbers(n: 10) == 25
func sumOfOddNumbers(n: Int) -> Int {
    if n == 1 {
        return 1
    }
    if n % 2 == 1 {
        return n + sumOfOddNumbers(n: n - 1)
    } else {
        return sumOfOddNumbers(n: n - 1)
    }
}

// Return the sum of all numbers between 1 and n that are divisible by either 2 or 3
// sumOfNumbersDivisibleBy(n: 5) == 3
// sumOfNumbersDivisibleBy(n: 10) == 23
func sumOfNumbersDivisibleBy(n: Int) -> Int {
    if n == 1 {
        return 0
    }
    if n % 3 == 0 && n % 2 == 0 {
        return n + sumOfNumbersDivisibleBy(n: n - 1)
    } else {
        return sumOfNumbersDivisibleBy(n: n - 1)
    }
}

// Return the sum of all prime numbers between 1 and n
// sumOfPrimes(n: 5) == 2
// sumOfPrimes(n: 10) == 7
func sumOfPrimes(n: Int) -> Int {
    if n == 1 {
        return 0
    }
    if isPrime(n: n) {
        return n + sumOfPrimes(n: n - 1)
    } else {
        return sumOfPrimes(n: n - 1)
    }
}

// Return true if n is prime, false otherwise
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the sum of all Fibonacci numbers between 1 and n
// sumOfFibonacciNumbers(n: 5) == 5
// sumOfFibonacciNumbers(n: 10) == 12
func sumOfFibonacciNumbers(n: Int) -> Int {
    if n == 1 {
        return 0
    }
    if n == 2 {
        return 1
    }
    return sumOfFibonacciNumbers(n: n - 1) + sumOfFibonacciNumbers(n: n - 2)
}

// Return the sum of all palindromic numbers between 1 and n
// sumOfPalindromicNumbers(n: 5) == 0
// sumOfPalindromicNumbers(n: 10) == 36
func sumOfPalindromicNumbers(n: Int) -> Int {
   

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if b is 0, the answer is a
    if b == 0 {
        return a
    }
    // Recursive case: compute the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Compute the GCD
    let gcd = greatestCommonDivisor(a: a, b: b)
    // Return the LCM using the formula LCM * GCD = a * b
    return a / gcd * b
}

func leastCommonMultiple(of numbers: [Int]) -> Int {
    // Base case: if the array contains only one number, return that number
    if numbers.count == 1 {
        return numbers[0]
    }
    // Recursive case:
    // Divide the array into two halves
    let mid = numbers.count / 2
    let leftHalf = Array(numbers[0..<mid])
    let rightHalf = Array(numbers[mid..<numbers.count])
    // Find the LCM of the two halves
    let lcmOfLeftHalf = leastCommonMultiple(of: leftHalf)
    let lcmOfRightHalf = leastCommonMultiple(of: rightHalf)
    // Find the LCM of the two halves combined
    let lcmOfBoth = leastCommonMultiple(a: lcmOfLeftHalf, b: lcmOfRightHalf)
    // Return the LCM of the original array and the LCM of the two halves combined
    return leastCommonMultiple(a: numbers[0], b: lcmOfBoth)
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if b is 0, the answer is a
    if b == 0 {
        return a
    }
    // Recursive case: compute the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

// Return the least common multiple of two integers a and b
// leastCommonMultiple(a: 3, b: 5) == 15
// leastCommonMultiple(a: 7, b: 12) == 42
func leastCommonMultiple(a: Int, b: Int) -> Int {
    // Compute the GCD
    let gcd = greatestCommonDivisor(a: a, b: b)
    // Return the LCM using the formula LCM * GCD = a * b
    return a / gcd * b
}

// Return the least common multiple of an array of integers
// leastCommonMultiple(of: [2, 3, 4, 5]) == 60
func leastCommonMultiple(of numbers: [Int]) -> Int {
    // Base case: if the array contains only one number, return that number
    if numbers.count == 1 {
        return numbers[0]
    }
    // Recursive case:
    // Divide the array into two halves
    let mid = numbers.count / 2
    let leftHalf = Array(numbers[0..<mid])
    let rightHalf = Array(numbers[mid..<numbers.count])
    // Find the LCM of the two halves
    let lcmOfLeftHalf = leastCommonMultiple(of: leftHalf)
    let lcmOfRightHalf = leastCommonMultiple(of: rightHalf)
    // Find the LCM of the two halves combined
    let lcmOfBoth = leastCommonMultiple(a: lcmOfLeftHalf, b: lcmOfRightHalf)
    // Return the LCM of the original array and the LCM of the two halves combined
    return leastCommonMultiple(a: numbers[0], b: lcmOfBoth)
}

// Example usage
print(greatestCommonDivisor(a: 36, b: 48)) // Output: 12
print(leastCommonMultiple(a: 3, b: 5)) // Output: 15
print(leastCommonMultiple(of: [2, 3, 4, 5])) // Output: 60

func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }
    
    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

```swift
// Return a greatest common divisor of two integers a and b
// greatestCommonDivisor(a: 3, b: 5) == 1
// greatestCommonDivisor(a: 25, b: 15) == 5
func greatestCommonDivisor(a: Int, b: Int) -> Int {
    // Base case: if one of the numbers is 0, the other number is the GCD
    if a == 0 {
        return b
    }
    if b == 0 {
        return a
    }
    
    // Recursive case: calculate the GCD using the Euclidean algorithm
    return greatestCommonDivisor(a: b, b: a % b)
}

// Test the function
print(greatestCommonDivisor(a: 3, b: 5)) // Output: 1
print(greatestCommonDivisor(a: 25, b: 15)) // Output: 5
```

The `greatestCommonDivisor` function takes two integer parameters `a` and `b` and returns their greatest common divisor. The base case checks if one of the numbers is 0, and returns the other number as the GCD. The recursive case calculates the remainder of `a` divided by `b` using the modulo operator `%`, and recursively calls the function with `b` and the remainder as the input parameters. The returned value from the recursive call is then used as the input parameter for the next recursive call.

The `greatestCommonDivisor` function is called with the test cases from the provided code, and the output is printed to the console.

func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            substrings.append(suffix)
        }
    }
    return substrings
}

func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            if!substrings.contains(suffix) {
                substrings.append(suffix)
            }
        }
    }
    return substrings
}

func longestPalindrome(string: String) -> String {
    var longest = ""
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            if suffix == String(suffix.reversed()) && suffix.count > longest.count {
                longest = suffix
            }
        }
    }
    return longest
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            substrings.append(suffix)
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            if!substrings.contains(suffix) {
                substrings.append(suffix)
            }
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            if!substrings.contains(suffix) {
                substrings.append(suffix)
            }
        }
    }
    return substrings
}

// Return the longest palindrome substring of the input string
// longestPalindrome(string: "abracadabraanamadamalayalamradar") == "anamadamalayalam"
func longestPalindrome(string: String) -> String {
    var longest = ""
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            if suffix == String(suffix.reversed()) && suffix.count > longest.count {
                longest = suffix
            }
        }
    }
    return longest
}

// Return the longest palindrome substring of the input string
// longestPalindrome(string: "abracadabraanamadamalayalamradar") == "anamadamalayalam"
func longestPalindrome(string: String) -> String {
    var longest = ""
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            if suffix == String(suffix.reversed()) && suffix.count > longest.count {
                longest = suffix
            }
        }
    }
    return longest
}

// Return the longest palindrome substring of the input string
// longestPalindrome(string: "abracadabraanamadamalayalamradar") == "anamadamalayalam"
func longestPalindrome(string: String) -> String {
    var longest = ""
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            if suffix == String(suffix.reversed()) && suffix.count > longest.count {
                longest = suffix
            }
        }
    }
    return longest
}

// Return the longest palindrome substring of the input string
// longestPalindrome(string: "abracadabraanamadamalayalamradar") == "anamadamalayalam"

func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for prefix in allPrefixes(string: string) {
        for suffix in allSuffixes(string: string) {
            substrings.append(prefix + suffix)
        }
    }
    return substrings
}

func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for prefix in allPrefixes(string: string) {
        for suffix in allSuffixes(string: string) {
            if Set(suffix).count == suffix.count {
                substrings.append(prefix + suffix)
            }
        }
    }
    return substrings
}

func allUniqueSubstrings2(string: String) -> [String] {
    var substrings = [String]()
    var suffixes = [String]()
    for char in string {
        suffixes.append(String(char))
        for suffix in suffixes {
            if Set(suffix).count == suffix.count {
                substrings.append(suffix)
            }
        }
    }
    return substrings
}

func allUniqueSubstrings3(string: String) -> [String] {
    var substrings = [String]()
    var suffixes = [String]()
    var lastChar = Character("")
    for char in string {
        if char!= lastChar {
            suffixes.append(String(char))
            for suffix in suffixes {
                if Set(suffix).count == suffix.count {
                    substrings.append(suffix)
                }
            }
        }
        lastChar = char
    }
    return substrings
}

func allUniqueSubstrings4(string: String) -> [String] {
    var substrings = [String]()
    var suffixes = [String]()
    var lastChar = Character("")
    for char in string {
        if char!= lastChar {
            suffixes.append(String(char))
            for suffix in suffixes {
                if Set(suffix).count == suffix.count {
                    substrings.append(suffix)
                }
            }
        }
        lastChar = char
    }
    return substrings
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for prefix in allPrefixes(string: string) {
        for suffix in allSuffixes(string: string) {
            substrings.append(prefix + suffix)
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for prefix in allPrefixes(string: string) {
        for suffix in allSuffixes(string: string) {
            if Set(suffix).count == suffix.count {
                substrings.append(prefix + suffix)
            }
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings2(string: String) -> [String] {
    var substrings = [String]()
    var suffixes = [String]()
    for char in string {
        suffixes.append(String(char))
        for suffix in suffixes {
            if Set(suffix).count == suffix.count {
                substrings.append(suffix)
            }
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings3(string: String) -> [String] {
    var substrings = [String]()
    var suffixes = [String]()
    var lastChar = Character("")
    for char in string {
        if char!= lastChar {
            suffixes.append(String(char))
            for suffix in suffixes {
                if Set(suffix).count == suffix.count {
                    substrings.append(suffix)
                }
            }
        }
        lastChar = char
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings4(string: String) -> [String] {
    var substrings = [String]()
    var suffixes = [String]()
    var lastChar = Character("")
    for char in string {
        if char!= lastChar {
            suffixes.append(String(char))
            for suffix in suffixes {
                if Set(suffix).count == suffix.count {
                    substrings.append(suffix)
                }
            }
        }
        lastChar = char
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings5(string: String) -> [String] {
    var substrings = [String]()
    var suffixes = [String]()
    var lastChar = Character("")
    for char in string {
        if char!= lastChar {
            suffixes.append(String(char))
            for suffix in suffixes {
                substrings.append(

func allPrefixes(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var prefixes = [String]()
    for i in 1...string.count {
        prefixes.append(string.prefix(i))
    }
    return prefixes
}

func allSuffixes(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var suffixes = [String]()
    for i in 1...string.count {
        suffixes.append(string.suffix(i))
    }
    return suffixes
}

func allSubstrings(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(string.substring(with: NSMakeRange(i, j-i)))
        }
    }
    return substrings
}

func allUniqueSubstrings(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = string.substring(with: NSMakeRange(i, j-i))
            if substring.count == Set(substring).count {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

func allUniqueIncreasingSubstrings(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = string.substring(with: NSMakeRange(i, j-i))
            if substring.count == Set(substring).count && substring > substrings.last {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

func allUniqueIncreasingSubstrings2(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = string.substring(with: NSMakeRange(i, j-i))
            if substring.count == Set(substring).count && isIncreasing(string: substring) {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

func isIncreasing(string: String) -> Bool {
    for i in 0...string.count-2 {
        if string[string.index(string.startIndex, offsetBy: i)] > string[string.index(string.startIndex, offsetBy: i+1)] {
            return false
        }
    }
    return true
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var prefixes = [String]()
    for i in 1...string.count {
        prefixes.append(string.prefix(i))
    }
    return prefixes
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var suffixes = [String]()
    for i in 1...string.count {
        suffixes.append(string.suffix(i))
    }
    return suffixes
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(string.substring(with: NSMakeRange(i, j-i)))
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not have repeating characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = string.substring(with: NSMakeRange(i, j-i))
            if substring.count == Set(substring).count {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not have repeating characters and are in lexicographically increasing order
// allUniqueIncreasingSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueIncreasingSubstrings(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = string.substring(with: NSMakeRange(i, j-i))
            if substring.count == Set(substring).count && substring > substrings.last {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not have repeating characters and are in lexicographically increasing order
// allUniqueIncreasingSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueIncreasingSubstrings2(string: String) -> [String] {
    if string.count == 0 {
        return []
    }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = string.substring(with: NSMakeRange(i, j-i))
            if substring.count == Set(substring).count && isIncreasing(string: substring) {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

func isIncreasing(string: String) -> Bool {
    for i in 0...string.count-2 {
        if string[string.index(string.startIndex, offsetBy: i)] > string[string.index(string.startIndex, offsetBy: i+1)] {
            return false
        }
    }
    return true
}

// Return array of all substrings from shortest to longest of the input string
// that do not have repeating characters and are in lexicographically increasing order
// allUniqueIncreasingSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueIncreasingSubstrings

func allPrefixes(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        result.append(prefix)
    }
    return result
}

func allSuffixes(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        result.append(suffix)
    }
    return result
}

func allSubstrings(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            result.append(substring)
        }
    }
    return result
}

func allSubstringsWithVowels(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            if substring.contains(where: Character.isVowel) {
                result.append(substring)
            }
        }
    }
    return result
}

func allUniqueSubstrings(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            if Set(substring).count == substring.count {
                result.append(substring)
            }
        }
    }
    return result
}

func allUniqueSubstringsWithVowels(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            if Set(substring).count == substring.count && substring.contains(where: Character.isVowel) {
                result.append(substring)
            }
        }
    }
    return result
}

func allUniqueSubstringsWithVowelsStartEnd(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            if substring.starts(with: Character.isVowel) && substring.ends(with: Character.isVowel) {
                result.append(substring)
            }
        }
    }
    return result
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        result.append(prefix)
    }
    return result
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        result.append(suffix)
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            result.append(substring)
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// that contain at least one vowel
// allSubstringsWithVowels(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstringsWithVowels(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            if substring.contains(where: Character.isVowel) {
                result.append(substring)
            }
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain any repeated characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            if Set(substring).count == substring.count {
                result.append(substring)
            }
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain any repeated characters
// and have at least one vowel
// allUniqueSubstringsWithVowels(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstringsWithVowels(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            if Set(substring).count == substring.count && substring.contains(where: Character.isVowel) {
                result.append(substring)
            }
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// that start and end with a vowel
// allUniqueSubstringsWithVowels(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstringsWithVowelsStartEnd(string: String) -> [String] {
    guard!string.isEmpty else { return [] }
    var result = [String]()
    for index in 0...string.count {
        for substring in string.prefix(index).suffix(string.count - index) {
            if substring.starts(with: Character.isVowel) && substring.ends(with: Character.isVowel) {
                result.append(substring)
            }
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// that start and end with a vowel
// and have

func allPrefixes(string: String) -> [String] {
    var prefixes: [String] = []
    var prefix = ""
    
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    
    return prefixes
}

func allSuffixes(string: String) -> [String] {
    var suffixes: [String] = []
    var suffix = ""
    
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    
    return suffixes
}

func allSubstrings(string: String) -> [String] {
    var substrings: [String] = []
    var prefix = ""
    
    for char in string {
        prefix.append(char)
        substrings.append(prefix)
    }
    
    var suffix = ""
    
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        substrings.append(suffix)
    }
    
    return substrings
}

func allUniqueSubstrings(string: String) -> [String] {
    var substrings: [String] = []
    var prefix = ""
    var seen: Set<Character> = []
    
    for char in string {
        if seen.contains(char) {
            continue
        }
        
        prefix.append(char)
        substrings.append(prefix)
        seen.insert(char)
    }
    
    var suffix = ""
    
    for char in string.reversed() {
        if seen.contains(char) {
            continue
        }
        
        suffix.insert(char, at: suffix.startIndex)
        substrings.append(suffix)
        seen.insert(char)
    }
    
    return substrings
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    var prefixes: [String] = []
    var prefix = ""
    
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    
    return prefixes
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    var suffixes: [String] = []
    var suffix = ""
    
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    
    return suffixes
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings: [String] = []
    var prefix = ""
    
    for char in string {
        prefix.append(char)
        substrings.append(prefix)
    }
    
    var suffix = ""
    
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        substrings.append(suffix)
    }
    
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings: [String] = []
    var prefix = ""
    var seen: Set<Character> = []
    
    for char in string {
        if seen.contains(char) {
            continue
        }
        
        prefix.append(char)
        substrings.append(prefix)
        seen.insert(char)
    }
    
    var suffix = ""
    
    for char in string.reversed() {
        if seen.contains(char) {
            continue
        }
        
        suffix.insert(char, at: suffix.startIndex)
        substrings.append(suffix)
        seen.insert(char)
    }
    
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings: [String] = []
    var prefix = ""
    var seen: Set<Character> = []
    
    for char in string {
        if seen.contains(char) {
            continue
        }
        
        prefix.append(char)
        substrings.append(prefix)
        seen.insert(char)
    }
    
    var suffix = ""
    
    for char in string.reversed() {
        if seen.contains(char) {
            continue
        }
        
        suffix.insert(char, at: suffix.startIndex)
        substrings.append(suffix)
        seen.insert(char)
    }
    
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings: [String] = []
    var prefix = ""
    var seen: Set<Character> = []
    
    for char in string {
        if seen.contains(char) {
            continue
        }
        
        prefix.append(char)
        substrings.append(prefix)
        seen.insert(char)
    }
    
    var suffix = ""
    
    for char in string.reversed() {
        if seen.contains(char) {
            continue
        }
        
        suffix.insert(char, at: suffix.startIndex)
        substrings.append(suffix)
        seen.insert(char)
    }
    
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings: [String] = []
    var prefix = ""
    var seen: Set<Character> = []
    
    for char

func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    
    for char in string {
        substring.append(char)
        substrings.append(substring)
    }
    return substrings
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    
    for char in string {
        substring.append(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    
    for char in string {
        substring.append(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    
    for char in string {
        substring.append(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    
    for char in string {
        substring.append(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    
    for char in string {
        substring.append(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    
    for char in string {
        substring.append(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    
    for char in string {
        substring.append(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    
    for char in string {
        substring.append(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from

func allPrefixes(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

func allSuffixes(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

func allSubstrings(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

func allUniqueSubstrings(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)])
            if!substrings.contains(substring) {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

func allUniqueSubstringsV2(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)])
            if substring.count > 2 &&!substrings.contains(substring) {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

func allUniqueSubstringsV3(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var substrings = Set<String>()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)])
            if substring.count > 2 {
                substrings.insert(substring)
            }
        }
    }
    return Array(substrings)
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string, excluding any duplicate substrings
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)])
            if!substrings.contains(substring) {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string, excluding any duplicate or substring of length 2 or less
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstringsV2(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)])
            if substring.count > 2 &&!substrings.contains(substring) {
                substrings.append(substring)
            }
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string, excluding any duplicate or substring of length 2 or less
// allUniqueSubstringsV3(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstringsV3(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var substrings = Set<String>()
    for i in 0...string.count {
        for j in i...string.count {
            let substring = String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)])
            if substring.count > 2 {
                substrings.insert(substring)
            }
        }
    }
    return Array(substrings)
}

// Return array of all substrings from shortest to longest of the input string, excluding any duplicate or substring of length 2 or less
// allUniqueSubstringsV4(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstringsV4(string: String) -> [String] {
    guard string.count > 0 else { return [] }
    var substrings = Set<String>()
    for i

func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

func allSubstrings2(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

func allSubstrings3(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

func allSubstrings4(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

func allSubstrings5(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

func allSubstrings6(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings2(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings3(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings4(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings5(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings6(string: String) -> [String] {
    var substrings = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            substrings.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return substrings
}

// Return array of all substrings from short

func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            substrings.append(suffix)
        }
    }
    return substrings
}

func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            if!substrings.contains(suffix) {
                substrings.append(suffix)
            }
        }
    }
    return substrings
}

func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    var characters = Set<Character>()
    for char in string {
        substring.append(char)
        characters.insert(char)
        substrings.append(substring)
    }
    return substrings
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    var prefixes = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        prefixes.append(prefix)
    }
    return prefixes
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    var suffixes = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        suffixes.append(suffix)
    }
    return suffixes
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            substrings.append(suffix)
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    for index in 0...string.count {
        for suffix in allSuffixes(string: String(string.suffix(index))) {
            if!substrings.contains(suffix) {
                substrings.append(suffix)
            }
        }
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    var characters = Set<Character>()
    for char in string {
        substring.append(char)
        characters.insert(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    var characters = Set<Character>()
    for char in string {
        substring.append(char)
        characters.insert(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    var characters = Set<Character>()
    for char in string {
        substring.append(char)
        characters.insert(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings = [String]()
    var substring = ""
    var characters = Set<Character>()
    for char in string {
        substring.append(char)
        characters.insert(char)
        substrings.append(substring)
    }
    return substrings
}

// Return array of all substrings from shortest to longest of the input string
// that do not contain duplicate characters
// allUniqueSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allUniqueSubstrings(string: String) -> [String] {
    var substrings =

func allPrefixes(string: String) -> [String] {
    var result = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        result.append(prefix)
    }
    return result
}

func allSuffixes(string: String) -> [String] {
    var result = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        result.append(suffix)
    }
    return result
}

func allSubstrings(string: String) -> [String] {
    var result = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            result.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return result
}

```swift
// Return array of all prefixes from shortest to longest of the input string
// allPrefixes(string: "abc") == ["a", "ab", "abc"]
func allPrefixes(string: String) -> [String] {
    var result = [String]()
    var prefix = ""
    for char in string {
        prefix.append(char)
        result.append(prefix)
    }
    return result
}

// Return array of all suffixes from shortest to longest of the input string
// allSuffixes(string: "abc") == ["c", "bc", "abc"]
func allSuffixes(string: String) -> [String] {
    var result = [String]()
    var suffix = ""
    for char in string.reversed() {
        suffix.insert(char, at: suffix.startIndex)
        result.append(suffix)
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var result = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            result.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var result = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            result.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var result = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            result.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var result = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            result.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var result = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            result.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc", "b", "bc", "c"]
func allSubstrings(string: String) -> [String] {
    var result = [String]()
    for i in 0...string.count {
        for j in i...string.count {
            result.append(String(string[string.index(string.startIndex, offsetBy: i)...string.index(string.startIndex, offsetBy: j)]))
        }
    }
    return result
}

// Return array of all substrings from shortest to longest of the input string
// allSubstrings(string: "abc") == ["a", "ab", "abc",

func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

func sumOfSquares(_ numbers: [Int]) -> Int {
    var result = 0
    for number in numbers {
        if number % 2 == 0 {
            result += number * number
        }
    }
    return result
}

func sumOfSquares(_ numbers: [Int]) -> Int {
    return numbers.filter { $0 % 2 == 0 }.map { $0 * $0 }.reduce(0, +)
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

// Return the sum of the squares of even numbers in the given array.
// sumOfSquares([1, 2, 3, 4, 5]) == 55
// sumOfSquares([10, 11, 12, 13, 14]) == 114
func sumOfSquares(_ numbers: [Int]) -> Int {
    var result = 0
    for number in numbers {
        if number % 2 == 0 {
            result += number * number
        }
    }
    return result
}

// Return the sum of the squares of even numbers in the given array.
// sumOfSquares([1, 2, 3, 4, 5]) == 55
// sumOfSquares([10, 11, 12, 13, 14]) == 114
func sumOfSquares(_ numbers: [Int]) -> Int {
    return numbers.filter { $0 % 2 == 0 }.map { $0 * $0 }.reduce(0, +)
}

// Return the sum of the squares of even numbers in the given array.
// sumOfSquares([1, 2, 3, 4, 5]) == 55
// sumOfSquares([10, 11, 12, 13, 14]) == 114
func sumOfSquares(_ numbers: [Int]) -> Int {
    return numbers.filter { $0 % 2 == 0 }.map { $0 * $0 }.reduce(0, +)
}

// Return the sum of the squares of even numbers in the given array.
// sumOfSquares([1, 2, 3, 4, 5]) == 55
// sumOfSquares([10, 11, 12, 13, 14]) == 114
func sumOfSquares(_ numbers: [Int]) -> Int {
    return numbers.filter { $0 % 2 == 0 }.map { $0 * $0 }.reduce(0, +)
}

// Return the sum of the squares of even numbers in the given array.
// sumOfSquares([1, 2, 3, 4, 5]) == 55
// sumOfSquares([10, 11, 12, 13, 14]) == 114
func sumOfSquares(_ numbers: [Int]) -> Int {
    return numbers.filter { $0 % 2 == 0 }.map { $0 * $0 }.reduce(0, +)
}

// Return the sum of the squares of even numbers in the given array.
// sumOfSquares([1, 2, 3, 4, 5]) == 55
// sumOfSquares([10, 11, 12, 13, 14]) == 114
func sumOfSquares(_ numbers: [Int]) -> Int {
    return numbers.filter { $0 % 2 == 0 }.map { $0 * $0 }.reduce(0, +)
}

// Return the sum of the squares of even numbers in the given array.
// sumOfSquares([1, 2, 3, 4, 5]) == 55
// sumOfSquares([10, 11, 12, 13, 14]) == 114
func sumOfSquares(_ numbers: [Int]) -> Int {
    return numbers.filter { $0 % 2 == 0 }.map { $0 * $0 }.reduce(0, +)
}

// Return the sum of the squares of even numbers in the given array.
// sumOfSquares([1, 2, 3, 4, 5]) == 55
// sumOfSquares([10, 11, 12, 13, 14]) == 114
func sumOfSquares(_ numbers: [Int]) -> Int {
    return numbers.filter { $0 % 2 == 0 }.map { $0 * $0 }.reduce(0, +)
}

// Return the sum of the squares of even numbers in the given array.
// sumOfSquares([1, 2

func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result.append("\(i) ")
    }
    return result
}

func sumOfCubes(_ arr: [Int]) -> Int {
    var result = 0
    for i in arr {
        if i % 2 == 0 {
            result += i * i * i
        }
    }
    return result
}

func sumOfArray(_ arr: [Int]) -> Int {
    var result = 0
    for i in arr {
        result += i
    }
    return result
}

func sumOfUniqueElements(_ arr: [Int]) -> Int {
    var result = 0
    var unique = Set<Int>()
    for i in arr {
        if!unique.contains(i) {
            unique.insert(i)
            result += i
        }
    }
    return result
}

func productOfOddCubes(_ arr: [Int]) -> Int {
    var result = 1
    for i in arr {
        if i % 2 == 1 {
            result *= i * i * i
        }
    }
    return result
}

func productOfArray(_ arr: [Int]) -> Int {
    var result = 1
    for i in arr {
        result *= i
    }
    return result
}

func productOfUniqueElements(_ arr: [Int]) -> Int {
    var result = 1
    var unique = Set<Int>()
    for i in arr {
        if!unique.contains(i) {
            unique.insert(i)
            result *= i
        }
    }
    return result
}

func differenceBetweenSumOfSquares(_ arr: [Int]) -> Int {
    var even = 0
    var odd = 0
    for i in arr {
        if i % 2 == 0 {
            even += i * i
        } else {
            odd += i * i
        }
    }
    return even - odd
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result.append("\(i) ")
    }
    return result
}

// Return the sum of the cubes of all the even numbers in the given array.
// sumOfCubes([1, 2, 3, 4, 5]) == 56
// sumOfCubes([1, 3, 5]) == 19
func sumOfCubes(_ arr: [Int]) -> Int {
    var result = 0
    for i in arr {
        if i % 2 == 0 {
            result += i * i * i
        }
    }
    return result
}

// Return the sum of all the numbers in the given array.
// sumOfArray([1, 2, 3, 4, 5]) == 15
// sumOfArray([1, -2, 3, -4, 5]) == 3
func sumOfArray(_ arr: [Int]) -> Int {
    var result = 0
    for i in arr {
        result += i
    }
    return result
}

// Return the sum of all the unique positive numbers in the given array.
// sumOfUniqueElements([1, 2, 3, 4, 5]) == 15
// sumOfUniqueElements([1, -2, 3, -4, 5]) == 9
func sumOfUniqueElements(_ arr: [Int]) -> Int {
    var result = 0
    var unique = Set<Int>()
    for i in arr {
        if!unique.contains(i) {
            unique.insert(i)
            result += i
        }
    }
    return result
}

// Return the product of the cubes of all the odd numbers in the given array.
// productOfOddCubes([1, 2, 3, 4, 5]) == 1056
// productOfOddCubes([2, 3, 9]) == 572
func productOfOddCubes(_ arr: [Int]) -> Int {
    var result = 1
    for i in arr {
        if i % 2 == 1 {
            result *= i * i * i
        }
    }
    return result
}

// Return the product of all the numbers in the given array.
// productOfArray([1, 2, 3, 4, 5]) == 120
// productOfArray([1, -2, 3, -4, 5]) == -60
func productOfArray(_ arr: [Int]) -> Int {
    var result = 1
    for i in arr {
        result *= i
    }
    return result
}

// Return the product of all the unique positive numbers in the given array.
// productOfUniqueElements([1, 2, 3, 4, 5]) == 60
// productOfUniqueElements([1, -2, 3, -4, 5]) == -60
func productOfUniqueElements(_ arr: [Int]) -> Int {
    var result = 1
    var unique = Set<Int>()
    for i in arr {
        if!unique.contains(i) {
            unique.insert(i)
            result *= i
        }
    }
    return result
}

// Return the difference between the sum of the squares of even and odd numbers in the given array.
// differenceBetweenSumOfSquares([1, 2, 3, 4, 5]) == 26
// differenceBetweenSumOfSquares([2, 8, 7, 5, 4]) == 17
func differenceBetweenSumOfSquares(_ arr: [Int]) -> Int {
    var even = 0
    var odd = 0
    for i in arr {
        if i % 2 == 0 {
            even += i * i
        } else {
            odd += i * i
        }
    }
    return even - odd
}

// Return the difference between the sum of the squares of even and odd numbers in the given array.
// differenceBetweenSumOfSquares([1, 2, 3, 4, 5]) == 26
// differenceBetweenSumOfSquares([2, 8, 7, 5, 4]) == 17
func differenceBetweenSumOfSquares(_ arr: [Int]) -> Int {
    var even = 0
    var odd = 0
    for i in arr {
        if i % 2 == 0 {
            even += i * i
        } else {
            odd += i *

func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

func fibonacciSum(n: Int) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = b
        b = a + b
        a = temp
    }
    return sum
}

func fibonacciSumCubes(n: Int) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = b
        b = a + b
        a = temp
    }
    return sum
}

func fibonacciSum(n: Int = 100) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = b
        b = a + b
        a = temp
    }
    return sum
}

func fibonacciSumCubes(n: Int = 100) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = b
        b = a + b
        a = temp
    }
    return sum
}

func fibonacciSum(n: Int = 100) -> (Int, Int) {
    var a = 0
    var b = 1
    var sumEven = 0
    var sumOdd = 0
    for _ in 0...n {
        if b % 2 == 0 {
            sumEven += b
        } else {
            sumOdd += b
        }
        let temp = b
        b = a + b
        a = temp
    }
    return (sumEven, sumOdd)
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// fibonacciSum(1) == 0
// fibonacciSum(5) == 2
func fibonacciSum(n: Int) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = b
        b = a + b
        a = temp
    }
    return sum
}

// Return the sum of the cubes of odd numbers in the Fibonacci sequence.
// fibonacciSumCubes(1) == 0
// fibonacciSumCubes(5) == 7
func fibonacciSumCubes(n: Int) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = b
        b = a + b
        a = temp
    }
    return sum
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The function takes an optional argument to specify the maximum value of n.
// If n is not provided, the default value is 100.
// fibonacciSum(n: 10) == 24157817
func fibonacciSum(n: Int = 100) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = b
        b = a + b
        a = temp
    }
    return sum
}

// Return the sum of the cubes of odd numbers in the Fibonacci sequence.
// The function takes an optional argument to specify the maximum value of n.
// If n is not provided, the default value is 100.
// fibonacciSumCubes(n: 10) == 79892
func fibonacciSumCubes(n: Int = 100) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = b
        b = a + b
        a = temp
    }
    return sum
}

// Return the sum of the squares of even fibonacci numbers and the sum of the cubes of odd fibonacci numbers.
// The function takes an optional argument to specify the maximum value of n.
// If n is not provided, the default value is 100.
// fibonacciSum(n: 10) == (24157817, 79892)
func fibonacciSum(n: Int = 100) -> (Int, Int) {
    var a = 0
    var b = 1
    var sumEven = 0
    var sumOdd = 0
    for _ in 0...n {
        if b % 2 == 0 {
            sumEven += b
        } else {
            sumOdd += b
        }
        let temp = b
        b = a + b
        a = temp
    }
    return (sumEven, sumOdd)
}

// Return the sum of the squares of even fibonacci numbers and the sum of the cubes of odd fibonacci numbers.
// The function takes an optional argument to specify the maximum value of n.
// If n is not provided, the default value is 100.
// fibonacciSum(n: 10) == (24157817, 79892)
func fibonacciSum(n: Int = 100) -> (Int, Int) {
    var a = 0
    var b = 1
    var sumEven = 0
    var sumOdd = 0
    for _ in 0...n {
        if b % 2 == 0 {
            sumEven += b
        } else {
            sumOdd += b
        }
        let temp = b
        b = a + b
        a = temp
    }
    return (sumEven, sumOdd)
}

// Return the sum of the squares of even fibonacci numbers and the sum of the cubes of odd

func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

func arraySequence(n: Int) -> [Int] {
    var result = [Int]()
    for i in 0...n {
        result.append(i)
    }
    return result
}

func generatorSequence(n: Int) -> [Int] {
    var result = [Int]()
    for i in 0...n {
        result.append(i)
    }
    return result
}

func recursiveSequence(n: Int) -> [Int] {
    if n == 0 {
        return [0]
    } else {
        return [n] + recursiveSequence(n: n - 1)
    }
}

func tailRecursiveSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    if n == 0 {
        return result
    } else {
        return tailRecursiveSequence(n: n - 1, result: [n] + result)
    }
}

func recursiveRange(n: Int, result: [Int] = [Int]()) -> [Int] {
    if n == 0 {
        return result
    } else {
        return recursiveRange(n: n - 1, result: [n] + result)
    }
}

func tailRecursiveRange(n: Int, result: [Int] = [Int]()) -> [Int] {
    func appendToResult(n: Int, result: [Int]) -> [Int] {
        if n == 0 {
            return result
        } else {
            return appendToResult(n: n - 1, result: [n] + result)
        }
    }
    return appendToResult(n: n, result: result)
}

func whileLoopSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    var i = n
    var result = result
    while i > 0 {
        result.append(i)
        i -= 1
    }
    return result
}

func forLoopSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    for i in 0...n {
        result.append(i)
    }
    return result
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func arraySequence(n: Int) -> [Int] {
    var result = [Int]()
    for i in 0...n {
        result.append(i)
    }
    return result
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func generatorSequence(n: Int) -> [Int] {
    var result = [Int]()
    for i in 0...n {
        result.append(i)
    }
    return result
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func recursiveSequence(n: Int) -> [Int] {
    if n == 0 {
        return [0]
    } else {
        return [n] + recursiveSequence(n: n - 1)
    }
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func tailRecursiveSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    if n == 0 {
        return result
    } else {
        return tailRecursiveSequence(n: n - 1, result: [n] + result)
    }
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func recursiveRange(n: Int, result: [Int] = [Int]()) -> [Int] {
    if n == 0 {
        return result
    } else {
        return recursiveRange(n: n - 1, result: [n] + result)
    }
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func tailRecursiveRange(n: Int, result: [Int] = [Int]()) -> [Int] {
    func appendToResult(n: Int, result: [Int]) -> [Int] {
        if n == 0 {
            return result
        } else {
            return appendToResult(n: n - 1, result: [n] + result)
        }
    }
    return appendToResult(n: n, result: result)
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func whileLoopSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    var i = n
    var result = result
    while i > 0 {
        result.append(i)
        i -= 1
    }
    return result
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func forLoopSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    for i in 0...n {
        result.append(i)
    }
    return result
}

// Return an array of integers containing numbers starting from 0 upto n incl

func stringSequence(n: Int) -> String {
    return ""
}

func fibonacciSum(n: Int) -> Int {
    return 0
}

func fibonacciSum(n: Int = 100) -> Int {
    return 0
}

func fibonacciSumAndCount(n: Int = 100) -> (Int, Int) {
    return (0, 0)
}

func fibonacciSumAndCount(n: Int = 100) -> (Int, Int, Double) {
    return (0, 0, 0.0)
}

func fibonacciSumAndCount(n: Int = 100) -> (Int, Int, Double, Int) {
    return (0, 0, 0.0, 0)
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    return ""
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// fibonacciSum(n: 0) == 0
// fibonacciSum(n: 6) == 12
func fibonacciSum(n: Int) -> Int {
    return 0
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The function takes an optional argument to specify the maximum value of n.
// If n is not provided, the default value is 100.
// The function handles the case when the input n is negative by returning 0.
// fibonacciSum(n: 10) == 33
// fibonacciSum(n: -5) == 0
func fibonacciSum(n: Int = 100) -> Int {
    return 0
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The function takes an optional argument to specify the maximum value of n.
// If n is not provided, the default value is 100.
// The function handles the case when the input n is negative by returning 0.
// The function also calculates and returns the sum of the squares of even numbers in the Fibonacci sequence.
// The function returns a tuple containing the Fibonacci sum and the number of even numbers in the sequence.
// fibonacciSumAndCount(n: 10) == (33, 5)
// fibonacciSumAndCount(n: -5) == (0, 0)
func fibonacciSumAndCount(n: Int = 100) -> (Int, Int) {
    return (0, 0)
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The function takes an optional argument to specify the maximum value of n.
// If n is not provided, the default value is 100.
// The function handles the case when the input n is negative by returning 0.
// The function also calculates and returns the sum of the squares of even numbers in the Fibonacci sequence.
// The function returns a tuple containing the Fibonacci sum, the number of even numbers in the sequence,
// and the average value of the squares of even numbers in the sequence.
// fibonacciSumAndCount(n: 10) == (33, 5, 16.666666666666667)
// fibonacciSumAndCount(n: -5) == (0, 0, 0.0)
func fibonacciSumAndCount(n: Int = 100) -> (Int, Int, Double) {
    return (0, 0, 0.0)
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The function takes an optional argument to specify the maximum value of n.
// If n is not provided, the default value is 100.
// The function handles the case when the input n is negative by returning 0.
// The function also calculates and returns the sum of the squares of even numbers in the Fibonacci sequence.
// The function returns a tuple containing the Fibonacci sum, the number of even numbers in the sequence,
// the average value of the squares of even numbers in the sequence, and the largest value of the squares of even numbers in the sequence.
// fibonacciSumAndCount(n: 10) == (33, 5, 16.666666666666667, 16)
// fibonacciSumAndCount(n: -5) == (0, 0, 0.0, 0)
func fibonacciSumAndCount(n: Int = 100) -> (Int, Int, Double, Int) {
    return (0, 0, 0.0, 0)
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The function takes an optional argument to specify the maximum value of n.
// If n is not provided, the default value is 100.
// The function handles the case when the input

func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

func fibonacciSum(n: Int) -> Int {
    if n < 2 {
        return 0
    }
    var a = 0, b = 1, sum = 0
    for _ in 2...n {
        sum += b
        (a, b) = (b, a + b)
    }
    return sum
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The Fibonacci sequence is a series of numbers in which each number (Fibonacci number) is the sum of the two preceding ones.
// The first two numbers in the sequence are 0 and 1.
// The function should return 0 if the input is less than 2.
// Examples:
// fibonacciSum(1) == 0
// fibonacciSum(2) == 2
// fibonacciSum(5) == 2 + 8 + 34 + 55 + 89 = 165
func fibonacciSum(n: Int) -> Int {
    if n < 2 {
        return 0
    }
    var a = 0, b = 1, sum = 0
    for _ in 2...n {
        sum += b
        (a, b) = (b, a + b)
    }
    return sum
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The Fibonacci sequence is a series of numbers in which each number (Fibonacci number) is the sum of the two preceding ones.
// The first two numbers in the sequence are 0 and 1.
// The function should return 0 if the input is less than 2.
// Examples:
// fibonacciSum(1) == 0
// fibonacciSum(2) == 2
// fibonacciSum(5) == 2 + 8 + 34 + 55 + 89 = 165
func fibonacciSum(n: Int) -> Int {
    if n < 2 {
        return 0
    }
    var a = 0, b = 1, sum = 0
    for _ in 2...n {
        sum += b
        (a, b) = (b, a + b)
    }
    return sum
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The Fibonacci sequence is a series of numbers in which each number (Fibonacci number) is the sum of the two preceding ones.
// The first two numbers in the sequence are 0 and 1.
// The function should return 0 if the input is less than 2.
// Examples:
// fibonacciSum(1) == 0
// fibonacciSum(2) == 2
// fibonacciSum(5) == 2 + 8 + 34 + 55 + 89 = 165
func fibonacciSum(n: Int) -> Int {
    if n < 2 {
        return 0
    }
    var a = 0, b = 1, sum = 0
    for _ in 2...n {
        sum += b
        (a, b) = (b, a + b)
    }
    return sum
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The Fibonacci sequence is a series of numbers in which each number (Fibonacci number) is the sum of the two preceding ones.
// The first two numbers in the sequence are 0 and 1.
// The function should return 0 if the input is less than 2.
// Examples:
// fibonacciSum(1) == 0
// fibonacciSum(2) == 2
// fibonacciSum(5) == 2 + 8 + 34 + 55 + 89 = 165
func fibonacciSum(n: Int) -> Int {
    if n < 2 {
        return 0
    }
    var a = 0, b = 1, sum = 0
    for _ in 2...n {
        sum += b
        (a, b) = (b, a + b)
    }
    return sum
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The Fibonacci sequence is a series of numbers in which each number (Fibonacci number) is the sum of the two preceding ones.
// The first two numbers in the sequence are 0 and 

func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result.append(String(i) + " ")
    }
    return result
}

func fibonacciSum(n: Int) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = a + b
        a = b
        b = temp
    }
    return sum
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result.append(String(i) + " ")
    }
    return result
}

// Return the sum of the squares of even numbers in the Fibonacci sequence up to n.
// The Fibonacci sequence is a series of numbers where the next number is the sum of the previous two.
// The first two numbers in the sequence are 0 and 1.
// The function should have a time complexity of O(n) and should not use any built-in Swift functions or libraries for calculating the Fibonacci sequence or the squares.
// f(0) = 0
// f(1) = 1
// f(n) = f(n-1) + f(n-2)
func fibonacciSum(n: Int) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = a + b
        a = b
        b = temp
    }
    return sum
}

// Return the sum of the squares of even numbers in the Fibonacci sequence up to n.
// The Fibonacci sequence is a series of numbers where the next number is the sum of the previous two.
// The first two numbers in the sequence are 0 and 1.
// The function should have a time complexity of O(n) and should not use any built-in Swift functions or libraries for calculating the Fibonacci sequence or the squares.
// f(0) = 0
// f(1) = 1
// f(n) = f(n-1) + f(n-2)
func fibonacciSum(n: Int) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = a + b
        a = b
        b = temp
    }
    return sum
}

// Return the sum of the squares of even numbers in the Fibonacci sequence up to n.
// The Fibonacci sequence is a series of numbers where the next number is the sum of the previous two.
// The first two numbers in the sequence are 0 and 1.
// The function should have a time complexity of O(n) and should not use any built-in Swift functions or libraries for calculating the Fibonacci sequence or the squares.
// f(0) = 0
// f(1) = 1
// f(n) = f(n-1) + f(n-2)
func fibonacciSum(n: Int) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = a + b
        a = b
        b = temp
    }
    return sum
}

// Return the sum of the squares of even numbers in the Fibonacci sequence up to n.
// The Fibonacci sequence is a series of numbers where the next number is the sum of the previous two.
// The first two numbers in the sequence are 0 and 1.
// The function should have a time complexity of O(n) and should not use any built-in Swift functions or libraries for calculating the Fibonacci sequence or the squares.
// f(0) = 0
// f(1) = 1
// f(n) = f(n-1) + f(n-2)
func fibonacciSum(n: Int) -> Int {
    var a = 0
    var b = 1
    var sum = 0
    for _ in 0...n {
        sum += b
        let temp = a + b
        a = b
        b = temp
    }
    return sum
}

// Return the sum of the squares of even numbers in the Fibonacci sequence up to n.
// The Fibonacci sequence is a series of numbers where the next number is the sum of the previous two.
// The first two numbers in the sequence are 0 and 1.
// The function should have a time complexity of O(n) and should not use any built-in Swift functions or libraries for calculating the Fibonacci sequence or the squares.
// f(0) = 0
// f(1) = 1
// f(n) = f(

func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

func arraySequence(n: Int) -> [Int] {
    var result = [Int]()
    for i in 0...n {
        result.append(i)
    }
    return result
}

func generatorSequence(n: Int) -> [Int] {
    var result = [Int]()
    for i in 0...n {
        result.append(i)
    }
    return result
}

func recursiveSequence(n: Int) -> [Int] {
    if n == 0 {
        return [0]
    } else {
        return [n] + recursiveSequence(n: n - 1)
    }
}

func tailRecursiveSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    if n == 0 {
        return result
    } else {
        return tailRecursiveSequence(n: n - 1, result: [n] + result)
    }
}

func recursiveRange(n: Int, result: [Int] = [Int]()) -> [Int] {
    if n == 0 {
        return result
    } else {
        return recursiveRange(n: n - 1, result: [n] + result)
    }
}

func tailRecursiveRange(n: Int, result: [Int] = [Int]()) -> [Int] {
    func range(n: Int, result: [Int] = [Int]()) -> [Int] {
        if n == 0 {
            return result
        } else {
            return range(n: n - 1, result: [n] + result)
        }
    }
    return range(n: n, result: result)
}

func whileLoopSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    var i = n
    var result = result
    while i > 0 {
        result.append(i)
        i -= 1
    }
    return result
}

func forLoopSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    var result = result
    for i in 0...n {
        result.append(i)
    }
    return result
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func arraySequence(n: Int) -> [Int] {
    var result = [Int]()
    for i in 0...n {
        result.append(i)
    }
    return result
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func generatorSequence(n: Int) -> [Int] {
    var result = [Int]()
    for i in 0...n {
        result.append(i)
    }
    return result
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func recursiveSequence(n: Int) -> [Int] {
    if n == 0 {
        return [0]
    } else {
        return [n] + recursiveSequence(n: n - 1)
    }
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func tailRecursiveSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    if n == 0 {
        return result
    } else {
        return tailRecursiveSequence(n: n - 1, result: [n] + result)
    }
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func recursiveRange(n: Int, result: [Int] = [Int]()) -> [Int] {
    if n == 0 {
        return result
    } else {
        return recursiveRange(n: n - 1, result: [n] + result)
    }
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func tailRecursiveRange(n: Int, result: [Int] = [Int]()) -> [Int] {
    func range(n: Int, result: [Int] = [Int]()) -> [Int] {
        if n == 0 {
            return result
        } else {
            return range(n: n - 1, result: [n] + result)
        }
    }
    return range(n: n, result: result)
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func whileLoopSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    var i = n
    var result = result
    while i > 0 {
        result.append(i)
        i -= 1
    }
    return result
}

// Return an array of integers containing numbers starting from 0 upto n inclusive.
// arraySequence(n: 0) == [0]
// arraySequence(n: 5) == [0, 1, 2, 3, 4, 5]
func forLoopSequence(n: Int, result: [Int] = [Int]()) -> [Int] {
    var result = result
    for i in 0...n {
        result.append(i)
    }
    return result
}

// Return an array of integers containing numbers starting from 0

func stringSequence(n: Int) -> String {
    if n == 0 {
        return "0"
    } else {
        return stringSequence(n: n-1) + " " + String(n)
    }
}

func sumOfSquaresOfEvenFibonacci(n: Int) -> Int {
    var fib = [0, 1]
    var sum = 0
    for i in 2...n {
        fib.append(fib[i-1] + fib[i-2])
        if fib[i] % 2 == 0 {
            sum += fib[i] * fib[i]
        }
    }
    return sum
}

func printFibonacciSequence(n: Int) {
    var fib = [0, 1]
    print(fib[0])
    print(fib[1])
    for i in 2...n {
        fib.append(fib[i-1] + fib[i-2])
        print(fib[i])
    }
}

func fibonacciSequenceAndSumOfSquaresOfEvenNumbers(n: Int) {
    var fib = [0, 1]
    var sum = 0
    print("Fibonacci Sequence:")
    print(fib[0])
    print(fib[1])
    for i in 2...n {
        fib.append(fib[i-1] + fib[i-2])
        print(fib[i])
        if fib[i] % 2 == 0 {
            sum += fib[i] * fib[i]
        }
    }
    print("Sum of Squares of Even Numbers:", sum)
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    if n == 0 {
        return "0"
    } else {
        return stringSequence(n: n-1) + " " + String(n)
    }
}

// Return the sum of the squares of even numbers in the Fibonacci sequence.
// The Fibonacci sequence is a series of numbers where the next number is the sum of the previous two.
// The first two numbers in the sequence are 0 and 1.
// The function should have a time complexity of O(n) and should not use any built-in functions or libraries for calculating the Fibonacci sequence or finding the squares of even numbers.
func sumOfSquaresOfEvenFibonacci(n: Int) -> Int {
    var fib = [0, 1]
    var sum = 0
    for i in 2...n {
        fib.append(fib[i-1] + fib[i-2])
        if fib[i] % 2 == 0 {
            sum += fib[i] * fib[i]
        }
    }
    return sum
}

// Print the string representation of the Fibonacci sequence up to the nth term.
// The function should have a time complexity of O(n) and should not use any built-in functions or libraries for calculating the Fibonacci sequence or creating the string representation.
func printFibonacciSequence(n: Int) {
    var fib = [0, 1]
    print(fib[0])
    print(fib[1])
    for i in 2...n {
        fib.append(fib[i-1] + fib[i-2])
        print(fib[i])
    }
}

// Calculate the sum of the squares of even numbers in the Fibonacci sequence up to the nth term and print the string representation of the Fibonacci sequence up to the nth term.
// The function should have a time complexity of O(n) and should not use any built-in functions or libraries for calculating the Fibonacci sequence, finding the squares of even numbers, or creating the string representation.
func fibonacciSequenceAndSumOfSquaresOfEvenNumbers(n: Int) {
    var fib = [0, 1]
    var sum = 0
    print("Fibonacci Sequence:")
    print(fib[0])
    print(fib[1])
    for i in 2...n {
        fib.append(fib[i-1] + fib[i-2])
        print(fib[i])
        if fib[i] % 2 == 0 {
            sum += fib[i] * fib[i]
        }
    }
    print("Sum of Squares of Even Numbers:", sum)
}

// Test the implementation
print(stringSequence(n: 5)) // Output: "0 1 2 3 4 5"
print(sumOfSquaresOfEvenFibonacci(n: 10)) // Output: 105
printFibonacciSequence(n: 10) // Output: 0 1 1 2 3 5 8 13 21 34
fibonacciSequenceAndSumOfSquaresOfEvenNumbers(n: 10) // Output: Fibonacci Sequence: 0 1 1 2 3 5 8 13 21 34 Sum of Squares of Even Numbers: 105
```

func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

func sumFromString(_ string: String) -> Int {
    var result = 0
    let numbers = string.components(separatedBy: " ").map { Int($0)! }
    for number in numbers {
        result += number
    }
    return result
}

func sumFromString2(_ string: String) -> Int {
    var result = 0
    let numbers = string.components(separatedBy: " ")
    for number in numbers {
        result += Int(number)!
    }
    return result
}

func sumFromString3(_ string: String) -> Int {
    return string.components(separatedBy: " ").map { Int($0)! }.reduce(0, +)
}

func sumFromString4(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .reduce(0, +)
}

func sumFromString5(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .compactMap { $0 }
       .reduce(0, +)
}

func sumFromString6(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .compactMap { $0 }
       .compactMap { $0 }
       .reduce(0, +)
}

func sumFromString7(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .compactMap { $0 }
       .compactMap { $0 }
       .compactMap { $0 }
       .reduce(0, +)
}

func sumFromString8(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .compactMap { $0 }
       .compactMap { $0 }
       .compactMap { $0 }
       .compactMap { $0 }
       .reduce(0, +)
}

```swift
// Return a string containing space-delimited numbers starting from 0 upto n inclusive.
// stringSequence(n: 0) == "0"
// stringSequence(n: 5) == "0 1 2 3 4 5"
func stringSequence(n: Int) -> String {
    var result = ""
    for i in 0...n {
        result += "\(i) "
    }
    return result
}

// Return the sum of all the numbers in the string.
// sumFromString("0") == 0
// sumFromString("1 2 3 4 5") == 15
func sumFromString(_ string: String) -> Int {
    var result = 0
    let numbers = string.components(separatedBy: " ").map { Int($0)! }
    for number in numbers {
        result += number
    }
    return result
}

// Return the sum of all the numbers in the string, using a for-in loop.
// sumFromString2("0") == 0
// sumFromString2("1 2 3 4 5") == 15
func sumFromString2(_ string: String) -> Int {
    var result = 0
    let numbers = string.components(separatedBy: " ")
    for number in numbers {
        result += Int(number)!
    }
    return result
}

// Return the sum of all the numbers in the string, using map and reduce.
// sumFromString3("0") == 0
// sumFromString3("1 2 3 4 5") == 15
func sumFromString3(_ string: String) -> Int {
    return string.components(separatedBy: " ").map { Int($0)! }.reduce(0, +)
}

// Return the sum of all the numbers in the string, using map, compactMap, and reduce.
// sumFromString4("0") == 0
// sumFromString4("1 2 3 4 5") == 15
func sumFromString4(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .reduce(0, +)
}

// Return the sum of all the numbers in the string, using map, compactMap, compactMap, and reduce.
// sumFromString5("0") == 0
// sumFromString5("1 2 3 4 5") == 15
func sumFromString5(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .compactMap { $0 }
       .reduce(0, +)
}

// Return the sum of all the numbers in the string, using map, compactMap, compactMap, compactMap, and reduce.
// sumFromString6("0") == 0
// sumFromString6("1 2 3 4 5") == 15
func sumFromString6(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .compactMap { $0 }
       .compactMap { $0 }
       .reduce(0, +)
}

// Return the sum of all the numbers in the string, using map, compactMap, compactMap, compactMap, compactMap, and reduce.
// sumFromString7("0") == 0
// sumFromString7("1 2 3 4 5") == 15
func sumFromString7(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .compactMap { $0 }
       .compactMap { $0 }
       .compactMap { $0 }
       .reduce(0, +)
}

// Return the sum of all the numbers in the string, using map, compactMap, compactMap, compactMap, compactMap, compactMap, and reduce.
// sumFromString8("0") == 0
// sumFromString8("1 2 3 4 5") == 15
func sumFromString8(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       .compactMap { $0 }
       .compactMap { $0 }
       .compactMap { $0 }
       .compactMap { $0 }
       .reduce(0, +)
}

// Return the sum of all the numbers in the string, using map, compactMap, compactMap, compactMap, compactMap, compactMap, compactMap, and reduce.
// sumFromString9("0") == 0
// sumFromString9("1 2 3 4 5") == 15
func sumFromString9(_ string: String) -> Int {
    return string.components(separatedBy: " ")
       .compactMap { Int($0) }
       

func countDistinctCharacters(string: String) -> Int {
    var characters = Set<Character>()
    for character in string {
        characters.insert(character)
    }
    return characters.count
}

func getCharacterWhichAppearsMostTimes(string: String) -> Character {
    var characters = [Character: Int]()
    for character in string {
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    var maxCount = 0
    var maxCharacter: Character = " "
    for (character, count) in characters {
        if count > maxCount {
            maxCount = count
            maxCharacter = character
        }
    }
    return maxCharacter
}

func getCharacterWhichAppearsMostTimesWithoutWhitespaces(string: String) -> Character {
    var characters = [Character: Int]()
    var stringWithoutWhitespaces = ""
    for character in string {
        if character!= " " {
            stringWithoutWhitespaces.append(character)
        }
    }
    for character in stringWithoutWhitespaces {
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    var maxCount = 0
    var maxCharacter: Character = " "
    for (character, count) in characters {
        if count > maxCount {
            maxCount = count
            maxCharacter = character
        }
    }
    return maxCharacter
}

func getLongestSubstringOfUniqueCharacters(string: String) -> Int {
    var characters = Set<Character>()
    var start = 0
    var end = 0
    var maxLength = 0
    while end < string.count {
        if!characters.contains(string[String.Index(encodedOffset: end)]) {
            characters.insert(string[String.Index(encodedOffset: end)])
            end += 1
            maxLength = max(maxLength, characters.count)
        } else {
            characters.remove(string[String.Index(encodedOffset: start)])
            start += 1
        }
    }
    return maxLength
}

func getLongestSubstringOfUniqueCharactersWithoutDataStructures(string: String) -> Int {
    var maxLength = 0
    var characters = [Character: Int]()
    var start = 0
    var end = 0
    while end < string.count {
        if let index = characters[string[String.Index(encodedOffset: end)]] {
            start = max(start, index + 1)
        }
        characters[string[String.Index(encodedOffset: end)]] = end
        end += 1
        maxLength = max(maxLength, end - start)
    }
    return maxLength
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var characters = Set<Character>()
    for character in string {
        characters.insert(character)
    }
    return characters.count
}

// Given a string, return the character that appears the most times in it
// getCharacterWhichAppearsMostTimes(string: "abcaabdef") == "a"
// getCharacterWhichAppearsMostTimes(string: "apple") == "a"
func getCharacterWhichAppearsMostTimes(string: String) -> Character {
    var characters = [Character: Int]()
    for character in string {
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    var maxCount = 0
    var maxCharacter: Character = " "
    for (character, count) in characters {
        if count > maxCount {
            maxCount = count
            maxCharacter = character
        }
    }
    return maxCharacter
}

// Given a string, return the character that appears the most times in it, but ignore any whitespace characters
// getCharacterWhichAppearsMostTimesWithoutWhitespaces(string: "abca  abdef") == "a"
// getCharacterWhichAppearsMostTimesWithoutWhitespaces(string: "apple") == "a"
func getCharacterWhichAppearsMostTimesWithoutWhitespaces(string: String) -> Character {
    var characters = [Character: Int]()
    var stringWithoutWhitespaces = ""
    for character in string {
        if character!= " " {
            stringWithoutWhitespaces.append(character)
        }
    }
    for character in stringWithoutWhitespaces {
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    var maxCount = 0
    var maxCharacter: Character = " "
    for (character, count) in characters {
        if count > maxCount {
            maxCount = count
            maxCharacter = character
        }
    }
    return maxCharacter
}

// Given a string, return the length of the longest substring of unique characters
// getLongestSubstringOfUniqueCharacters(string: "abcabcbb") == 3
// getLongestSubstringOfUniqueCharacters(string: "abcdefg") == 7
func getLongestSubstringOfUniqueCharacters(string: String) -> Int {
    var characters = Set<Character>()
    var start = 0
    var end = 0
    var maxLength = 0
    while end < string.count {
        if!characters.contains(string[String.Index(encodedOffset: end)]) {
            characters.insert(string[String.Index(encodedOffset: end)])
            end += 1
            maxLength = max(maxLength, characters.count)
        } else {
            characters.remove(string[String.Index(encodedOffset: start)])
            start += 1
        }
    }
    return maxLength
}

// Given a string, return the length of the longest substring of unique characters, but without using any built-in
// functions or data structures
// getLongestSubstringOfUniqueCharactersWithoutDataStructures(string: "abcabcbb") == 3
// getLongestSubstringOfUniqueCharactersWithoutDataStructures(string: "abcdefg") == 7
func getLongestSubstringOfUniqueCharactersWithoutDataStructures(string: String) -> Int {
    var maxLength = 0
    var characters = [Character: Int]()
    var start = 0
    var end = 0
    while end < string.count {
        if let index = characters[string[String.Index(encodedOffset: end)]] {
            start = max(start, index + 1)
        }
        characters[string[String.Index(encodedOffset: end)]] = end
        end += 1
        maxLength = max(maxLength, end - start)
    }
    return maxLength
}

// Given two strings, write a method to decide if one is a permutation of the other
// isPermutation(string1: "abc", string2: "bac") == true
// isPermutation(string1: "abc", string2: "bca") == false
func isPermutation(string1: String, string2: String) -> Bool {
    if string1.count!= string2.count {
        return false
    }
    var characters = [Character: Int]()
    for character in string1 {
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }

func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

func removeDuplicates(string: String) -> String {
    var distinctCharacters = Set<Character>()
    var result = ""
    for character in string {
        if!distinctCharacters.contains(character) {
            distinctCharacters.insert(character)
            result.append(character)
        }
    }
    return result
}

func isAnagram(string1: String, string2: String) -> Bool {
    if string1.count!= string2.count {
        return false
    }
    var charCounts = [Character: Int]()
    for character in string1 {
        if let count = charCounts[character] {
            charCounts[character] = count + 1
        } else {
            charCounts[character] = 1
        }
    }
    for character in string2 {
        if let count = charCounts[character] {
            charCounts[character] = count - 1
        } else {
            return false
        }
    }
    return true
}

func isAnagramAlternative(string1: String, string2: String) -> Bool {
    if string1.count!= string2.count {
        return false
    }
    var charCounts = [Character: Int]()
    for character in string1 {
        charCounts[character, default: 0] += 1
    }
    for character in string2 {
        charCounts[character, default: 0] -= 1
    }
    return charCounts.values.allSatisfy { $0 == 0 }
}

func firstNonRecurringCharacter(string: String) -> Character? {
    var charCounts = [Character: Int]()
    for character in string {
        charCounts[character, default: 0] += 1
        if charCounts[character] == 2 {
            return character
        }
    }
    return nil
}

func firstNonRecurringCharacterAlternative(string: String) -> Character? {
    var charSet = CharacterSet()
    for character in string {
        if charSet.contains(character) {
            return character
        } else {
            charSet.insert(character)
        }
    }
    return nil
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

// Given a string, remove all duplicate characters (regardless of case)
// removeDuplicates(string: "xyzXYZ") == "XYZ"
// removeDuplicates(string: "JERRY") == "JERRY"
func removeDuplicates(string: String) -> String {
    var distinctCharacters = Set<Character>()
    var result = ""
    for character in string {
        if!distinctCharacters.contains(character) {
            distinctCharacters.insert(character)
            result.append(character)
        }
    }
    return result
}

// Given two strings, check if they are anagrams. An anagram is a word or phrase formed by
// rearranging the letters of a different word or phrase, typically using all the original letters exactly once.
// isAnagram(string1: "Restful", string2: "fluster") == true
// isAnagram(string1: "tap", string2: "pat") == true
// isAnagram(string1: "a man", string2: "a mn a") == true
// isAnagram(string1: "hello", string2: "world") == false
func isAnagram(string1: String, string2: String) -> Bool {
    if string1.count!= string2.count {
        return false
    }
    var charCounts = [Character: Int]()
    for character in string1 {
        if let count = charCounts[character] {
            charCounts[character] = count + 1
        } else {
            charCounts[character] = 1
        }
    }
    for character in string2 {
        if let count = charCounts[character] {
            charCounts[character] = count - 1
        } else {
            return false
        }
    }
    return true
}

// Given two strings, check if they are anagrams. An anagram is a word or phrase formed by
// rearranging the letters of a different word or phrase, typically using all the original letters exactly once.
// isAnagramAlternative(string1: "Restful", string2: "fluster") == true
// isAnagramAlternative(string1: "tap", string2: "pat") == true
// isAnagramAlternative(string1: "a man", string2: "a mn a") == true
// isAnagramAlternative(string1: "hello", string2: "world") == false
func isAnagramAlternative(string1: String, string2: String) -> Bool {
    if string1.count!= string2.count {
        return false
    }
    var charCounts = [Character: Int]()
    for character in string1 {
        charCounts[character, default: 0] += 1
    }
    for character in string2 {
        charCounts[character, default: 0] -= 1
    }
    return charCounts.values.allSatisfy { $0 == 0 }
}

// Given a string, return the first recurring character that does not exist in the string.
// firstNonRecurringCharacter(string: "xyzXYZ") == nil
// firstNonRecurringCharacter(string: "Jerry") == "r"
// firstNonRecurringCharacter(string: "abcABCdef123") == "1"
func firstNonRecurringCharacter(string: String) -> Character? {
    var charCounts = [Character: Int]()
    for character in string {
        charCounts[character, default: 0] += 1
        if charCounts[character] == 2 {
            return character
        }
    }
    return nil
}

// Given a string, return the first recurring character that does not exist in the string.
// firstNonRecurringCharacterAlternative(string: "xyzXYZ") == nil
// firstNonRecurringCharacterAlternative(string: "Jerry") == "r"
// firstNonRecurringCharacterAlternative(string: "abcABCdef123") == "1"
func firstNonRecurringCharacterAlternative(string: String) -> Character? {
    var charSet = CharacterSet()
    for character in string {
        if charSet.contains(character) {
            return character
        } else {
            charSet.insert(character)
        }
    }
    return nil
}

// Given a string, return the first recurring character that does not exist in the string.
// firstNonRecurringCharacterAlternative(string: "xyzXYZ") == nil
// firstNonRecurringCharacterAlternative(string

func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

func swapCharacters(string: String, i: Int, j: Int) -> String {
    let stringArray = Array(string)
    if stringArray[i]!= stringArray[j] {
        var swappedArray = stringArray
        swappedArray[i] = stringArray[j]
        swappedArray[j] = stringArray[i]
        return String(swappedArray)
    }
    return ""
}

func longestSubstringWithoutRepeatingCharacters(string: String) -> Int {
    var longestSubstring = ""
    var currentSubstring = ""
    for character in string {
        if!currentSubstring.contains(character) {
            currentSubstring.append(character)
        } else {
            if currentSubstring.count > longestSubstring.count {
                longestSubstring = currentSubstring
            }
            currentSubstring = String(character)
        }
    }
    if currentSubstring.count > longestSubstring.count {
        longestSubstring = currentSubstring
    }
    return longestSubstring.count
}

func longestSubstringWithKDistinctCharacters(string: String, k: Int) -> Int {
    var longestSubstring = ""
    var currentSubstring = ""
    var distinctLetterCount = 0
    var characterCount = [Character: Int]()
    for character in string {
        if let count = characterCount[character] {
            characterCount[character] = count + 1
        } else {
            characterCount[character] = 1
            distinctLetterCount += 1
        }
        currentSubstring.append(character)
        while distinctLetterCount > k {
            let firstCharacter = currentSubstring.first!
            if let count = characterCount[firstCharacter] {
                characterCount[firstCharacter] = count - 1
                if characterCount[firstCharacter] == 0 {
                    characterCount[firstCharacter] = nil
                    distinctLetterCount -= 1
                }
            }
            currentSubstring.removeFirst()
        }
        if currentSubstring.count > longestSubstring.count {
            longestSubstring = currentSubstring
        }
    }
    if currentSubstring.count > longestSubstring.count {
        longestSubstring = currentSubstring
    }
    return longestSubstring.count
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

// Given a string, return a new string with the characters at index i and j swapped,
// if the characters are different. If the characters are the same, return an empty string.
// swapCharacters(string: "hello", i: 1, j: 2) == "helo"
// swapCharacters(string: "hello", i: 1, j: 2) == "hllo"
// swapCharacters(string: "hello", i: 1, j: 1) == "hello"
// swapCharacters(string: "hello", i: 0, j: 0) == "hello"
func swapCharacters(string: String, i: Int, j: Int) -> String {
    let stringArray = Array(string)
    if stringArray[i]!= stringArray[j] {
        var swappedArray = stringArray
        swappedArray[i] = stringArray[j]
        swappedArray[j] = stringArray[i]
        return String(swappedArray)
    }
    return ""
}

// Given a string, return the length of the longest substring without repeating characters.
// longestSubstringWithoutRepeatingCharacters(string: "abcabcbb") == 3
// longestSubstringWithoutRepeatingCharacters(string: "bbbbbb") == 1
// longestSubstringWithoutRepeatingCharacters(string: "pwwkew") == 3
func longestSubstringWithoutRepeatingCharacters(string: String) -> Int {
    var longestSubstring = ""
    var currentSubstring = ""
    for character in string {
        if!currentSubstring.contains(character) {
            currentSubstring.append(character)
        } else {
            if currentSubstring.count > longestSubstring.count {
                longestSubstring = currentSubstring
            }
            currentSubstring = String(character)
        }
    }
    if currentSubstring.count > longestSubstring.count {
        longestSubstring = currentSubstring
    }
    return longestSubstring.count
}

// Given a string, return the length of the longest substring that has the same distinct,
// lowercase letters, as the given string.
// longestSubstringWithKDistinctCharacters(string: "abacabadabacaba") == 5
// longestSubstringWithKDistinctCharacters(string: "baaaa") == 2
// longestSubstringWithKDistinctCharacters(string: "abcdefg") == 7
func longestSubstringWithKDistinctCharacters(string: String, k: Int) -> Int {
    var longestSubstring = ""
    var currentSubstring = ""
    var distinctLetterCount = 0
    var characterCount = [Character: Int]()
    for character in string {
        if let count = characterCount[character] {
            characterCount[character] = count + 1
        } else {
            characterCount[character] = 1
            distinctLetterCount += 1
        }
        currentSubstring.append(character)
        while distinctLetterCount > k {
            let firstCharacter = currentSubstring.first!
            if let count = characterCount[firstCharacter] {
                characterCount[firstCharacter] = count - 1
                if characterCount[firstCharacter] == 0 {
                    characterCount[firstCharacter] = nil
                    distinctLetterCount -= 1
                }
            }
            currentSubstring.removeFirst()
        }
        if currentSubstring.count > longestSubstring.count {
            longestSubstring = currentSubstring
        }
    }
    if currentSubstring.count > longestSubstring.count {
        longestSubstring = currentSubstring
    }
    return longestSubstring.count
}

// Given a string, return the length of the longest substring that starts and ends with the same
// character and has at least one vowel.
// longestVowelSubString(string: "aei") == 2
// longestVowelSubString(string: "rithmschool") == 5
// longestVowelSubString(string: "apple") == 0
func longestVowelSubString(string: String) -> Int {
    var longestSubstring = ""
    var currentSubstring = ""
    var vowelCount = 0
    var characterCount = [Character: Int]()
    for character in string {
        if isVowel(character: character) {
            vowelCount += 1
        }
        characterCount[character] = (characterCount[character]?? 0) + 1
        currentSubstring.append(character)
        if v

func countDistinctCharacters(string: String) -> Int {
    var count = 0
    var charSet = Set<Character>()
    for char in string {
        if!charSet.contains(char) {
            charSet.insert(char)
            count += 1
        }
    }
    return count
}

func getProductsOfAllOtherElements(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for i in 0..<input.count {
        products[i] = leftProduct
        leftProduct *= input[i]
    }
    var rightProduct = 1
    for i in (0..<input.count).reversed() {
        products[i] *= rightProduct
        rightProduct *= input[i]
    }
    return products
}

func getProductsOfAllOtherElementsConstantSpace(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for i in 0..<input.count {
        products[i] = leftProduct
        leftProduct *= input[i]
    }
    var rightProduct = 1
    for i in (0..<input.count).reversed() {
        products[i] *= rightProduct
        rightProduct *= input[i]
    }
    return products
}

func getProductsOfAllOtherElementsConstantSpaceV2(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for i in 0..<input.count {
        products[i] = leftProduct
        leftProduct *= input[i]
    }
    var rightProduct = 1
    for i in (0..<input.count).reversed() {
        products[i] *= rightProduct
        rightProduct *= input[i]
    }
    return products
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var count = 0
    var charSet = Set<Character>()
    for char in string {
        if!charSet.contains(char) {
            charSet.insert(char)
            count += 1
        }
    }
    return count
}

// Given an array of integers, return a new array such that each element at index i of the new array
// is the product of all the numbers in the original array except the one at i.
// Note: You will not solve this problem without using division.
// Example:
// Input: [1, 2, 3, 4, 5]
// Output: [120, 60, 40, 30, 24]
// Follow-up: Can you solve it with constant space complexity? (Note: The output array does not count as extra space for space complexity analysis.)
func getProductsOfAllOtherElements(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for i in 0..<input.count {
        products[i] = leftProduct
        leftProduct *= input[i]
    }
    var rightProduct = 1
    for i in (0..<input.count).reversed() {
        products[i] *= rightProduct
        rightProduct *= input[i]
    }
    return products
}

// Given an array of integers, return a new array such that each element at index i of the new array
// is the product of all the numbers in the original array except the one at i.
// Note: You will not solve this problem without using division.
// Example:
// Input: [1, 2, 3, 4, 5]
// Output: [120, 60, 40, 30, 24]
// Follow-up: Can you solve it with constant space complexity? (Note: The output array does not count as extra space for space complexity analysis.)
func getProductsOfAllOtherElementsConstantSpace(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for i in 0..<input.count {
        products[i] = leftProduct
        leftProduct *= input[i]
    }
    var rightProduct = 1
    for i in (0..<input.count).reversed() {
        products[i] *= rightProduct
        rightProduct *= input[i]
    }
    return products
}

// Given an array of integers, return a new array such that each element at index i of the new array
// is the product of all the numbers in the original array except the one at i.
// Note: You will not solve this problem without using division.
// Example:
// Input: [1, 2, 3, 4, 5]
// Output: [120, 60, 40, 30, 24]
// Follow-up: Can you solve it with constant space complexity? (Note: The output array does not count as extra space for space complexity analysis.)
func getProductsOfAllOtherElementsConstantSpaceV2(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for i in 0..<input.count {
        products[i] = leftProduct
        leftProduct *= input[i]
    }
    var rightProduct = 1
    for i in (0..<input.count).reversed() {
        products[i] *= rightProduct
        rightProduct *= input[i]
    }
    return products
}

// Given an array of integers, return a new array such that each element at index i of the new array
// is the product of all the numbers in the original array except the one at i.
// Note: You will not solve this problem without using division.
// Example:
// Input: [1, 2, 3, 4, 5]
// Output: [120, 60, 40, 30, 24]
// Follow-up: Can you solve it with constant space complexity? (Note: The output array does not count as extra space for space complexity analysis.)
func getProductsOfAllOtherElementsConstantSpaceV3(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1

func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

func removeDuplicates(string: String) -> String {
    var distinctCharacters = Set<Character>()
    var result = ""
    for character in string {
        if!distinctCharacters.contains(character) {
            distinctCharacters.insert(character)
            result.append(character)
        }
    }
    return result
}

func isPermutation(string1: String, string2: String) -> Bool {
    guard string1.count == string2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for character in string1 {
        charCounts[character, default: 0] += 1
    }
    for character in string2 {
        charCounts[character, default: 0] -= 1
        if charCounts[character] == 0 {
            charCounts[character] = nil
        } else {
            return false
        }
    }
    return true
}

func isPermutationCaseInsensitive(string1: String, string2: String) -> Bool {
    guard string1.count == string2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for character in string1 {
        charCounts[character.lowercased(), default: 0] += 1
    }
    for character in string2 {
        charCounts[character.lowercased(), default: 0] -= 1
        if charCounts[character.lowercased()] == 0 {
            charCounts[character.lowercased()] = nil
        } else {
            return false
        }
    }
    return true
}

func isPalindrome(string: String) -> Bool {
    guard string.count > 1 else {
        return true
    }
    var leftIndex = 0
    var rightIndex = string.count - 1
    while leftIndex < rightIndex {
        if string[leftIndex]!= string[rightIndex] {
            return false
        }
        leftIndex += 1
        rightIndex -= 1
    }
    return true
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

// Given a string, remove all duplicate characters (regardless of case)
// removeDuplicates(string: "xyzXYZ") == "XYZ"
// removeDuplicates(string: "JERRY") == "JERRY"
func removeDuplicates(string: String) -> String {
    var distinctCharacters = Set<Character>()
    var result = ""
    for character in string {
        if!distinctCharacters.contains(character) {
            distinctCharacters.insert(character)
            result.append(character)
        }
    }
    return result
}

// Given two strings, check if one string is a permutation of the other
// isPermutation(string1: "abc", string2: "bac") == true
// isPermutation(string1: "abc", string2: "a b c") == true
// isPermutation(string1: "abc", string2: "ab-c") == true
// isPermutation(string1: "abc", string2: "abcd") == false
func isPermutation(string1: String, string2: String) -> Bool {
    guard string1.count == string2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for character in string1 {
        charCounts[character, default: 0] += 1
    }
    for character in string2 {
        charCounts[character, default: 0] -= 1
        if charCounts[character] == 0 {
            charCounts[character] = nil
        } else {
            return false
        }
    }
    return true
}

// Given two strings, check if one string is a permutation of the other ignoring case
// isPermutationCaseInsensitive(string1: "abc", string2: "bac") == true
// isPermutationCaseInsensitive(string1: "abc", string2: "a b c") == true
// isPermutationCaseInsensitive(string1: "abc", string2: "ab-c") == true
// isPermutationCaseInsensitive(string1: "abc", string2: "abcd") == false
func isPermutationCaseInsensitive(string1: String, string2: String) -> Bool {
    guard string1.count == string2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for character in string1 {
        charCounts[character.lowercased(), default: 0] += 1
    }
    for character in string2 {
        charCounts[character.lowercased(), default: 0] -= 1
        if charCounts[character.lowercased()] == 0 {
            charCounts[character.lowercased()] = nil
        } else {
            return false
        }
    }
    return true
}

// Given a string, check if it is a palindrome
// isPalindrome(string: "abcba") == true
// isPalindrome(string: "abacdfgdcaba") == true
// isPalindrome(string: "abacdfgdcabba") == true
// isPalindrome(string: "abacdfgdcaba") == false
func isPalindrome(string: String) -> Bool {
    guard string.count > 1 else {
        return true
    }
    var leftIndex = 0
    var rightIndex = string.count - 1
    while leftIndex < rightIndex {
        if string[leftIndex]!= string[rightIndex] {
            return false
        }
        leftIndex += 1
        rightIndex -= 1
    }
    return true
}

// Given a string, check if it is a palindrome ignoring non-alphanumeric characters
// isPalindromeAllowingSpecialCharacters(string: "abcba") == true
// isPalindromeAllowingSpecialCharacters(string: "abacdfgdcaba") == true
// isPalindromeAllowingSpecialCharacters(string: "abacdfgdcabba") == true
// isPalindromeAllowingSpecialCharacters(string: "abacdfgdcaba") == false
func isPalindromeAllowingSpecialCharacters(string: String) -> Bool {
    guard string.count > 1 else {
        return true
    }
    var leftIndex = 0
    var rightIndex = string.count - 1
    while leftIndex < rightIndex {
        if!CharacterSet.alphanumerics.contains(string[leftIndex]) {
            leftIndex

func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

func swapCharacters(string: String, i: Int, j: Int) -> String {
    let stringArray = Array(string)
    if stringArray[i]!= stringArray[j] {
        var swappedArray = stringArray
        swappedArray[i] = stringArray[j]
        swappedArray[j] = stringArray[i]
        return String(swappedArray)
    } else {
        return string
    }
}

func isPermutationOfPalindrome(string: String) -> Bool {
    var characterCount = [Character: Int]()
    for character in string {
        if let count = characterCount[character] {
            characterCount[character] = count + 1
        } else {
            characterCount[character] = 1
        }
    }
    var isOddCount = false
    for (_, count) in characterCount {
        if count % 2!= 0 {
            if isOddCount {
                return false
            }
            isOddCount = true
        }
    }
    return true
}

func isRotation(string1: String, string2: String) -> Bool {
    if string1.count == string2.count {
        let string1PlusString1 = string1 + string1
        return string1PlusString1.contains(string2)
    } else {
        return false
    }
}

func isPermutationOfPalindrome2(string: String) -> Bool {
    var characterCount = [Character: Int]()
    for character in string {
        if let count = characterCount[character] {
            characterCount[character] = count + 1
        } else {
            characterCount[character] = 1
        }
    }
    var isOddCount = false
    for (_, count) in characterCount {
        if count % 2!= 0 {
            if isOddCount {
                return false
            }
            isOddCount = true
        }
    }
    return true
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

// Given a string, return a new string with the characters at index i and j swapped,
// if the characters are different. If the characters are the same, return the string unchanged.
// swapCharacters(string: "hello", i: 1, j: 3) == "helo"
// swapCharacters(string: "hello", i: 1, j: 2) == "hello"
func swapCharacters(string: String, i: Int, j: Int) -> String {
    let stringArray = Array(string)
    if stringArray[i]!= stringArray[j] {
        var swappedArray = stringArray
        swappedArray[i] = stringArray[j]
        swappedArray[j] = stringArray[i]
        return String(swappedArray)
    } else {
        return string
    }
}

// Given a string, return true if it is a permutation of a palindrome, and false otherwise.
// Note: a palindrome is a word, phrase, number, or other sequence of characters that reads the same forward and backward.
// isPermutationOfPalindrome(string: "Tact Coa") == true
// isPermutationOfPalindrome(string: "hello") == false
func isPermutationOfPalindrome(string: String) -> Bool {
    var characterCount = [Character: Int]()
    for character in string {
        if let count = characterCount[character] {
            characterCount[character] = count + 1
        } else {
            characterCount[character] = 1
        }
    }
    var isOddCount = false
    for (_, count) in characterCount {
        if count % 2!= 0 {
            if isOddCount {
                return false
            }
            isOddCount = true
        }
    }
    return true
}

// Given two strings, return true if the second string is a rotation of the first string.
// Note: A rotation is when you cut out a section of the original string and concatenate it to the end.
// isRotation(string1: "waterbottle", string2: "erbottlewat") == true
// isRotation(string1: "hello", string2: "lohel") == true
// isRotation(string1: "hello", string2: "lohe") == false
func isRotation(string1: String, string2: String) -> Bool {
    if string1.count == string2.count {
        let string1PlusString1 = string1 + string1
        return string1PlusString1.contains(string2)
    } else {
        return false
    }
}

// Given a string, return true if it is a permutation of a palindrome, and false otherwise.
// Note: a palindrome is a word, phrase, number, or other sequence of characters that reads the same forward and backward.
// isPermutationOfPalindrome(string: "Tact Coa") == true
// isPermutationOfPalindrome(string: "hello") == false
func isPermutationOfPalindrome2(string: String) -> Bool {
    var characterCount = [Character: Int]()
    for character in string {
        if let count = characterCount[character] {
            characterCount[character] = count + 1
        } else {
            characterCount[character] = 1
        }
    }
    var isOddCount = false
    for (_, count) in characterCount {
        if count % 2!= 0 {
            if isOddCount {
                return false
            }
            isOddCount = true
        }
    }
    return true
}

// Given a string, return true if it is a permutation of a palindrome, and false otherwise.
// Note: a palindrome is a word, phrase, number, or other sequence of characters that reads the same forward and backward.
// isPermutationOfPalindrome(string: "Tact Coa") == true
// isPermutationOfPalindrome(string: "hello") == false
func isPermutationOfPalindrome3(string: String) -> Bool {
    var characterCount = [Character: Int]()
    for character in string {
        if let count = characterCount[character] {
            characterCount[character] = count + 1
        } else {
            characterCount[character] = 1
        }
    }
    var isOddCount = false
    for (_, count) in characterCount {
        if count % 2!=

func countDistinctCharacters(string: String) -> Int {
    var count = 0
    var visited: [Character: Bool] = [:]
    
    for char in string {
        if visited[char] == nil {
            count += 1
            visited[char] = true
        }
    }
    
    return count
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var count = 0
    var visited: [Character: Bool] = [:]
    
    for char in string {
        if visited[char] == nil {
            count += 1
            visited[char] = true
        }
    }
    
    return count
}

countDistinctCharacters(string: "xyzXYZ") == 3
countDistinctCharacters(string: "Jerry") == 4
```

func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

func getFirstNonRepeatingCharacter(string: String) -> Character? {
    var characters = [Character: Int]()
    for character in string {
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    for character in string {
        if characters[character] == 1 {
            return character
        }
    }
    return nil
}

func getFirstNonRepeatingCharacter(string: String, startingAfter: Character) -> Character? {
    var characters = [Character: Int]()
    var seen = Set<Character>()
    for character in string {
        if character == startingAfter {
            continue
        }
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    for character in string {
        if character == startingAfter || seen.contains(character) {
            continue
        }
        if characters[character] == 1 {
            return character
        }
        seen.insert(character)
    }
    return nil
}

func getLastNonRepeatingCharacter(string: String) -> Character? {
    var characters = [Character: Int]()
    for character in string {
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    for character in string.reversed() {
        if characters[character] == 1 {
            return character
        }
    }
    return nil
}

func getLastNonRepeatingCharacter(string: String, startingBefore: Character) -> Character? {
    var characters = [Character: Int]()
    var seen = Set<Character>()
    for character in string.reversed() {
        if character == startingBefore {
            continue
        }
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    for character in string.reversed() {
        if character == startingBefore || seen.contains(character) {
            continue
        }
        if characters[character] == 1 {
            return character
        }
        seen.insert(character)
    }
    return nil
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

// Given a string, return the first non-repeating character. If there is no such character, return nil.
// getFirstNonRepeatingCharacter(string: "abcdb") == "d"
// getFirstNonRepeatingCharacter(string: "Jerry") == "J"
// getFirstNonRepeatingCharacter(string: "abcaab") == nil
func getFirstNonRepeatingCharacter(string: String) -> Character? {
    var characters = [Character: Int]()
    for character in string {
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    for character in string {
        if characters[character] == 1 {
            return character
        }
    }
    return nil
}

// Given a string, return the first non-repeating character that appears after a specific character.
// If there is no such character, return nil.
// getFirstNonRepeatingCharacter(string: "abcdb", startingAfter: "b") == "c"
// getFirstNonRepeatingCharacter(string: "Jerry", startingAfter: "J") == nil
// getFirstNonRepeatingCharacter(string: "abcaab", startingAfter: "b") == nil
func getFirstNonRepeatingCharacter(string: String, startingAfter: Character) -> Character? {
    var characters = [Character: Int]()
    var seen = Set<Character>()
    for character in string {
        if character == startingAfter {
            continue
        }
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    for character in string {
        if character == startingAfter || seen.contains(character) {
            continue
        }
        if characters[character] == 1 {
            return character
        }
        seen.insert(character)
    }
    return nil
}

// Given a string, return the last non-repeating character. If there is no such character, return nil.
// getLastNonRepeatingCharacter(string: "abcdb") == "b"
// getLastNonRepeatingCharacter(string: "Jerry") == "J"
// getLastNonRepeatingCharacter(string: "abcaab") == nil
func getLastNonRepeatingCharacter(string: String) -> Character? {
    var characters = [Character: Int]()
    for character in string {
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    for character in string.reversed() {
        if characters[character] == 1 {
            return character
        }
    }
    return nil
}

// Given a string, return the last non-repeating character that appears before a specific character.
// If there is no such character, return nil.
// getLastNonRepeatingCharacter(string: "abcdb", startingBefore: "b") == "a"
// getLastNonRepeatingCharacter(string: "Jerry", startingBefore: "J") == nil
// getLastNonRepeatingCharacter(string: "abcaab", startingBefore: "b") == nil
func getLastNonRepeatingCharacter(string: String, startingBefore: Character) -> Character? {
    var characters = [Character: Int]()
    var seen = Set<Character>()
    for character in string.reversed() {
        if character == startingBefore {
            continue
        }
        if let count = characters[character] {
            characters[character] = count + 1
        } else {
            characters[character] = 1
        }
    }
    for character in string.reversed() {
        if character == startingBefore || seen.contains(character) {
            continue
        }
        if characters[character] == 1 {
            return character
        }
        seen.insert(character)
    }
    return nil
}

// Given a string, return the longest substring that does not contain repeating characters.
// getLongestSubstringWithoutRepeatingCharacters(string: "abcdb") == "abc"
// getLongestSubstringWithoutRepeatingCharacters(string: "Jerry") == "Jer"
// getLongestSubstringWithoutRepeatingCharacters(string: "abcaab") == "abca"
func getLongestSubstringWithoutRepeatingCharacters

func countDistinctCharacters(string: String) -> Int {
    var characters = Set<Character>()
    for character in string {
        characters.insert(character)
    }
    return characters.count
}

func getProductsOfAllOtherNumbers(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for index in 0..<input.count {
        products[index] = leftProduct
        leftProduct *= input[index]
    }
    var rightProduct = 1
    for index in (0..<input.count).reversed() {
        products[index] *= rightProduct
        rightProduct *= input[index]
    }
    return products
}

func getProductsOfAllOtherNumbersConstantSpace(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for index in 0..<input.count {
        products[index] = leftProduct
        leftProduct *= input[index]
    }
    var rightProduct = 1
    for index in (0..<input.count).reversed() {
        products[index] *= rightProduct
        rightProduct *= input[index]
    }
    return products
}

func getProductsOfAllOtherNumbersConstantSpaceV2(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for index in 0..<input.count {
        products[index] = leftProduct
        leftProduct *= input[index]
    }
    var rightProduct = 1
    for index in (0..<input.count).reversed() {
        products[index] *= rightProduct
        rightProduct *= input[index]
    }
    return products
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var characters = Set<Character>()
    for character in string {
        characters.insert(character)
    }
    return characters.count
}

// Given an array of integers, return a new array such that each element at index i of the new array
// is the product of all the numbers in the original array except the one at i.
// Note: You will not solve this problem without using division.
// Example:
// Input: [1, 2, 3, 4, 5]
// Output: [120, 60, 40, 30, 24]
// Follow-up: Can you solve it with constant space complexity? (Note: The output array does not count as extra space for space complexity analysis.)
func getProductsOfAllOtherNumbers(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for index in 0..<input.count {
        products[index] = leftProduct
        leftProduct *= input[index]
    }
    var rightProduct = 1
    for index in (0..<input.count).reversed() {
        products[index] *= rightProduct
        rightProduct *= input[index]
    }
    return products
}

// Given an array of integers, return a new array such that each element at index i of the new array
// is the product of all the numbers in the original array except the one at i.
// Note: You will not solve this problem without using division.
// Example:
// Input: [1, 2, 3, 4, 5]
// Output: [120, 60, 40, 30, 24]
// Follow-up: Can you solve it with constant space complexity? (Note: The output array does not count as extra space for space complexity analysis.)
func getProductsOfAllOtherNumbersConstantSpace(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for index in 0..<input.count {
        products[index] = leftProduct
        leftProduct *= input[index]
    }
    var rightProduct = 1
    for index in (0..<input.count).reversed() {
        products[index] *= rightProduct
        rightProduct *= input[index]
    }
    return products
}

// Given an array of integers, return a new array such that each element at index i of the new array
// is the product of all the numbers in the original array except the one at i.
// Note: You will not solve this problem without using division.
// Example:
// Input: [1, 2, 3, 4, 5]
// Output: [120, 60, 40, 30, 24]
// Follow-up: Can you solve it with constant space complexity? (Note: The output array does not count as extra space for space complexity analysis.)
func getProductsOfAllOtherNumbersConstantSpaceV2(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for index in 0..<input.count {
        products[index] = leftProduct
        leftProduct *= input[index]
    }
    var rightProduct = 1
    for index in (0..<input.count).reversed() {
        products[index] *= rightProduct
        rightProduct *= input[index]
    }
    return products
}

// Given an array of integers, return a new array such that each element at index i of the new array
// is the product of all the numbers in the original array except the one at i.
// Note: You will not solve this problem without using division.
// Example:
// Input: [1, 2, 3, 4, 5]
// Output: [120, 60, 40, 30, 24]
// Follow-up: Can you solve it with constant space complexity? (Note: The output array does not count as extra space for space complexity analysis.)
func getProductsOfAllOtherNumbersConstantSpaceV3(input: [Int]) -> [Int] {
    var products = [Int](repeating: 1, count: input.count)
    var leftProduct = 1
    for index in 0..<input.count {
        products[index] = leftProduct
        leftProduct *=

func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

func getProductsOfAllOtherElements(input: [Int]) -> [Int] {
    var products = [1]
    for i in 1..<input.count {
        products.append(products[i - 1] * input[i - 1])
    }
    var rightProduct = 1
    var output = [Int]()
    for i in (0..<input.count).reversed() {
        output.append(rightProduct)
        rightProduct *= input[i]
        if i > 0 {
            output[i] *= products[i - 1]
        }
    }
    return output
}

func checkPermutation(s1: String, s2: String) -> Bool {
    guard s1.count == s2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for character in s1 {
        charCounts[character, default: 0] += 1
    }
    for character in s2 {
        charCounts[character, default: 0] -= 1
        if charCounts[character] == -1 {
            return false
        }
    }
    return true
}

func checkPermutation2(s1: String, s2: String) -> Bool {
    guard s1.count == s2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for (i, character) in s1.enumerated() {
        charCounts[character, default: 0] += 1
        if charCounts[character] == 2 {
            charCounts[character] = 0
        } else {
            charCounts[character] = 1
        }
    }
    for (i, character) in s2.enumerated() {
        charCounts[character, default: 0] -= 1
        if charCounts[character] == -2 {
            charCounts[character] = 0
        } else {
            charCounts[character] = -1
        }
        if charCounts[character] == 1 {
            return false
        }
    }
    return true
}

func checkPermutation3(s1: String, s2: String) -> Bool {
    guard s1.count == s2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for character in s1 {
        charCounts[character, default: 0] += 1
    }
    for character in s2 {
        charCounts[character, default: 0] -= 1
        if charCounts[character] == 0 {
            charCounts[character] = -1
        } else if charCounts[character] == -1 {
            return false
        }
    }
    return true
}

```swift
// Given a string, find out how many distinct characters (regardless of case) does it consist of
// countDistinctCharacters(string: "xyzXYZ") == 3
// countDistinctCharacters(string: "Jerry") == 4
func countDistinctCharacters(string: String) -> Int {
    var distinctCharacters = Set<Character>()
    for character in string {
        distinctCharacters.insert(character)
    }
    return distinctCharacters.count
}

// Given an array of integers, return a new array such that each element at index i of the new array
// is the product of all the numbers in the original array except the one at i.
// Note: You will not solve this problem without using division.
// Example:
// Input: [1, 2, 3, 4, 5]
// Output: [120, 60, 40, 30, 24]
// Follow-up: Can you solve it with constant space complexity? (Note: The output array does not count as extra space for space complexity analysis.)
func getProductsOfAllOtherElements(input: [Int]) -> [Int] {
    var products = [1]
    for i in 1..<input.count {
        products.append(products[i - 1] * input[i - 1])
    }
    var rightProduct = 1
    var output = [Int]()
    for i in (0..<input.count).reversed() {
        output.append(rightProduct)
        rightProduct *= input[i]
        if i > 0 {
            output[i] *= products[i - 1]
        }
    }
    return output
}

// Given two strings, write a method to decide if one is a permutation of the other.
// Example:
// s1 = "abcd"
// s2 = "dcab"
// Return true.
// s1 = "abcd"
// s2 = "dabc"
// Return false.
func checkPermutation(s1: String, s2: String) -> Bool {
    guard s1.count == s2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for character in s1 {
        charCounts[character, default: 0] += 1
    }
    for character in s2 {
        charCounts[character, default: 0] -= 1
        if charCounts[character] == -1 {
            return false
        }
    }
    return true
}

// Given two strings, write a method to decide if one is a permutation of the other.
// Example:
// s1 = "abcd"
// s2 = "dcab"
// Return true.
// s1 = "abcd"
// s2 = "dabc"
// Return false.
func checkPermutation2(s1: String, s2: String) -> Bool {
    guard s1.count == s2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for (i, character) in s1.enumerated() {
        charCounts[character, default: 0] += 1
        if charCounts[character] == 2 {
            charCounts[character] = 0
        } else {
            charCounts[character] = 1
        }
    }
    for (i, character) in s2.enumerated() {
        charCounts[character, default: 0] -= 1
        if charCounts[character] == -2 {
            charCounts[character] = 0
        } else {
            charCounts[character] = -1
        }
        if charCounts[character] == 1 {
            return false
        }
    }
    return true
}

// Given two strings, write a method to decide if one is a permutation of the other.
// Example:
// s1 = "abcd"
// s2 = "dcab"
// Return true.
// s1 = "abcd"
// s2 = "dabc"
// Return false.
func checkPermutation3(s1: String, s2: String) -> Bool {
    guard s1.count == s2.count else {
        return false
    }
    var charCounts = [Character: Int]()
    for character in s1 {
        charCounts[character, default: 0] += 1
    }
    for character in s2 {
        charCounts[character, default: 0] -= 1
        if charCounts[character] == 0 {
            charCounts[character] = -1
        } else if charCounts[character] == -1 {
            return false
        }
    }
    return true
}

// Given two strings, write a method to decide if one is a permutation of the other.
// Example:
// s1 = "abcd"
// s2 = "dcab"
// Return true.
//

func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var currentBeat = 0
    for char in musicString {
        switch char {
        case "o":
            currentBeat += 4
        case "o|":
            currentBeat += 2
        case ".|":
            currentBeat += 1
        default:
            break
        }
        result.append(currentBeat)
    }
    return result
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var currentBeat = 0
    for char in musicString {
        switch char {
        case "o":
            currentBeat += 4
        case "o|":
            currentBeat += 2
        case ".|":
            currentBeat += 1
        default:
            break
        }
        result.append(currentBeat)
    }
    return result
}

// Example usage
let musicString = "o o|.| o| o|.|.|.|.| o o"
let beats = parseMusic(musicString: musicString)
print(beats)
// Output: [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]

let musicString2 = "o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o"
let beats2 = parseMusic(musicString: musicString2)
print(beats2)
// Output: [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]

let musicString3 = "o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o

func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var beatCount = 0
    for char in musicString {
        if char == "o" {
            beatCount += 4
        } else if char == "o|" {
            beatCount += 2
        } else if char == "." {
            beatCount += 1
        }
        result.append(beatCount)
    }
    return result
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var beatCount = 0
    for char in musicString {
        if char == "o" {
            beatCount += 4
        } else if char == "o|" {
            beatCount += 2
        } else if char == "." {
            beatCount += 1
        }
        result.append(beatCount)
    }
    return result
}

// Tests
assert(parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4])
assert(parseMusic(musicString: "o. o| o. o| o. o| o. o| o. o| o. o| o. o| o. o") == [1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4])
assert(parseMusic(musicString: "o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o| o o") == [4, 4, 4, 4, 4, 4, 4,

func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var currentBeat = 0
    for char in musicString {
        if char == "o" {
            currentBeat += 4
        } else if char == "o|" {
            currentBeat += 2
        } else if char == "." {
            currentBeat += 1
        }
        result.append(currentBeat)
    }
    return result
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var currentBeat = 0
    for char in musicString {
        if char == "o" {
            currentBeat += 4
        } else if char == "o|" {
            currentBeat += 2
        } else if char == "." {
            currentBeat += 1
        }
        result.append(currentBeat)
    }
    return result
}

// Example usage
let musicString = "o o|.| o| o|.|.|.|.| o o"
let beats = parseMusic(musicString: musicString)
print(beats)

// Additional edge case tests
let edgeCase1 = "o o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o|

func parseMusic(musicString: String) -> [Int] {
    var beats = [Int]()
    var beat = 0
    for char in musicString {
        switch char {
        case "o":
            beat += 4
        case "o|":
            beat += 2
        case ".|":
            beat += 1
        default:
            break
        }
        beats.append(beat)
    }
    return beats
}

func parseMusic(musicArray: [Int]) -> String {
    var musicString = ""
    for beat in musicArray {
        switch beat {
        case 4:
            musicString += "o"
        case 2:
            musicString += "o|"
        case 1:
            musicString += ".|"
        default:
            break
        }
    }
    return musicString
}

func countTotalBeats(musicString: String) -> Int {
    var totalBeats = 0
    for char in musicString {
        switch char {
        case "o":
            totalBeats += 4
        case "o|":
            totalBeats += 2
        case ".|":
            totalBeats += 1
        default:
            break
        }
    }
    return totalBeats
}

func countTotalBeats(musicArray: [Int]) -> Int {
    var totalBeats = 0
    for beat in musicArray {
        totalBeats += beat
    }
    return totalBeats
}

func countQuarterNotes(musicString: String) -> Int {
    var quarterNotes = 0
    for char in musicString {
        switch char {
        case ".|":
            quarterNotes += 1
        default:
            break
        }
    }
    return quarterNotes
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var beats = [Int]()
    var beat = 0
    for char in musicString {
        switch char {
        case "o":
            beat += 4
        case "o|":
            beat += 2
        case ".|":
            beat += 1
        default:
            break
        }
        beats.append(beat)
    }
    return beats
}

// Input to this function is an array of integers representing musical notes in a special ASCII format.
// Your task is to parse this array and return string representing the same notes in a special format,
// but now with the length of each note represented in beats.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicArray: [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]) == "o o|.| o| o|.|.|.|.| o o"
func parseMusic(musicArray: [Int]) -> String {
    var musicString = ""
    for beat in musicArray {
        switch beat {
        case 4:
            musicString += "o"
        case 2:
            musicString += "o|"
        case 1:
            musicString += ".|"
        default:
            break
        }
    }
    return musicString
}

// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return the total number of beats in the song.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == 32
func countTotalBeats(musicString: String) -> Int {
    var totalBeats = 0
    for char in musicString {
        switch char {
        case "o":
            totalBeats += 4
        case "o|":
            totalBeats += 2
        case ".|":
            totalBeats += 1
        default:
            break
        }
    }
    return totalBeats
}

// Input to this function is an array of integers representing musical notes in a special ASCII format.
// Your task is to parse this array and return the total number of beats in the song.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// countTotalBeats(musicArray: [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]) == 32
func countTotalBeats(musicArray: [Int]) -> Int {
    var totalBeats = 0
    for beat in musicArray {
        totalBeats += beat
    }
    return totalBeats
}

// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return the total number of quater notes in the song.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// countQuarterNotes(musicString: "o o|.| o| o|.|.|.|.| o o") == 8
func countQuarterNotes(musicString: String) -> Int {
    var quarterNotes = 0
    for char in musicString {
        switch char {
        case ".|":
            quarterNotes += 1
        default:
            break
        }
    }
    return quarterNotes
}

// Input to this function is an array of integers representing musical notes in a special ASCII format.
// Your task is to parse this array and return the total number of quater notes in the song.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// countQuarterNotes(musicArray: [

func parseMusic(musicString: String) -> [Int] {
    var beats = [Int]()
    var beat = 0
    for char in musicString {
        switch char {
        case "o":
            beat += 4
        case "o|":
            beat += 2
        case ".|":
            beat += 1
        default:
            break
        }
        beats.append(beat)
    }
    return beats
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var beats = [Int]()
    var beat = 0
    for char in musicString {
        switch char {
        case "o":
            beat += 4
        case "o|":
            beat += 2
        case ".|":
            beat += 1
        default:
            break
        }
        beats.append(beat)
    }
    return beats
}

// Example usage:
let musicString = "o o|.| o| o|.|.|.|.| o o"
let beats = parseMusic(musicString: musicString)
print(beats) // [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
```

func parseMusic(musicString: String) -> [Int] {
    var result: [Int] = []
    var beatCount = 0
    for char in musicString {
        switch char {
        case "o":
            beatCount += 4
        case "o|":
            beatCount += 2
        case ".|":
            beatCount += 1
        default:
            break
        }
        result.append(beatCount)
    }
    return result
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var result: [Int] = []
    var beatCount = 0
    for char in musicString {
        switch char {
        case "o":
            beatCount += 4
        case "o|":
            beatCount += 2
        case ".|":
            beatCount += 1
        default:
            break
        }
        result.append(beatCount)
    }
    return result
}

// Example usage
let musicString = "o o|.| o| o|.|.|.|.| o o"
let beats = parseMusic(musicString: musicString)
print(beats)
// Output: [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]

let musicString2 = "o o o| o o o| o o o| o o o| o o o| o o o"
let beats2 = parseMusic(musicString: musicString2)
print(beats2)
// Output: [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]

let musicString3 = "o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o"
let beats3 = parseMusic(musicString: musicString3)
print(beats3)
// Output: [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]

let musicString4 = "o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o"
let beats4 = parseMusic(musicString: musicString4)
print(beats4)
// Output: [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]

let musicString5 = "o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o"
let beats5 = parseMusic(musicString: musicString5)
print(beats5)
// Output: [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]

let musicString6 = "o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o"
let beats6 = parseMusic(musicString: musicString6)
print(beats6)
// Output: [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]

let musicString7 = "o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o"
let beats7 = parseMusic(musicString: musicString7)
print(beats7)
// Output: [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]

let musicString8 = "o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o| o o o"
let beats8 = parseMusic(musicString

func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var currentBeat = 0
    for char in musicString {
        switch char {
        case "o":
            currentBeat += 4
        case "o|":
            currentBeat += 2
        case ".|":
            currentBeat += 1
        default:
            continue
        }
        result.append(currentBeat)
    }
    return result
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var currentBeat = 0
    for char in musicString {
        switch char {
        case "o":
            currentBeat += 4
        case "o|":
            currentBeat += 2
        case ".|":
            currentBeat += 1
        default:
            continue
        }
        result.append(currentBeat)
    }
    return result
}

// Example usage
let musicString = "o o|.| o| o|.|.|.|.| o o"
let beats = parseMusic(musicString: musicString)
print(beats) // [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]

// Additional test cases
let test1 = "o o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o

func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var beatCount = 0
    for char in musicString {
        switch char {
        case "o":
            beatCount += 4
        case "o|":
            beatCount += 2
        case ".|":
            beatCount += 1
        default:
            break
        }
        result.append(beatCount)
    }
    return result
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var beatCount = 0
    for char in musicString {
        switch char {
        case "o":
            beatCount += 4
        case "o|":
            beatCount += 2
        case ".|":
            beatCount += 1
        default:
            break
        }
        result.append(beatCount)
    }
    return result
}

// Example usage
let musicString = "o o|.| o| o|.|.|.|.| o o"
let beats = parseMusic(musicString: musicString)
print(beats)
// Output: [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]

// Another example usage
let anotherMusicString = "o o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o| o|

func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var beatCount = 0
    for char in musicString {
        if char == "o" {
            beatCount += 4
        } else if char == "o|" {
            beatCount += 2
        } else if char == "." {
            beatCount += 1
        }
        result.append(beatCount)
    }
    return result
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var result = [Int]()
    var beatCount = 0
    for char in musicString {
        if char == "o" {
            beatCount += 4
        } else if char == "o|" {
            beatCount += 2
        } else if char == "." {
            beatCount += 1
        }
        result.append(beatCount)
    }
    return result
}

// Tests
assert(parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4])
assert(parseMusic(musicString: "o o. o| o. o. o| o. o. o| o. o. o| o. o. o") == [4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1])
assert(parseMusic(musicString: "o o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o") == [4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1])
assert(parseMusic(musicString: "o o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o") == [4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1])
assert(parseMusic(musicString: "o o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o") == [4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1])
assert(parseMusic(musicString: "o o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o") == [4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1])
assert(parseMusic(musicString: "o o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o") == [4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1])
assert(parseMusic(musicString: "o o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o") == [4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1])
assert(parseMusic(musicString: "o o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o| o. o. o") == [4, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 

func parseMusic(musicString: String) -> [Int] {
    var result: [Int] = []
    var beatCount = 0
    for char in musicString {
        if char == "o" {
            beatCount += 4
        } else if char == "o|" {
            beatCount += 2
        } else if char == "." {
            beatCount += 1
        }
        result.append(beatCount)
    }
    return result
}

```swift
// Input to this function is a string representing musical notes in a special ASCII format.
// Your task is to parse this string and return array of integers corresponding to how many beats does each
// not last.
// Here is a legend:
// 'o' - whole note, lasts four beats
// 'o|' - half note, lasts two beats
// '.|' - quater note, lasts one beat
// parseMusic(musicString: "o o|.| o| o|.|.|.|.| o o") == [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
func parseMusic(musicString: String) -> [Int] {
    var result: [Int] = []
    var beatCount = 0
    for char in musicString {
        if char == "o" {
            beatCount += 4
        } else if char == "o|" {
            beatCount += 2
        } else if char == "." {
            beatCount += 1
        }
        result.append(beatCount)
    }
    return result
}

// Example usage
let musicString = "o o|.| o| o|.|.|.|.| o o"
let beats = parseMusic(musicString: musicString)
print(beats) // [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
```

func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        if string[i] == substring[0] {
            var isMatch = true
            for j in 1..<substring.count {
                if string[i + j]!= substring[j] {
                    isMatch = false
                    break
                }
            }
            if isMatch {
                count += 1
            }
        }
    }
    return count
}

func longestNonDuplicateSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0..<string.count {
        for j in i..<string.count {
            let substring = String(string[i..<j])
            if substring.count > longest.count && isUnique(string: substring) {
                longest = substring
            }
        }
    }
    return longest
}

func isUnique(string: String) -> Bool {
    var chars = [Character: Bool]()
    for char in string {
        if chars[char] == nil {
            chars[char] = true
        } else {
            return false
        }
    }
    return true
}

func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

func isPalindrome(string: String) -> Bool {
    return reverse(string: string) == string
}

func removeDuplicates(string: String) -> String {
    var result = ""
    var chars = [Character: Bool]()
    for char in string {
        if chars[char] == nil {
            chars[char] = true
            result += "\(char)"
        }
    }
    return result
}

func removeSpaces(string: String) -> String {
    return string.replacingOccurrences(of: " ", with: "")
}

func isValidNumber(string: String) -> Bool {
    return string.range(of: "^[0-9]+$", options:.regularExpression)!= nil
}

func isValidEmail(string: String) -> Bool {
    return string.range(of: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}", options:.regularExpression)!= nil
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        if string[i] == substring[0] {
            var isMatch = true
            for j in 1..<substring.count {
                if string[i + j]!= substring[j] {
                    isMatch = false
                    break
                }
            }
            if isMatch {
                count += 1
            }
        }
    }
    return count
}

// Find the longest substring in a given string that does not contain duplicate characters.
// longestNonDuplicateSubstring(string: "abcabcbb") == "abc"
// longestNonDuplicateSubstring(string: "bbbbb") == "b"
// longestNonDuplicateSubstring(string: "pwwkew") == "wke"
func longestNonDuplicateSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0..<string.count {
        for j in i..<string.count {
            let substring = String(string[i..<j])
            if substring.count > longest.count && isUnique(string: substring) {
                longest = substring
            }
        }
    }
    return longest
}

// Check if a given string contains only unique characters.
// isUnique(string: "abc") == true
// isUnique(string: "aaa") == false
// isUnique(string: "aabc") == false
func isUnique(string: String) -> Bool {
    var chars = [Character: Bool]()
    for char in string {
        if chars[char] == nil {
            chars[char] = true
        } else {
            return false
        }
    }
    return true
}

// Reverse a given string.
// reverse(string: "Hello, World!") == "!dlroW,olleH"
func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

// Check if a given string is a palindrome.
// isPalindrome(string: "racecar") == true
// isPalindrome(string: "hello") == false
func isPalindrome(string: String) -> Bool {
    return reverse(string: string) == string
}

// Remove duplicate characters from a given string.
// removeDuplicates(string: "abcdcba") == "abcda"
// removeDuplicates(string: "aabbcc") == "abc"
func removeDuplicates(string: String) -> String {
    var result = ""
    var chars = [Character: Bool]()
    for char in string {
        if chars[char] == nil {
            chars[char] = true
            result += "\(char)"
        }
    }
    return result
}

// Remove spaces from a given string.
// removeSpaces(string: "Hello, World!") == "HelloWorld"
// removeSpaces(string: "  Hello,   World!  ") == "HelloWorld"
func removeSpaces(string: String) -> String {
    return string.replacingOccurrences(of: " ", with: "")
}

// Check if a given string is a valid number.
// isValidNumber(string: "123") == true
// isValidNumber(string: "12a3") == false
// isValidNumber(string: "12 3") == false
func isValidNumber(string: String) -> Bool {
    return string.range(of: "^[0-9]+$", options:.regularExpression)!= nil
}

// Check if a given string is a valid email address.
// isValidEmail(string: "[email protected]") == true
// isValidEmail(string: "example@example") == false
// isValidEmail(string: "[email protected]") == false
func isValidEmail(string: String) -> Bool {
    return string.range(of: "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}", options:.regularExpression)!= nil
}

// Check if a given string is a valid phone number.
// isValidPhoneNumber(string: "555-555-5555") == true
// isValidPhoneNumber

func howManyTimes(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(index!, offsetBy: substring.count, limitedBy: string.endIndex)
        index = string.firstIndex(of: substring.first!, range: index!.range(of: substring))
    }
    return count
}

func howManyTimes2(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(index!, offsetBy: substring.count, limitedBy: string.endIndex)
        index = string.index(of: substring.first!, range: index!.range(of: substring))
    }
    return count
}

func howManyTimes3(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(of: substring.first!, range: index!.range(of: substring))
    }
    return count
}

func howManyTimes4(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(of: substring.first!, offsetBy: substring.count, limitedBy: string.endIndex)
        index = string.index(of: substring.first!, range: index!.range(of: substring))
    }
    return count
}

func howManyTimes5(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(of: substring.first!, offsetBy: substring.count, limitedBy: string.endIndex)
        index = string.index(of: substring.first!, offsetBy: substring.count, limitedBy: index!)
    }
    return count
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(index!, offsetBy: substring.count, limitedBy: string.endIndex)
        index = string.firstIndex(of: substring.first!, range: index!.range(of: substring))
    }
    return count
}

// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes2(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(index!, offsetBy: substring.count, limitedBy: string.endIndex)
        index = string.index(of: substring.first!, range: index!.range(of: substring))
    }
    return count
}

// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes3(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(of: substring.first!, range: index!.range(of: substring))
    }
    return count
}

// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes4(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(of: substring.first!, offsetBy: substring.count, limitedBy: string.endIndex)
        index = string.index(of: substring.first!, range: index!.range(of: substring))
    }
    return count
}

// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes5(string: String, substring: String) -> Int {
    guard!string.isEmpty &&!substring.isEmpty else { return 0 }
    var count = 0
    var index = string.firstIndex(of: substring.first!)
    while index!= nil {
        count += 1
        index = string.index(of: substring.first!, offsetBy: substring.count, limitedBy: string.endIndex)
        index = string.index(of: substring.first!, offsetBy: substring.count, limitedBy: index!)
    }
    return count
}

// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes6(string: String, substring: String

func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        var match = true
        for j in 0..<substring.count {
            if string[i + j]!= substring[j] {
                match = false
                break
            }
        }
        if match {
            count += 1
        }
    }
    return count
}

func longestUniqueSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    var current = ""
    var seen = [Character: Int]()
    for char in string {
        if let lastIndex = seen[char] {
            if current.count > longest.count {
                longest = current
            }
            current = String(Array(string)[lastIndex...])
        }
        current += String(char)
        seen[char] = current.count - 1
    }
    if current.count > longest.count {
        longest = current
    }
    return longest
}

func longestPalindrome(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0..<string.count {
        let odd = longestPalindromeFrom(i, i, string)
        let even = longestPalindromeFrom(i, i + 1, string)
        let candidate = odd.count > even.count? odd : even
        if candidate.count > longest.count {
            longest = candidate
        }
    }
    return longest
}

func longestPalindromeFrom(_ left: Int, _ right: Int, _ string: String) -> String {
    var longest = ""
    while left >= 0 && right < string.count && string[left] == string[right] {
        let candidate = String(Array(string)[left...right])
        if candidate.count > longest.count {
            longest = candidate
        }
        left -= 1
        right += 1
    }
    return longest
}

func smallestSubstring(string: String, characters: String) -> String {
    guard string.count > 0 && characters.count > 0 else { return "" }
    var smallest = ""
    for i in 0...string.count - characters.count {
        var match = true
        for j in 0..<characters.count {
            if string[i + j]!= characters[j] {
                match = false
                break
            }
        }
        if match {
            if smallest.count == 0 || smallest.count > i + characters.count {
                smallest = String(Array(string)[i...i + characters.count - 1])
            }
        }
    }
    return smallest
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        var match = true
        for j in 0..<substring.count {
            if string[i + j]!= substring[j] {
                match = false
                break
            }
        }
        if match {
            count += 1
        }
    }
    return count
}

// Find the longest substring of a given string that only contains unique characters.
// longestUniqueSubstring(string: "abcabcbb") == "abc"
// longestUniqueSubstring(string: "bbbbb") == "b"
// longestUniqueSubstring(string: "pwwkew") == "wke"
func longestUniqueSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    var current = ""
    var seen = [Character: Int]()
    for char in string {
        if let lastIndex = seen[char] {
            if current.count > longest.count {
                longest = current
            }
            current = String(Array(string)[lastIndex...])
        }
        current += String(char)
        seen[char] = current.count - 1
    }
    if current.count > longest.count {
        longest = current
    }
    return longest
}

// Find the longest palindrome in a given string.
// longestPalindrome(string: "babad") == "bab"
// longestPalindrome(string: "cbbd") == "bb"
// longestPalindrome(string: "a") == "a"
// longestPalindrome(string: "ac") == "a"
func longestPalindrome(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0..<string.count {
        let odd = longestPalindromeFrom(i, i, string)
        let even = longestPalindromeFrom(i, i + 1, string)
        let candidate = odd.count > even.count? odd : even
        if candidate.count > longest.count {
            longest = candidate
        }
    }
    return longest
}

func longestPalindromeFrom(_ left: Int, _ right: Int, _ string: String) -> String {
    var longest = ""
    while left >= 0 && right < string.count && string[left] == string[right] {
        let candidate = String(Array(string)[left...right])
        if candidate.count > longest.count {
            longest = candidate
        }
        left -= 1
        right += 1
    }
    return longest
}

// Find the smallest substring of a given string that contains all the characters of a second string.
// smallestSubstring(string: "abcdabcdefg", characters: "bcd") == "bcd"
// smallestSubstring(string: "abcdabcdefg", characters: "z") == ""
// smallestSubstring(string: "abcdefg", characters: "abcdefg") == "abcdefg"
func smallestSubstring(string: String, characters: String) -> String {
    guard string.count > 0 && characters.count > 0 else { return "" }
    var smallest = ""
    for i in 0...string.count - characters.count {
        var match = true
        for j in 0..<characters.count {
            if string[i + j]!= characters[j] {
                match = false
                break
            }
        }
        if match {
            if smallest.count == 0 || smallest.count > i + characters.count {
                smallest = String(Array(string)[i...i + characters.count - 1])
            }
        }
    }
    return smallest
}

// Find the longest common substring between two strings.
// longestCommonSubstring(string1: "abcdxyz", string2: "xyzabcd") == "xyz"
// longestCommonSubstring(string1: "abcd", string2: "xyz") == ""
// longestCommonSubstring(string1: "abcde", string2: "acfgh") == "acfgh"
func longestCommonSubstring(string1: String, string2: String) -> String {
    guard string1.count > 0 && string2.count > 0 else { return "" }
    var longest = ""
    for i in 0...string1.count - 1

func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0...(string.count - substring.count) {
        if string[i..<i+substring.count] == substring {
            count += 1
        }
    }
    return count
}

func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0...a.count {
        for j in 0...b.count {
            if i + j > longest.count {
                let substring = a[i..<i+j]
                if howManyTimes(string: b, substring: substring) > 0 {
                    longest = substring
                }
            }
        }
    }
    return longest
}

func longestCommonSubsequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0...a.count {
        for j in 0...b.count {
            if i + j > longest.count {
                let substring = a[i..<i+j]
                if howManyTimes(string: b, substring: substring) == 1 {
                    longest = substring
                }
            }
        }
    }
    return longest
}

func shortestCommonSupersequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var shortest = ""
    for i in 0...a.count {
        for j in 0...b.count {
            if i + j < shortest.count {
                let substring = a[i..<i+j]
                if howManyTimes(string: b, substring: substring) == 1 {
                    shortest = substring
                }
            }
        }
    }
    return shortest
}

func longestPalindromeSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0...string.count {
        for j in 0...i {
            let substring = string[i-j..<i]
            if substring == String(substring.reversed()) && substring.count > longest.count {
                longest = substring
            }
        }
    }
    return longest
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0...(string.count - substring.count) {
        if string[i..<i+substring.count] == substring {
            count += 1
        }
    }
    return count
}

// Find the longest common substring between two strings.
// longestCommonSubstring(a: "abcba", b: "abccba") == "bcb"
// longestCommonSubstring(a: "abcd", b: "efgh") == ""
func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0...a.count {
        for j in 0...b.count {
            if i + j > longest.count {
                let substring = a[i..<i+j]
                if howManyTimes(string: b, substring: substring) > 0 {
                    longest = substring
                }
            }
        }
    }
    return longest
}

// Find the longest common subsequence between two strings.
// longestCommonSubsequence(a: "abc", b: "def") == "def"
// longestCommonSubsequence(a: "abc", b: "defg") == "defg"
// longestCommonSubsequence(a: "abc", b: "abef") == "abef"
func longestCommonSubsequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0...a.count {
        for j in 0...b.count {
            if i + j > longest.count {
                let substring = a[i..<i+j]
                if howManyTimes(string: b, substring: substring) == 1 {
                    longest = substring
                }
            }
        }
    }
    return longest
}

// Find the shortest common supersequence between two strings.
// shortestCommonSupersequence(a: "abcd", b: "efgh") == "abcdefgh"
// shortestCommonSupersequence(a: "abc", b: "defg") == "abcdefg"
// shortestCommonSupersequence(a: "abc", b: "abef") == "abcdef"
func shortestCommonSupersequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var shortest = ""
    for i in 0...a.count {
        for j in 0...b.count {
            if i + j < shortest.count {
                let substring = a[i..<i+j]
                if howManyTimes(string: b, substring: substring) == 1 {
                    shortest = substring
                }
            }
        }
    }
    return shortest
}

// Find the longest palindrome substring in a string.
// longestPalindromeSubstring(string: "babad") == "bab"
// longestPalindromeSubstring(string: "cbbd") == "bb"
func longestPalindromeSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0...string.count {
        for j in 0...i {
            let substring = string[i-j..<i]
            if substring == String(substring.reversed()) && substring.count > longest.count {
                longest = substring
            }
        }
    }
    return longest
}

// Find the longest palindrome subsequence in a string.
// longestPalindromeSubsequence(string: "babad") == "bab"
// longestPalindromeSubsequence(string: "cbbd") == "bb"
func longestPalindromeSubsequence(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0...string.count {
        for j in 0...i {
            let substring = string[i-j..<i]
            if substring == String(substring.reversed()) && substring.count > longest.count {
                longest = substring
            }
        }
    }
    return

func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        if string[i..<i + substring.count] == substring {
            count += 1
        }
    }
    return count
}

func longestUniqueSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    var current = ""
    var seen = [Character: Int]()
    for char in string {
        if let seenIndex = seen[char] {
            if current.count > longest.count {
                longest = current
            }
            current = String(Array(string)[seenIndex...])
        }
        current.append(char)
        seen[char] = current.count
    }
    if current.count > longest.count {
        longest = current
    }
    return longest
}

func longestCommonPrefix(_ strings: [String]) -> String {
    guard strings.count > 0 else { return "" }
    var prefix = strings[0]
    for i in 1..<strings.count {
        while!strings[i].hasPrefix(prefix) {
            prefix = String(prefix.dropLast())
            if prefix.isEmpty {
                return ""
            }
        }
    }
    return prefix
}

func squared(_ numbers: [Int]) -> [Int] {
    var squared = [Int]()
    for number in numbers {
        squared.append(number * number)
    }
    return squared
}

func cubed(_ numbers: [Int]) -> [Int] {
    var cubed = [Int]()
    for number in numbers {
        cubed.append(number * number * number)
    }
    return cubed
}

func incrementedByOne(_ numbers: [Int]) -> [Int] {
    var incremented = [Int]()
    for number in numbers {
        incremented.append(number + 1)
    }
    return incremented
}

func decrementedByOne(_ numbers: [Int]) -> [Int] {
    var decremented = [Int]()
    for number in numbers {
        decremented.append(number - 1)
    }
    return decremented
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        if string[i..<i + substring.count] == substring {
            count += 1
        }
    }
    return count
}

// Find the longest substring of a given string that only contains unique characters.
// longestUniqueSubstring(string: "abcabcbb") == "abc"
// longestUniqueSubstring(string: "bbbbb") == "b"
// longestUniqueSubstring(string: "pwwkew") == "wke"
func longestUniqueSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    var current = ""
    var seen = [Character: Int]()
    for char in string {
        if let seenIndex = seen[char] {
            if current.count > longest.count {
                longest = current
            }
            current = String(Array(string)[seenIndex...])
        }
        current.append(char)
        seen[char] = current.count
    }
    if current.count > longest.count {
        longest = current
    }
    return longest
}

// Find the longest common prefix in an array of strings.
// longestCommonPrefix(["flower", "flow", "flight", "fleet"]) == "fl"
// longestCommonPrefix(["dog", "racecar", "car"]) == ""
func longestCommonPrefix(_ strings: [String]) -> String {
    guard strings.count > 0 else { return "" }
    var prefix = strings[0]
    for i in 1..<strings.count {
        while!strings[i].hasPrefix(prefix) {
            prefix = String(prefix.dropLast())
            if prefix.isEmpty {
                return ""
            }
        }
    }
    return prefix
}

// Given an array of integers, return a new array of the same length that contains the original values squared.
// Example:
// squared([-1, 2, 3]) == [1, 4, 9]
// squared([0, 1, 5]) == [0, 1, 25]
func squared(_ numbers: [Int]) -> [Int] {
    var squared = [Int]()
    for number in numbers {
        squared.append(number * number)
    }
    return squared
}

// Given an array of integers, return a new array of the same length that contains the original values cubed.
// Example:
// cubed([-1, 2, 3]) == [-1, 8, 27]
// cubed([0, 1, 5]) == [0, 1, 125]
func cubed(_ numbers: [Int]) -> [Int] {
    var cubed = [Int]()
    for number in numbers {
        cubed.append(number * number * number)
    }
    return cubed
}

// Given an array of integers, return a new array of the same length that contains the original values incremented by 1.
// incrementedByOne([-1, 2, 3]) == [0, 3, 4]
// incrementedByOne([0, 1, 5]) == [1, 2, 6]
func incrementedByOne(_ numbers: [Int]) -> [Int] {
    var incremented = [Int]()
    for number in numbers {
        incremented.append(number + 1)
    }
    return incremented
}

// Given an array of integers, return a new array of the same length that contains the original values decremented by 1.
// decrementedByOne([-1, 2, 3]) == [-2, 1, 2]
// decrementedByOne([0, 1, 5]) == [-1, 0, 4]
func decrementedByOne(_ numbers: [Int]) -> [Int] {
    var decremented = [Int]()
    for number in numbers {
        decremented.append(number - 1)
    }
    return decremented
}

// Given an array of integers, return a new array of the same length that contains the original values multiplied by 2.
// multipliedByTwo([-1, 2, 3]) == [-2, 

func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        var isFound = true
        for j in 0..<substring.count {
            if string[i + j]!= substring[j] {
                isFound = false
                break
            }
        }
        if isFound {
            count += 1
        }
    }
    return count
}

func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var isFound = true
                while isFound && i + k < a.count && j + k < b.count {
                    if a[i + k]!= b[j + k] {
                        isFound = false
                    }
                    k += 1
                }
                if isFound && k > longest.count {
                    longest = String(a[i..<i + k])
                }
            }
        }
    }
    return longest
}

func longestCommonSubsequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var isFound = true
                while isFound && i + k < a.count && j + k < b.count {
                    if a[i + k]!= b[j + k] {
                        isFound = false
                    }
                    k += 1
                }
                if isFound && k > longest.count {
                    longest = String(a[i..<i + k])
                }
            }
        }
    }
    return longest
}

func shortestCommonSupersequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var shortest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var isFound = true
                while isFound && i + k < a.count && j + k < b.count {
                    if a[i + k]!= b[j + k] {
                        isFound = false
                    }
                    k += 1
                }
                if isFound && k < shortest.count {
                    shortest = String(a[i..<i + k])
                }
            }
        }
    }
    if shortest.count == 0 {
        shortest = a + b
    }
    return shortest
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        var isFound = true
        for j in 0..<substring.count {
            if string[i + j]!= substring[j] {
                isFound = false
                break
            }
        }
        if isFound {
            count += 1
        }
    }
    return count
}

// Find the longest common substring between two strings.
// longestCommonSubstring(a: "abcba", b: "abccba") == "bcb"
// longestCommonSubstring(a: "abcba", b: "dcba") == "a"
func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var isFound = true
                while isFound && i + k < a.count && j + k < b.count {
                    if a[i + k]!= b[j + k] {
                        isFound = false
                    }
                    k += 1
                }
                if isFound && k > longest.count {
                    longest = String(a[i..<i + k])
                }
            }
        }
    }
    return longest
}

// Find the longest common subsequence between two strings.
// longestCommonSubsequence(a: "abcba", b: "abccba") == "bcb"
// longestCommonSubsequence(a: "abcba", b: "dcba") == "abcba"
func longestCommonSubsequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var isFound = true
                while isFound && i + k < a.count && j + k < b.count {
                    if a[i + k]!= b[j + k] {
                        isFound = false
                    }
                    k += 1
                }
                if isFound && k > longest.count {
                    longest = String(a[i..<i + k])
                }
            }
        }
    }
    return longest
}

// Find the shortest common supersequence between two strings.
// shortestCommonSupersequence(a: "abcba", b: "abccba") == "abcbacbccba"
// shortestCommonSupersequence(a: "abcba", b: "dcba") == "adbcabcba"
func shortestCommonSupersequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var shortest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var isFound = true
                while isFound && i + k < a.count && j + k < b.count {
                    if a[i + k]!= b[j + k] {
                        isFound = false
                    }
                    k += 1
                }
                if isFound && k < shortest.count {
                    shortest = String(a[i..<i + k])
                }
            }
        }
    }
    if shortest.count == 0 {
        shortest = a + b
    }
    return shortest
}

// Find the longest palindrome substring in a given string.
// longestPalindromeSubstring(string: "abracadabraanamadamalayalamradar") == "anamadamalayalam"
func longestPalindromeSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0..<string.count {
        for j in 0..<string.count {
            var k = 0
            var isFound = true
            while is

func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        if string[i..<i+substring.count] == substring {
            count += 1
        }
    }
    return count
}

func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var substring = ""
                while i + k < a.count && j + k < b.count && a[i+k] == b[j+k] {
                    substring = String(a[i+k])
                    k += 1
                }
                if k > longest.count {
                    longest = substring
                }
            }
        }
    }
    return longest
}

func longestCommonSubsequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var subsequence = ""
                while i + k < a.count && j + k < b.count && a[i+k] == b[j+k] {
                    subsequence = String(a[i+k])
                    k += 1
                }
                if k > longest.count {
                    longest = subsequence
                }
            }
        }
    }
    return longest
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        if string[i..<i+substring.count] == substring {
            count += 1
        }
    }
    return count
}

// Find the longest common substring between two strings.
// longestCommonSubstring(a: "", b: "") == ""
// longestCommonSubstring(a: "a", b: "b") == ""
// longestCommonSubstring(a: "abc", b: "def") == ""
// longestCommonSubstring(a: "hello", b: "world") == "o"
// longestCommonSubstring(a: "cat", b: "dog") == ""
// longestCommonSubstring(a: "hello", b: "world") == "o"
// longestCommonSubstring(a: "hello", b: "earth") == "el"
// longestCommonSubstring(a: "cat", b: "dog") == ""
// longestCommonSubstring(a: "cat", b: "tac") == "at"
// longestCommonSubstring(a: "hello", b: "yellow") == "ello"
// longestCommonSubstring(a: "abcdefg", b: "acfgh") == "acf"
func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var substring = ""
                while i + k < a.count && j + k < b.count && a[i+k] == b[j+k] {
                    substring = String(a[i+k])
                    k += 1
                }
                if k > longest.count {
                    longest = substring
                }
            }
        }
    }
    return longest
}

// Find the longest common subsequence between two strings.
// longestCommonSubsequence(a: "", b: "") == ""
// longestCommonSubsequence(a: "a", b: "b") == ""
// longestCommonSubsequence(a: "abc", b: "def") == ""
// longestCommonSubsequence(a: "hello", b: "world") == "helo"
// longestCommonSubsequence(a: "cat", b: "dog") == "a"
// longestCommonSubsequence(a: "hello", b: "earth") == "hleo"
// longestCommonSubsequence(a: "cat", b: "dog") == "a"
// longestCommonSubsequence(a: "cat", b: "tac") == "at"
// longestCommonSubsequence(a: "hello", b: "yellow") == "hll"
// longestCommonSubsequence(a: "abcdefg", b: "acfgh") == "acfgh"
func longestCommonSubsequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 1
                var subsequence = ""
                while i + k < a.count && j + k < b.count && a[i+k] == b[j+k] {
                    subsequence = String(a[i+k])
                    k += 1
                }
                if k > longest.count {
                    longest = subsequence
                }
            }
        }
    }
    return longest
}

// Find the shortest common supersequence between two strings.
// shortestCommonSupersequence(a: "", b: "") == ""
// shortestCommonSupersequence(a: "a", b: "b") == "ab"
// shortestCommonSupersequence(a: "abc", b: "def") == "abcdef"
// shortestCommonSupersequence(a: "hello", b: "world") == "helloworld"
// shortestCommonSupersequence(a: "cat", b: "dog") == "catdog"
// shortestCommonSupersequence(a: "hello", b: "

func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    
    var count = 0
    var index = 0
    
    while index < string.count {
        if string[index] == substring[0] {
            var subIndex = 1
            while subIndex < substring.count && index + subIndex < string.count {
                if string[index + subIndex]!= substring[subIndex] {
                    break
                }
                subIndex += 1
            }
            if subIndex == substring.count {
                count += 1
            }
        }
        index += 1
    }
    
    return count
}

func longestCommonPrefix(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    guard a.count > 0 && b.count > 0 else { return a.count > b.count? a : b }
    
    var index = 0
    var result = ""
    
    while index < a.count && index < b.count {
        if a[index] == b[index] {
            result.append(a[index])
        } else {
            break
        }
        index += 1
    }
    
    return result
}

func longestCommonPrefix(strings: [String]) -> String {
    guard strings.count > 0 else { return "" }
    guard strings.count > 1 else { return strings[0] }
    
    var result = strings[0]
    
    for i in 1..<strings.count {
        result = longestCommonPrefix(a: result, b: strings[i])
        if result.count == 0 {
            break
        }
    }
    
    return result
}

func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    guard a.count > 0 && b.count > 0 else { return a.count > b.count? a : b }
    
    var result = ""
    var maxLength = 0
    
    for i in 0..<a.count {
        for j in 0..<b.count {
            var subIndex = 0
            while i + subIndex < a.count && j + subIndex < b.count {
                if a[i + subIndex] == b[j + subIndex] {
                    subIndex += 1
                } else {
                    break
                }
            }
            if subIndex > maxLength {
                maxLength = subIndex
                result = String(a[i..<i+subIndex])
            }
        }
    }
    
    return result
}

func longestCommonSubstring(strings: [String]) -> String {
    guard strings.count > 0 else { return "" }
    guard strings.count > 1 else { return strings[0] }
    
    var result = strings[0]
    
    for i in 1..<strings.count {
        result = longestCommonSubstring(a: result, b: strings[i])
        if result.count == 0 {
            break
        }
    }
    
    return result
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    
    var count = 0
    var index = 0
    
    while index < string.count {
        if string[index] == substring[0] {
            var subIndex = 1
            while subIndex < substring.count && index + subIndex < string.count {
                if string[index + subIndex]!= substring[subIndex] {
                    break
                }
                subIndex += 1
            }
            if subIndex == substring.count {
                count += 1
            }
        }
        index += 1
    }
    
    return count
}

// Find the longest common prefix of two strings.
// longestCommonPrefix(a: "", b: "") == ""
// longestCommonPrefix(a: "abc", b: "abc") == "abc"
// longestCommonPrefix(a: "abc", b: "abcd") == "ab"
func longestCommonPrefix(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    guard a.count > 0 && b.count > 0 else { return a.count > b.count? a : b }
    
    var index = 0
    var result = ""
    
    while index < a.count && index < b.count {
        if a[index] == b[index] {
            result.append(a[index])
        } else {
            break
        }
        index += 1
    }
    
    return result
}

// Find the longest common prefix of an array of strings.
// longestCommonPrefix(strings: []) == ""
// longestCommonPrefix(strings: ["abc", "abc"]) == "abc"
// longestCommonPrefix(strings: ["abc", "abcd", "abdc"]) == "ab"
func longestCommonPrefix(strings: [String]) -> String {
    guard strings.count > 0 else { return "" }
    guard strings.count > 1 else { return strings[0] }
    
    var result = strings[0]
    
    for i in 1..<strings.count {
        result = longestCommonPrefix(a: result, b: strings[i])
        if result.count == 0 {
            break
        }
    }
    
    return result
}

// Find the longest common substring of two strings.
// longestCommonSubstring(a: "", b: "") == ""
// longestCommonSubstring(a: "abc", b: "abc") == "abc"
// longestCommonSubstring(a: "abc", b: "abcd") == "ab"
func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    guard a.count > 0 && b.count > 0 else { return a.count > b.count? a : b }
    
    var result = ""
    var maxLength = 0
    
    for i in 0..<a.count {
        for j in 0..<b.count {
            var subIndex = 0
            while i + subIndex < a.count && j + subIndex < b.count {
                if a[i + subIndex] == b[j + subIndex] {
                    subIndex += 1
                } else {
                    break
                }
            }
            if subIndex > maxLength {
                maxLength = subIndex
                result = String(a[i..<i+subIndex])
            }
        }
    }
    
    return result
}

// Find the longest common substring of an array of strings.
// longestCommonSubstring(strings: []) == ""
// longestCommonSubstring(strings: ["abc", "abc"]) == "abc"
// longestCommonSubstring(strings: ["abc", "abcd", "abdc"]) == "ab"
func longestCommonSubstring(strings: [String]) -> String {
    guard strings.count > 0 else { return "" }
    guard strings.count > 1 else { return strings[0] }
    
    var result = strings[0]
    
    for i in 1..<strings.count {
        result = longestCommonSubstring(a: result, b: strings[i])
        if result.count == 0 {
            break
        }
    }
    
    return result
}

// Find the longest common subsequence of two strings.
// longestCommonSubsequence(a: "", b: "") == ""
// longestCommonSubsequence(a: "abc", b: "abc

func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        var j = 0
        while j < substring.count {
            if string[i + j]!= substring[j] {
                break
            }
            j += 1
        }
        if j == substring.count {
            count += 1
        }
    }
    return count
}

func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            var k = 0
            while k < a.count - i && k < b.count - j && a[i + k] == b[j + k] {
                k += 1
            }
            if k > longest.count {
                longest = String(a[i..<i + k])
            }
        }
    }
    return longest
}

func longestCommonSubsequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 0
                while k < a.count - i && k < b.count - j && a[i + k] == b[j + k] {
                    k += 1
                }
                if k > longest.count {
                    longest = String(a[i..<i + k])
                }
            }
        }
    }
    return longest
}

func shortestCommonSupersequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var shortest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 0
                while k < a.count - i && k < b.count - j && a[i + k] == b[j + k] {
                    k += 1
                }
                if k < shortest.count {
                    shortest = String(a[i..<i + k])
                }
            }
        }
    }
    if shortest.count == 0 {
        shortest = a + b
    }
    return shortest
}

func longestPalindromeSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0..<string.count {
        for j in 0..<string.count {
            var k = 0
            while k < string.count - i && k < string.count - j && string[i + k] == string[j + k] {
                k += 1
            }
            if k > longest.count {
                longest = String(string[i..<i + k])
            }
        }
    }
    return longest
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        var j = 0
        while j < substring.count {
            if string[i + j]!= substring[j] {
                break
            }
            j += 1
        }
        if j == substring.count {
            count += 1
        }
    }
    return count
}

// Find the longest common substring between two strings.
// longestCommonSubstring(a: "abc", b: "bc") == "bc"
// longestCommonSubstring(a: "abc", b: "def") == ""
func longestCommonSubstring(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            var k = 0
            while k < a.count - i && k < b.count - j && a[i + k] == b[j + k] {
                k += 1
            }
            if k > longest.count {
                longest = String(a[i..<i + k])
            }
        }
    }
    return longest
}

// Find the longest common subsequence between two strings.
// longestCommonSubsequence(a: "abc", b: "bc") == "b"
// longestCommonSubsequence(a: "abc", b: "def") == ""
func longestCommonSubsequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var longest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 0
                while k < a.count - i && k < b.count - j && a[i + k] == b[j + k] {
                    k += 1
                }
                if k > longest.count {
                    longest = String(a[i..<i + k])
                }
            }
        }
    }
    return longest
}

// Find the shortest common supersequence between two strings.
// shortestCommonSupersequence(a: "abc", b: "bc") == "abc"
// shortestCommonSupersequence(a: "abc", b: "def") == "abcdef"
func shortestCommonSupersequence(a: String, b: String) -> String {
    guard a.count > 0 && b.count > 0 else { return "" }
    var shortest = ""
    for i in 0..<a.count {
        for j in 0..<b.count {
            if a[i] == b[j] {
                var k = 0
                while k < a.count - i && k < b.count - j && a[i + k] == b[j + k] {
                    k += 1
                }
                if k < shortest.count {
                    shortest = String(a[i..<i + k])
                }
            }
        }
    }
    if shortest.count == 0 {
        shortest = a + b
    }
    return shortest
}

// Find the longest palindrome substring in a given string.
// longestPalindromeSubstring(string: "abracadabraanamadamalayalamradar") == "anamadamalayalam"
func longestPalindromeSubstring(string: String) -> String {
    guard string.count > 0 else { return "" }
    var longest = ""
    for i in 0..<string.count {
        for j in 0..<string.count {
            var k = 0
            while k < string.count - i && k < string.count - j && string[i + k] == string[j + k] {
                k += 1
            }
            if k > longest.count {
                longest = String(string[i..<i + k])
            }
        }
    }
    return longest
}

// Find the longest palindrome subsequence in a given string.
// longestPalindromeSubsequence(string: "abracadabraanamadamalayalamradar") == "an

func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        var match = true
        for j in 0..<substring.count {
            if string[i + j]!= substring[j] {
                match = false
                break
            }
        }
        if match {
            count += 1
        }
    }
    return count
}

func howManyTimes2(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    var i = 0
    while i < string.count {
        var match = true
        for j in 0..<substring.count {
            if i + j >= string.count || string[i + j]!= substring[j] {
                match = false
                break
            }
        }
        if match {
            count += 1
            i += substring.count
        } else {
            i += 1
        }
    }
    return count
}

func howManyTimes3(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    var i = 0
    while i < string.count {
        if string[i] == substring[0] {
            var match = true
            for j in 1..<substring.count {
                if i + j >= string.count || string[i + j]!= substring[j] {
                    match = false
                    break
                }
            }
            if match {
                count += 1
                i += substring.count
            } else {
                i += 1
            }
        } else {
            i += 1
        }
    }
    return count
}

func howManyTimes4(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    var i = 0
    while i < string.count {
        if string[i] == substring[0] {
            var match = true
            for j in 1..<substring.count {
                if i + j >= string.count || string[i + j]!= substring[j] {
                    match = false
                    break
                }
            }
            if match {
                count += 1
                i += substring.count
            } else {
                i += 1
            }
        } else {
            i += 1
        }
    }
    return count
}

```swift
// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes(string: "", substring: "a") == 0
// howManyTimes(string: "aaa", substring: "a") == 3
// howManyTimes(string: "aaaa", substring: "aa") == 3
func howManyTimes(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    for i in 0..<string.count - substring.count + 1 {
        var match = true
        for j in 0..<substring.count {
            if string[i + j]!= substring[j] {
                match = false
                break
            }
        }
        if match {
            count += 1
        }
    }
    return count
}

// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes2(string: "", substring: "a") == 0
// howManyTimes2(string: "aaa", substring: "a") == 3
// howManyTimes2(string: "aaaa", substring: "aa") == 3
func howManyTimes2(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    var i = 0
    while i < string.count {
        var match = true
        for j in 0..<substring.count {
            if i + j >= string.count || string[i + j]!= substring[j] {
                match = false
                break
            }
        }
        if match {
            count += 1
            i += substring.count
        } else {
            i += 1
        }
    }
    return count
}

// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes3(string: "", substring: "a") == 0
// howManyTimes3(string: "aaa", substring: "a") == 3
// howManyTimes3(string: "aaaa", substring: "aa") == 3
func howManyTimes3(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    var i = 0
    while i < string.count {
        if string[i] == substring[0] {
            var match = true
            for j in 1..<substring.count {
                if i + j >= string.count || string[i + j]!= substring[j] {
                    match = false
                    break
                }
            }
            if match {
                count += 1
                i += substring.count
            } else {
                i += 1
            }
        } else {
            i += 1
        }
    }
    return count
}

// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes4(string: "", substring: "a") == 0
// howManyTimes4(string: "aaa", substring: "a") == 3
// howManyTimes4(string: "aaaa", substring: "aa") == 3
func howManyTimes4(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
    var i = 0
    while i < string.count {
        if string[i] == substring[0] {
            var match = true
            for j in 1..<substring.count {
                if i + j >= string.count || string[i + j]!= substring[j] {
                    match = false
                    break
                }
            }
            if match {
                count += 1
                i += substring.count
            } else {
                i += 1
            }
        } else {
            i += 1
        }
    }
    return count
}

// Find how many times a given substring can be found in the original string. Count overlaping cases.
// howManyTimes5(string: "", substring: "a") == 0
// howManyTimes5(string: "aaa", substring: "a") == 3
// howManyTimes5(string: "aaaa", substring: "aa") == 3
func howManyTimes5(string: String, substring: String) -> Int {
    guard substring.count > 0 else { return 0 }
    guard substring.count <= string.count else { return 0 }
    var count = 0
   

func sortNumbers(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted()
    return sortedNumbers.joined(separator: " ")
}

func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0 > $1 }
    return sortedWords.joined(separator: " ")
}

func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0.count > $1.count || $0 < $1 }
    return sortedWords.joined(separator: " ")
}

func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0.count > $1.count || $0 > $1 }
    return sortedWords.joined(separator: " ")
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted()
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted in reverse alphabetical order
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0 > $1 }
    return sortedWords.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length and alphabetically
// sortWords(words: "cat dog tie") == "cat dog tie"
func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0.count > $1.count || $0 < $1 }
    return sortedWords.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length and reverse alphabetical order
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0.count > $1.count || $0 > $1 }
    return sortedWords.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length and reverse alphabetical order
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0.count > $1.count || $0 > $1 }
    return sortedWords.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length and reverse alphabetical order
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0.count > $1.count || $0 > $1 }
    return sortedWords.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length and reverse alphabetical order
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0.count > $1.count || $0 > $1 }
    return sortedWords.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length and reverse alphabetical order
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0.count > $1.count || $0 > $1 }
    return sortedWords.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length and reverse alphabetical order
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let words = words.components(separatedBy:.whitespaces)
    var sortedWords = words.sorted { $0.count > $1.count || $0 > $1 }
    return sortedWords.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length and reverse alphabetical order
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let words = words.components(separated

func sortNumbers(numbers: String) -> String {
    var sortedNumbers = numbers.components(separatedBy:.whitespaces)
    sortedNumbers.sort()
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersDescending(numbers: String) -> String {
    var sortedNumbers = numbers.components(separatedBy:.whitespaces)
    sortedNumbers.sort(by: >)
    return sortedNumbers.joined(separator: " ")
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    var sortedNumbers = numbers.components(separatedBy:.whitespaces)
    sortedNumbers.sort()
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    var sortedNumbers = numbers.components(separatedBy:.whitespaces)
    sortedNumbers.sort(by: >)
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    var sortedNumbers = numbers.components(separatedBy:.whitespaces)
    sortedNumbers.sort()
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    var sortedNumbers = numbers.components(separatedBy:.whitespaces)
    sortedNumbers.sort(by: >)
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    var sortedNumbers = numbers.components(separatedBy:.whitespaces)
    sortedNumbers.sort()
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    var sortedNumbers = numbers.components(separatedBy:.whitespaces)
    sortedNumbers.sort(by: >)
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    var sortedNumbers = numbers.components(separatedBy:.whitespaces)
    sortedNumbers.sort()
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    var sortedNumbers = numbers.components(separated

func sortNumbers(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted()
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: >)
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersAscending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: <)
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersWithDuplicates(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: <)
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersWithDuplicatesDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: >)
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersWithDuplicatesAscending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: <)
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersWithDuplicatesAndNegative(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: >)
    return sortedNumbers.joined(separator: " ")
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted()
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: >)
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbersAscending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: <)
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbersWithDuplicates(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: <)
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersWithDuplicatesDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: >)
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbersWithDuplicatesAscending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: <)
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersWithDuplicatesAndNegative(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted(by: >)
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers

func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! < Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

func sortNumbersDescending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! > Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

func sortNumbersAscending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! < Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! < Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! > Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbersAscending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! < Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! > Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersAscending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! < Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! > Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersAscending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted {
        Int($0)! < Int($1)!
    }
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string

func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted()
    return sortedArray.joined(separator: " ")
}

func sortWords(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: >)
    return sortedArray.joined(separator: " ")
}

func sortWordsByLength(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: { $0.count > $1.count })
    return sortedArray.joined(separator: " ")
}

func sortWordsByLengthAndContent(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 > $1
        } else {
            return $0.count > $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

func sortWordsByLengthAndContentReverse(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 > $1
        } else {
            return $0.count < $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

func sortWordsByLengthAndContentAlphabetical(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 < $1
        } else {
            return $0.count > $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

func sortWordsByLengthAndContentAlphabeticalReverse(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 > $1
        } else {
            return $0.count < $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

func sortWordsByLengthAndContentReverseAlphabetical(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 > $1
        } else {
            return $0.count < $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted()
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted in reverse alphabetical order.
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: >)
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length in descending order.
// sortWords(words: "cat dog tie") == "cat dog tie"
func sortWordsByLength(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: { $0.count > $1.count })
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length in descending order.
// sortWords(words: "cat dog tie") == "cat dog tie"
func sortWordsByLengthAndContent(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 > $1
        } else {
            return $0.count > $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length in descending order.
// sortWords(words: "cat dog tie") == "cat dog tie"
func sortWordsByLengthAndContentReverse(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 > $1
        } else {
            return $0.count < $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length in descending order.
// sortWords(words: "cat dog tie") == "cat dog tie"
func sortWordsByLengthAndContentAlphabetical(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 < $1
        } else {
            return $0.count > $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length in descending order.
// sortWords(words: "cat dog tie") == "cat dog tie"
func sortWordsByLengthAndContentAlphabeticalReverse(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 > $1
        } else {
            return $0.count < $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of words.
// Return the string with words sorted by length in descending order.
// sortWords(words: "cat dog tie") == "cat dog tie"
func sortWordsByLengthAndContentReverseAlphabetical(words: String) -> String {
    let wordArray = words.components(separatedBy:.whitespaces)
    var sortedArray = wordArray.sorted(by: {
        if $0.count == $1.count {
            return $0 > $1
        } else {
            return $0.count < $1.count
        }
    })
    return sortedArray.joined(separator: " ")
}

// Input is a space

func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = [Int]()
    
    for number in numberArray {
        if let number = Int(number) {
            sortedArray.append(number)
        }
    }
    
    sortedArray.sort()
    
    var sortedNumbers = ""
    
    for number in sortedArray {
        sortedNumbers += String(number) + " "
    }
    
    return sortedNumbers
}

func sortLetters(letters: String) -> String {
    let letterArray = letters.components(separatedBy: " ")
    var sortedArray = [String]()
    
    for letter in letterArray {
        sortedArray.append(letter)
    }
    
    sortedArray.sort()
    
    var sortedLetters = ""
    
    for letter in sortedArray {
        sortedLetters += letter + " "
    }
    
    return sortedLetters
}

func sortWords(words: String) -> String {
    let wordArray = words.components(separatedBy: " ")
    var sortedArray = [String]()
    
    for word in wordArray {
        sortedArray.append(word)
    }
    
    sortedArray.sort()
    sortedArray.reverse()
    
    var sortedWords = ""
    
    for word in sortedArray {
        sortedWords += word + " "
    }
    
    return sortedWords
}

func sortNumbersAndLetters(numbersAndLetters: String) -> String {
    let numberAndLetterArray = numbersAndLetters.components(separatedBy: " ")
    var sortedArray = [String]()
    
    for numberAndLetter in numberAndLetterArray {
        if let number = Int(numberAndLetter) {
            sortedArray.append(String(number))
        } else {
            sortedArray.append(numberAndLetter)
        }
    }
    
    sortedArray.sort()
    
    var sortedNumbersAndLetters = ""
    
    for numberOrLetter in sortedArray {
        if let number = Int(numberOrLetter) {
            sortedNumbersAndLetters += String(number) + " "
        } else {
            sortedNumbersAndLetters += numberOrLetter + " "
        }
    }
    
    return sortedNumbersAndLetters
}

func sortNumbersAndLettersReverse(numbersAndLetters: String) -> String {
    let numberAndLetterArray = numbersAndLetters.components(separatedBy: " ")
    var sortedArray = [String]()
    
    for numberAndLetter in numberAndLetterArray {
        if let number = Int(numberAndLetter) {
            sortedArray.append(String(number))
        } else {
            sortedArray.append(numberAndLetter)
        }
    }
    
    sortedArray.sort()
    sortedArray.reverse()
    
    var sortedNumbersAndLetters = ""
    
    for numberOrLetter in sortedArray {
        if let number = Int(numberOrLetter) {
            sortedNumbersAndLetters += String(number) + " "
        } else {
            sortedNumbersAndLetters += numberOrLetter + " "
        }
    }
    
    return sortedNumbersAndLetters
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = [Int]()
    
    for number in numberArray {
        if let number = Int(number) {
            sortedArray.append(number)
        }
    }
    
    sortedArray.sort()
    
    var sortedNumbers = ""
    
    for number in sortedArray {
        sortedNumbers += String(number) + " "
    }
    
    return sortedNumbers
}

// Input is a space-delimited string of letters from 'a' to 'z'.
// Return the string with letters sorted in alphabetical order
// sortLetters(letters: "cat dog tie") == "cat dog tie"
func sortLetters(letters: String) -> String {
    let letterArray = letters.components(separatedBy: " ")
    var sortedArray = [String]()
    
    for letter in letterArray {
        sortedArray.append(letter)
    }
    
    sortedArray.sort()
    
    var sortedLetters = ""
    
    for letter in sortedArray {
        sortedLetters += letter + " "
    }
    
    return sortedLetters
}

// Input is a space-delimited string of words.
// Return the string with words sorted in reverse alphabetical order
// sortWords(words: "cat dog tie") == "tie dog cat"
func sortWords(words: String) -> String {
    let wordArray = words.components(separatedBy: " ")
    var sortedArray = [String]()
    
    for word in wordArray {
        sortedArray.append(word)
    }
    
    sortedArray.sort()
    sortedArray.reverse()
    
    var sortedWords = ""
    
    for word in sortedArray {
        sortedWords += word + " "
    }
    
    return sortedWords
}

// Input is a space-delimited string of numbers and letters from 'a' to 'z'.
// Return the string with numbers sorted from smallest to largest and letters sorted in reverse alphabetical order
// sortNumbersAndLetters(numbersAndLetters: "cat 1 dog 8 tie 3") == "cat 8 dog 3 tie 1"
func sortNumbersAndLetters(numbersAndLetters: String) -> String {
    let numberAndLetterArray = numbersAndLetters.components(separatedBy: " ")
    var sortedArray = [String]()
    
    for numberAndLetter in numberAndLetterArray {
        if let number = Int(numberAndLetter) {
            sortedArray.append(String(number))
        } else {
            sortedArray.append(numberAndLetter)
        }
    }
    
    sortedArray.sort()
    
    var sortedNumbersAndLetters = ""
    
    for numberOrLetter in sortedArray {
        if let number = Int(numberOrLetter) {
            sortedNumbersAndLetters += String(number) + " "
        } else {
            sortedNumbersAndLetters += numberOrLetter + " "
        }
    }
    
    return sortedNumbersAndLetters
}

// Input is a space-delimited string of numbers and letters from 'a' to 'z'.
// Return the string with numbers sorted from smallest to largest and letters sorted in alphabetical order
// sortNumbersAndLetters(numbersAndLetters: "cat 1 dog 8 tie 3") == "cat 1 dog 3 tie 8"
func sortNumbersAndLettersReverse(numbersAndLetters: String) -> String {
    let numberAndLetterArray = numbersAndLetters.components(separatedBy: " ")
    var sortedArray = [String]()
    
    for numberAndLetter in numberAndLetterArray {
        if let number = Int(numberAndLetter) {
            sortedArray.append(String(number))
        } else {
            sortedArray.append(numberAndLetter)
        }
    }
    
    sortedArray.sort()
    sortedArray.reverse()
    
    var sortedNumbersAndLetters = ""
    
    for numberOrLetter in sortedArray {
        if let number = Int(numberOrLetter) {
            sortedNumbersAndLetters += String(number) + " "
        } else {
            sortedNumbersAndLetters += numberOrLetter + " "
        }
    }
    
    return sortedNumbersAndLetters
}

// Input is a space-delimited string of numbers and letters from 'a' to 'z'.
// Return the string with letters sorted in alphabetical order and numbers sorted from smallest to largest
// sortLettersAndNumbers(lettersAndNumbers: "cat 1 dog 8 tie 3") == "cat 3 dog 8 tie 1"
func sortLettersAndNumbers(lettersAndNumbers: String) -> String {
    let numberAndLetterArray = lettersAndNumbers.components(separatedBy: " ")
    var sortedArray = [String]()
    
    for numberAndLetter in number

func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted()
    return sortedArray.joined(separator: " ")
}

func sortNumbersDescending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted(by: >)
    return sortedArray.joined(separator: " ")
}

func sortNumbersAscending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted(by: <)
    return sortedArray.joined(separator: " ")
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted()
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted(by: >)
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbersAscending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted(by: <)
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted()
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted(by: >)
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbersAscending(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted(by: <)
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy:.whitespaces)
    var sortedArray = numberArray.sorted()
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five")

func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted()
    return sortedArray.joined(separator: " ")
}

func reverseSortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: >)
    return sortedArray.joined(separator: " ")
}

func reverseSortNumbers2(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: { $0 > $1 })
    return sortedArray.joined(separator: " ")
}

func reverseSortNumbers3(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: >)
    return sortedArray.joined(separator: " ")
}

func reverseSortNumbers4(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: { $0 > $1 })
    return sortedArray.joined(separator: " ")
}

func sortNumbers2(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: { $0 < $1 })
    return sortedArray.joined(separator: " ")
}

func sortNumbers3(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: { $0 < $1 })
    return sortedArray.joined(separator: " ")
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted()
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func reverseSortNumbers(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: >)
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func reverseSortNumbers2(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: { $0 > $1 })
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func reverseSortNumbers3(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: >)
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func reverseSortNumbers4(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: { $0 > $1 })
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbers2(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: { $0 < $1 })
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbers3(numbers: String) -> String {
    let numberArray = numbers.components(separatedBy: " ")
    var sortedArray = numberArray.sorted(by: { $0 < $1 })
    return sortedArray.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers:

func sortNumbers(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! < Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! > Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersAscending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! < Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! < Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! > Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbersAscending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! < Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! > Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersAscending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! < Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! > Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersAscending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy: " ")
    var sortedNumbers = numbers.sorted {
        Int($0)! < Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven',

func sortNumbers(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        Int($0)! < Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        Int($0)! > Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersByDigitCount(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        $0.count > $1.count
    }
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersByDigitCountDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        $0.count < $1.count
    }
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersByDigitSum(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        Int(String($0))! + Int(String($1))! > Int(String($1))! + Int(String($0))!
    }
    return sortedNumbers.joined(separator: " ")
}

func sortNumbersByDigitSumDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        Int(String($0))! + Int(String($1))! < Int(String($1))! + Int(String($0))!
    }
    return sortedNumbers.joined(separator: " ")
}

```swift
// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from smallest to largest
// sortNumbers(numbers: "three one five") == "one three five"
func sortNumbers(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        Int($0)! < Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted from largest to smallest
// sortNumbers(numbers: "three one five") == "five three one"
func sortNumbersDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        Int($0)! > Int($1)!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order based on the number of digits
// sortNumbers(numbers: "three one five") == "three five one"
func sortNumbersByDigitCount(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        $0.count > $1.count
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order based on the number of digits
// sortNumbers(numbers: "three one five") == "five one three"
func sortNumbersByDigitCountDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        $0.count < $1.count
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order based on the number of digits
// sortNumbers(numbers: "three one five") == "three five one"
func sortNumbersByDigitSum(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        Int(String($0))! + Int(String($1))! > Int(String($1))! + Int(String($0))!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in descending order based on the number of digits
// sortNumbers(numbers: "three one five") == "five one three"
func sortNumbersByDigitSumDescending(numbers: String) -> String {
    let numbers = numbers.components(separatedBy:.whitespaces)
    var sortedNumbers = numbers.sorted {
        Int(String($0))! + Int(String($1))! < Int(String($1))! + Int(String($0))!
    }
    return sortedNumbers.joined(separator: " ")
}

// Input is a space-delimited string of numberals from 'zero' to 'nine'.
// Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five','six','seven', 'eight' and 'nine'.
// Return the string with numbers sorted in ascending order based on the number of digits
// sortNumbers(numbers: "three one five") == "three five one"
func sortNumbersByDigitSumAndDigitCount(

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[1])
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.8)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [0.0, 1.0, 2.0]) == (0.0, 1.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[1])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0]) == (1.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[1])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 4.0, 5.0, 3.0]) == (3.0, 4.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.8)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number,

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else {
        fatalError("Array must contain at least two numbers")
    }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else {
        fatalError("Array must contain at least two numbers")
    }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2])
findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0])

//: [Next](@next)

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[1])
}

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[0])
}

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (0.0, 0.0)
}

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[2])
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.8)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [0.0, 1.0, 2.0]) == (0.0, 1.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[1])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0]) == (1.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[1])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0]) == (1.0, 1.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[0])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: []) == (0.0, 0.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (0.0, 0.0)
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 5.0, 10.0]) == (1.0, 10.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    
    return (numbers[0], numbers[2])
}

// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 5.0, 10.0, 100.0]) == (1.0, 100

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    var numbers = numbers
    numbers.sort()
    let smallest = numbers[0]
    let largest = numbers[numbers.count - 1]
    var smallestDifference = largest - smallest
    var result: (Double, Double) = (smallest, largest)
    for i in 0..<numbers.count {
        let difference = numbers[i] - smallest
        if difference < smallestDifference {
            smallestDifference = difference
            result = (smallest, numbers[i])
        }
    }
    return result
}

func findClosestElements(numbers: [Double]) -> (Double, Double, Double) {
    var numbers = numbers
    numbers.sort()
    let smallest = numbers[0]
    let middle = numbers[numbers.count / 2]
    let largest = numbers[numbers.count - 1]
    var smallestDifference = largest - smallest
    var middleDifference = largest - middle
    var result: (Double, Double, Double) = (smallest, middle, largest)
    for i in 0..<numbers.count {
        let difference = numbers[i] - smallest
        if difference < smallestDifference {
            smallestDifference = difference
            result = (smallest, numbers[i], largest)
        }
        let difference2 = numbers[i] - middle
        if difference2 < middleDifference {
            middleDifference = difference2
            result = (smallest, middle, numbers[i])
        }
    }
    return result
}

func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double) {
    var numbers = numbers
    numbers.sort()
    let smallest = numbers[0]
    let middle1 = numbers[numbers.count / 2 - 1]
    let middle2 = numbers[numbers.count / 2]
    let largest = numbers[numbers.count - 1]
    var smallestDifference = largest - smallest
    var middleDifference1 = largest - middle1
    var middleDifference2 = largest - middle2
    var result: (Double, Double, Double, Double) = (smallest, middle1, middle2, largest)
    for i in 0..<numbers.count {
        let difference = numbers[i] - smallest
        if difference < smallestDifference {
            smallestDifference = difference
            result = (smallest, numbers[i], middle1, largest)
        }
        let difference2 = numbers[i] - middle1
        if difference2 < middleDifference1 {
            middleDifference1 = difference2
            result = (smallest, middle1, numbers[i], largest)
        }
        let difference3 = numbers[i] - middle2
        if difference3 < middleDifference2 {
            middleDifference2 = difference3
            result = (smallest, middle1, middle2, numbers[i])
        }
    }
    return result
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    var numbers = numbers
    numbers.sort()
    let smallest = numbers[0]
    let largest = numbers[numbers.count - 1]
    var smallestDifference = largest - smallest
    var result: (Double, Double) = (smallest, largest)
    for i in 0..<numbers.count {
        let difference = numbers[i] - smallest
        if difference < smallestDifference {
            smallestDifference = difference
            result = (smallest, numbers[i])
        }
    }
    return result
}

findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2])
findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0])

// From a supplied array of numbers (of length at least three) select and return three that are the closest to each
// other and return them in order (smallest number, middle number, largest number).
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 3.0, 5.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double) {
    var numbers = numbers
    numbers.sort()
    let smallest = numbers[0]
    let middle = numbers[numbers.count / 2]
    let largest = numbers[numbers.count - 1]
    var smallestDifference = largest - smallest
    var middleDifference = largest - middle
    var result: (Double, Double, Double) = (smallest, middle, largest)
    for i in 0..<numbers.count {
        let difference = numbers[i] - smallest
        if difference < smallestDifference {
            smallestDifference = difference
            result = (smallest, numbers[i], largest)
        }
        let difference2 = numbers[i] - middle
        if difference2 < middleDifference {
            middleDifference = difference2
            result = (smallest, middle, numbers[i])
        }
    }
    return result
}

findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0])

// From a supplied array of numbers (of length at least four) select and return four that are the closest to each
// other and return them in order (smallest number, middle number, middle number, largest number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 5.0]) == (2.0, 2.5, 3.0, 5.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double) {
    var numbers = numbers
    numbers.sort()
    let smallest = numbers[0]
    let middle1 = numbers[numbers.count / 2 - 1]
    let middle2 = numbers[numbers.count / 2]
    let largest = numbers[numbers.count - 1]
    var smallestDifference = largest - smallest
    var middleDifference1 = largest - middle1
    var middleDifference2 = largest - middle2
    var result: (Double, Double, Double, Double) = (smallest, middle1, middle2, largest)
    for i in 0..<numbers.count {
        let difference = numbers[i] - smallest
        if difference < smallestDifference {
            smallestDifference = difference
            result = (smallest, numbers[i], middle1, largest)
        }
        let difference2 = numbers[i] - middle1
        if difference2 < middleDifference1 {
            middleDifference1 = difference2
            result = (smallest, middle1, numbers[i], largest)
        }
        let difference3 = numbers[i] - middle2
        if difference3 < middleDifference2 {
            middleDifference2 = difference3
            result = (smallest, middle1, middle2, numbers[i])
        }
    }
    return result
}

findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 5.0])

// From a supplied array of numbers (of length at least four) select and return four that are the closest to each
// other and return them in order (smallest number, middle number, middle number, largest number).
// findClosestElements

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else {
        fatalError("There must be at least two numbers")
    }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else {
        fatalError("There must be at least two numbers")
    }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

// Test cases
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0))

// Negative numbers
assert(findClosestElements(numbers: [-1.0, -2.8, -3.0, -4.0, -5.0, -2.0]) == (-2.8, -2.0))

// Edge cases
assert(findClosestElements(numbers: [1.0]) == (1.0, 1.0))
assert(findClosestElements(numbers: [1.0, 2.0]) == (1.0, 2.0))
assert(findClosestElements(numbers: [2.0, 1.0]) == (1.0, 2.0))
assert(findClosestElements(numbers: [2.0, 1.0, 3.0]) == (1.0, 2.0))
assert(findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.8))

// Additional edge cases
assert(findClosestElements(numbers: [1.0, 1.0, 1.0]) == (1.0, 1.0))
assert(findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0, 2.0]) == (2.0, 2.8))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.8]) == (2.0, 2.8))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2, 2.8]) == (2.0, 2.8))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.0, 2.8]) == (2.0, 2.8))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2, 2.0, 2.8]) == (2.0, 2.8))

// Additional test cases
assert(findClosestElements(numbers: [1.0, 1.0, 1.0, 1.0]) == (1.0, 1.0))
assert(findClosestElements(numbers: [1.0, 1.8, 2.0, 2.0, 2.0, 2.0]) == (1.8, 2.0))
assert(findClosestElements(numbers: [1.0, 1.8, 2.0, 2.2, 2.0, 2.0]) == (1.8, 2.0))
assert(findClosestElements(numbers: [1.0, 1.8, 2.0, 2.2, 2.0, 2.0, 3.0]) == (1.8, 2.0))
assert(findClosestElements(numbers: [1.0, 1.8, 2.0, 2.2, 2.0, 2.0, 

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else {
        fatalError("Array must contain at least two elements")
    }
    
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

func findClosestElements(numbers: [Double]) -> (Double, Double, Double) {
    guard numbers.count >= 3 else {
        fatalError("Array must contain at least three elements")
    }
    
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[right])
}

func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double) {
    guard numbers.count >= 4 else {
        fatalError("Array must contain at least four elements")
    }
    
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[left + 2], numbers[right])
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else {
        fatalError("Array must contain at least two elements")
    }
    
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

// From a supplied array of numbers (of length at least three) select and return three that are the closest to each
// other and return them in order (smaller number, middle number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 3.0, 4.0)
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.8, 3.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double) {
    guard numbers.count >= 3 else {
        fatalError("Array must contain at least three elements")
    }
    
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[right])
}

// From a supplied array of numbers (of length at least four) select and return four that are the closest to each
// other and return them in order (smaller number, middle number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 3.0, 4.0, 5.0)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 10.0, 5.0, 2.0]) == (2.0, 3.0, 4.0, 5.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double) {
    guard numbers.count >= 4 else {
        fatalError("Array must contain at least four elements")
    }
    
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[left + 2], numbers[right])
}

// From a supplied array of numbers (of length at least five) select and return five that are the closest to each
// other and return them in order (smaller number, middle number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 3.0, 4.0, 5.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 10.0, 5.0, 2.0]) == (2.0, 3.0, 4.0, 5.0, 10.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double, Double) {
    guard numbers.count >= 5 else {
        fatalError("Array must contain at

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else {
        fatalError("Array must contain at least two elements")
    }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else {
        fatalError("Array must contain at least two elements")
    }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2])
findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0])

//: [Next](@next)

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

func findClosestElements(numbers: [Double]) -> (Double, Double, Double) {
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[right])
}

func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double) {
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 3 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[left + 2], numbers[right])
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2])
findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0])

// From a supplied array of numbers (of length at least three) select and return three that are closest to each other
// and return them in order (smallest number, middle number, largest number).
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 3.0, 4.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double) {
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 1 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[right])
}

findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0])

// From a supplied array of numbers (of length at least four) select and return four that are closest to each other
// and return them in order (smallest number, middle number, middle number, largest number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 5.0]) == (2.0, 2.5, 3.0, 5.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double) {
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 3 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[left + 2], numbers[right])
}

findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 5.0])

// From a supplied array of numbers (of length at least four) select and return four that are closest to each other
// and return them in order (smallest number, middle number, middle number, largest number).
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0, 2.0]) == (2.0, 2.5, 3.0, 5.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double) {
    var left = 0
    var right = numbers.count - 1
    var minDiff = abs(numbers[left] - numbers[right])
    
    while right - left > 3 {
        let mid = (left + right) / 2
        let diff = abs(numbers[mid] - numbers[mid - 1])
        if diff < minDiff {
            minDiff = diff
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[left +

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("not enough numbers") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

func findClosestElements(numbers: [Double]) -> (Double, Double, Double) {
    guard numbers.count >= 3 else { fatalError("not enough numbers") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 2 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[right])
}

func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double) {
    guard numbers.count >= 4 else { fatalError("not enough numbers") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 3 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[left + 2], numbers[right])
}

func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double, Double) {
    guard numbers.count >= 5 else { fatalError("not enough numbers") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 4 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[left + 2], numbers[left + 3], numbers[right])
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("not enough numbers") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 1 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[right])
}

// From a supplied array of numbers (of length at least three) select and return three that are the closest to each
// other and return them in order (smaller number, middle number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 3.0, 4.0)
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.8, 3.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double) {
    guard numbers.count >= 3 else { fatalError("not enough numbers") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 2 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[right])
}

// From a supplied array of numbers (of length at least four) select and return four that are the closest to each
// other and return them in order (smaller number, middle number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 3.0, 4.0, 5.0)
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.8, 3.0, 4.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double) {
    guard numbers.count >= 4 else { fatalError("not enough numbers") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 3 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[left + 2], numbers[right])
}

// From a supplied array of numbers (of length at least five) select and return five that are the closest to each
// other and return them in order (smaller number, middle number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 3.0, 4.0, 5.0, 2.2)
// findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.8, 3.0, 4.0, 5.0)
func findClosestElements(numbers: [Double]) -> (Double, Double, Double, Double, Double) {
    guard numbers.count >= 5 else { fatalError("not enough numbers") }
    
    var left = 0
    var right = numbers.count - 1
    
    while right - left > 4 {
        let mid = (left + right) / 2
        if numbers[mid] > numbers[left] {
            left = mid
        } else {
            right = mid
        }
    }
    
    return (numbers[left], numbers[left + 1], numbers[left + 2], numbers[left + 3], numbers[right])
}

// From a supplied array of numbers (of length at least six) select and return six that are the closest to each
// other and return them in order

func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    var numbers = numbers
    numbers.sort()
    
    let first = numbers[0]
    let last = numbers[numbers.count - 1]
    
    var firstIndex = 0
    var lastIndex = numbers.count - 1
    
    while lastIndex - firstIndex >= 1 {
        let midIndex = (firstIndex + lastIndex) / 2
        let mid = numbers[midIndex]
        if mid == first {
            return (first, last)
        } else if mid == last {
            return (last, first)
        } else if mid > first {
            firstIndex = midIndex
        } else {
            lastIndex = midIndex
        }
    }
    
    return (numbers[firstIndex], numbers[lastIndex])
}

```swift
// From a supplied array of numbers (of length at least two) select and return two that are the closest to each
// other and return them in order (smaller number, larger number).
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2)
// findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.0)
func findClosestElements(numbers: [Double]) -> (Double, Double) {
    guard numbers.count >= 2 else { fatalError("Array must contain at least two elements") }
    var numbers = numbers
    numbers.sort()
    
    let first = numbers[0]
    let last = numbers[numbers.count - 1]
    
    var firstIndex = 0
    var lastIndex = numbers.count - 1
    
    while lastIndex - firstIndex >= 1 {
        let midIndex = (firstIndex + lastIndex) / 2
        let mid = numbers[midIndex]
        if mid == first {
            return (first, last)
        } else if mid == last {
            return (last, first)
        } else if mid > first {
            firstIndex = midIndex
        } else {
            lastIndex = midIndex
        }
    }
    
    return (numbers[firstIndex], numbers[lastIndex])
}

// Tests
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.2]) == (2.0, 2.2))
assert(findClosestElements(numbers: [1.0, 2.8, 3.0, 4.0, 5.0, 2.0]) == (2.0, 2.8))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.2]) == (2.0, 2.2))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.8, 2.4]) == (2.0, 2.8))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.8, 2.4, 3.2, 3.1, 3.6]) == (2.0, 3.2))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.8, 2.4, 3.2, 3.1, 3.6, 3.5]) == (2.0, 3.2))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.8, 2.4, 3.2, 3.1, 3.6, 3.5, 3.7]) == (2.0, 3.2))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.8, 2.4, 3.2, 3.1, 3.6, 3.5, 3.7, 3.4]) == (2.0, 3.2))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.8, 2.4, 3.2, 3.1, 3.6, 3.5, 3.7, 3.4, 3.3]) == (2.0, 3.2))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.8, 2.4, 3.2, 3.1, 3.6, 3.5, 3.7, 3.4, 3.3, 3.8]) == (2.0, 3.2))
assert(findClosestElements(numbers: [1.0, 2.0, 3.0, 4.0, 5.0, 2.0, 2.8, 2.4, 3.2, 3.1, 3.6, 3.5, 3.7, 3.4, 3.3, 3.8, 3.

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescale

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = max - min
    return numbers.map { ($0 - min) / range }
}

func rescaleToUnit(numbers: [Float]) -> [Float] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = max - min
    return numbers.map { ($0 - min) / range }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = Double(max - min)
    return numbers.map { Double($0 - min) / range }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = Double(max - min)
    return numbers.map { Double($0 - min) / range }
}

func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = Double(max - min)
    return numbers.map { Double($0 - min) / range }
}

func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = Double(max - min)
    return numbers.map { Double($0 - min) / range }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = max - min
    return numbers.map { ($0 - min) / range }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Float]) -> [Float] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = max - min
    return numbers.map { ($0 - min) / range }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = Double(max - min)
    return numbers.map { Double($0 - min) / range }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = Double(max - min)
    return numbers.map { Double($0 - min) / range }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = Double(max - min)
    return numbers.map { Double($0 - min) / range }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = Double(max - min)
    return numbers.map { Double($0 - min) / range }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int64]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let range = Double(max - min)
    return numbers.map { Double($0 - min) /

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [UInt]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [UInt8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [UInt]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [UInt8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Float]) -> [Float] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

func rescaleToUnit(numbers: [Int64]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Float]) -> [Float] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int64]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { Double($0 - min) / Double(max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int64]) -> [Double] {

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = max - min
    return numbers.map { ($0 - min) / diff }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = max - min
    return numbers.map { ($0 - min) / diff }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    let diff = Double(max - min)
    return numbers.map { Double($0 - min) / diff }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [UInt]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [UInt]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Float]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [CGFloat]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescale

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Float]) -> [Float] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

func rescaleToUnit(numbers: [Int64]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Float]) -> [Float] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { ($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.75, 1]
func rescaleToUnit(numbers: [Int64]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1, 2, 3, 4, 5]) == [0, 0.25, 0.5, 0.

func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 - min }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Float]) -> [Float] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 - Float(min) }
              .map { $0 / (Float(max) - Float(min)) }
}

func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) }
              .map { $0 / (max - min) }
}

func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) }
              .map { $0 / (max - min) }
}

```swift
// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Double]) -> [Double] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 - min }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Float]) -> [Float] {
    let min = numbers.min()!
    let max = numbers.max()!
    return numbers.map { $0 - Float(min) }
              .map { $0 / (Float(max) - Float(min)) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int8]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int16]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int32]) -> [Double] {
    let min = Double(numbers.min()!)
    let max = Double(numbers.max()!)
    return numbers.map { Double($0 - min) }
              .map { $0 / (max - min) }
}

// Given array of numbers (of at least two elements), apply a linear transform to that array,
// such that the smallest number will become 0 and the largest will become 1
// rescaleToUnit(numbers: [1.0, 2.0, 3.0, 4.0, 5.0]) == [0.0, 0.25, 0.5, 0.75, 1.0]
func rescaleToUnit(numbers: [Int64]) -> [Double] {
    let min = Double(numbers

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap { value in
        if let stringValue = value as? String {
            return stringValue
        }
        return nil
    }
}

func filterDictionaries(values: [AnyHashable]) -> [AnyHashable : AnyHashable] {
    return values.compactMap { value in
        if let dictionaryValue = value as? [AnyHashable : AnyHashable] {
            return dictionaryValue
        }
        return nil
    }
}

func filterArrays(values: [AnyHashable]) -> [Any] {
    return values.compactMap { value in
        if let arrayValue = value as? [Any] {
            return arrayValue
        }
        return nil
    }
}

func filterSets(values: [AnyHashable]) -> Set<AnyHashable> {
    return values.compactMap { value in
        return value
    }
}

func filterTuples(values: [AnyHashable]) -> [(AnyHashable, AnyHashable)] {
    return values.compactMap { value in
        if let tupleValue = value as? (AnyHashable, AnyHashable) {
            return tupleValue
        }
        return nil
    }
}

func filterOptionalValues(values: [AnyHashable]) -> [AnyHashable] {
    return values.compactMap { value in
        return value
    }
}

enum Color: String, Hashable {
    case Red, Green, Blue
}

func filterEnums(values: [AnyHashable]) -> [Color] {
    return values.compactMap { value in
        if let enumValue = value as? Color {
            return enumValue
        }
        return nil
    }
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for strings
// filterStrings(values: ["a", 3.14, 5]) == ["a", "3.14"]
// filterStrings(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == ["abc"]
func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap { value in
        if let stringValue = value as? String {
            return stringValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for dictionaries
// filterDictionaries(values: ["a", 3.14, 5]) == []
// filterDictionaries(values: [1, 2, 3, "abc", [:], []]) == [:] as [AnyHashable : AnyHashable]
func filterDictionaries(values: [AnyHashable]) -> [AnyHashable : AnyHashable] {
    return values.compactMap { value in
        if let dictionaryValue = value as? [AnyHashable : AnyHashable] {
            return dictionaryValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for arrays
// filterArrays(values: ["a", 3.14, 5]) == []
// filterArrays(values: [1, 2, 3, "abc", [:], []]) == []
func filterArrays(values: [AnyHashable]) -> [Any] {
    return values.compactMap { value in
        if let arrayValue = value as? [Any] {
            return arrayValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for sets
// filterSets(values: ["a", 3.14, 5]) == []
// filterSets(values: [1, 2, 3, "abc", [:], []]) == []
func filterSets(values: [AnyHashable]) -> Set<AnyHashable> {
    return values.compactMap { value in
        return value
    }
}

// Filter given array of any swiftthon values only for tuples
// filterTuples(values: ["a", 3.14, 5]) == []
// filterTuples(values: [1, 2, 3, "abc", [:], []]) == []
func filterTuples(values: [AnyHashable]) -> [(AnyHashable, AnyHashable)] {
    return values.compactMap { value in
        if let tupleValue = value as? (AnyHashable, AnyHashable) {
            return tupleValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for optional values
// filterOptionalValues(values: ["a", 3.14, 5]) == ["a", 3.14, 5]
// filterOptionalValues(values: [1, 2, 3, "abc", [:], nil]) == [1, 2, 3, "abc", [:]]
func filterOptionalValues(values: [AnyHashable]) -> [AnyHashable] {
    return values.compactMap { value in
        return value
    }
}

// Filter given array of any swiftthon values only for enums
// filterEnums(values: ["a", 3.14, 5]) == []
// filterEnums(values: [1, 2, 3, "abc", [:], nil]) == []
// filterEnums(values: [Red, Green, Blue]) == [Red, Green, Blue]
enum Color: String, Hashable {
    case Red, Green, Blue
}
func filterEnums(values: [AnyHashable]) -> [Color] {
    return values.compactMap { value in
        if let enumValue = value as? Color {
            return enumValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for functions
// filterFunctions(values: ["a", 3.14, 5]) == []
// filterFunctions(values: [1, 2, 

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap { value in
        if let stringValue = value as? String {
            return stringValue
        }
        return nil
    }
}

func filterDictionaries(values: [AnyHashable]) -> [AnyDictionary] {
    return values.compactMap { value in
        if let dictionaryValue = value as? AnyDictionary {
            return dictionaryValue
        }
        return nil
    }
}

func filterArrays(values: [AnyHashable]) -> [AnyArray] {
    return values.compactMap { value in
        if let arrayValue = value as? AnyArray {
            return arrayValue
        }
        return nil
    }
}

func filterSets(values: [AnyHashable]) -> [AnySet] {
    return values.compactMap { value in
        if let setValue = value as? AnySet {
            return setValue
        }
        return nil
    }
}

func filterTuples(values: [AnyHashable]) -> [AnyTuple] {
    return values.compactMap { value in
        if let tupleValue = value as? AnyTuple {
            return tupleValue
        }
        return nil
    }
}

func filterEnums(values: [AnyHashable]) -> [AnyEnum] {
    return values.compactMap { value in
        if let enumValue = value as? AnyEnum {
            return enumValue
        }
        return nil
    }
}

func filterClasses(values: [AnyHashable]) -> [AnyClass] {
    return values.compactMap { value in
        if let classValue = value as? AnyClass {
            return classValue
        }
        return nil
    }
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            if let intValue = Int(stringValue) {
                return intValue
            }
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for strings
// filterStrings(values: ["a", 3.14, 5]) == ["a", "3.14"]
// filterStrings(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == ["abc"]
func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap { value in
        if let stringValue = value as? String {
            return stringValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for dictionaries
// filterDictionaries(values: ["a", 3.14, 5]) == []
// filterDictionaries(values: [1, 2, 3, "abc", [:], []]) == [[:]]
func filterDictionaries(values: [AnyHashable]) -> [AnyDictionary] {
    return values.compactMap { value in
        if let dictionaryValue = value as? AnyDictionary {
            return dictionaryValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for arrays
// filterArrays(values: ["a", 3.14, 5]) == []
// filterArrays(values: [1, 2, 3, "abc", [:], []]) == [[]]
func filterArrays(values: [AnyHashable]) -> [AnyArray] {
    return values.compactMap { value in
        if let arrayValue = value as? AnyArray {
            return arrayValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for sets
// filterSets(values: ["a", 3.14, 5]) == []
// filterSets(values: [1, 2, 3, "abc", [:], []]) == [[:]]
func filterSets(values: [AnyHashable]) -> [AnySet] {
    return values.compactMap { value in
        if let setValue = value as? AnySet {
            return setValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for tuples
// filterTuples(values: ["a", 3.14, 5]) == []
// filterTuples(values: [1, 2, 3, "abc", [:], []]) == []
func filterTuples(values: [AnyHashable]) -> [AnyTuple] {
    return values.compactMap { value in
        if let tupleValue = value as? AnyTuple {
            return tupleValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for enums
// filterEnums(values: ["a", 3.14, 5]) == []
// filterEnums(values: [1, 2, 3, "abc", [:], []]) == []
func filterEnums(values: [AnyHashable]) -> [AnyEnum] {
    return values.compactMap { value in
        if let enumValue = value as? AnyEnum {
            return enumValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for classes
// filterClasses(values: ["a", 3.14, 5]) == []
// filterClasses(values: [1, 2, 3, "abc", [:], []]) == []
func filterClasses(values: [AnyHashable]) -> [AnyClass] {
    return values.compactMap { value in
        if let classValue = value as? AnyClass {
            return classValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for functions
// filterFunctions(values: ["a", 3.14, 5]) == []
// filterFunctions(values: [1, 2, 3, "abc", [:], []]) == []
func filterFunctions(values: [AnyHashable]) -> [AnyFunction] {
    return values.compactMap { value in
        if let functionValue = value as? AnyFunction {
            return functionValue
        }
        return nil
    }

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
   

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

func filterIntegers(values: [Any]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [Any]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [Any]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [Any]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [Any]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            return Int(stringValue)
        } else if let arrayValue = value as? [AnyHashable] {
            return filterIntegers(values: arrayValue)
        } else if let dictValue = value as? [AnyHashable : AnyHashable] {
            return filterIntegers(values: Array(dictValue.values))
        }
        return nil
    }
}

func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap { value in
        if let stringValue = value as? String {
            return stringValue
        } else if let arrayValue = value as? [AnyHashable] {
            return filterStrings(values: arrayValue)
        } else if let dictValue = value as? [AnyHashable : AnyHashable] {
            return filterStrings(values: Array(dictValue.values))
        }
        return nil
    }
}

func filterDictionaries(values: [AnyHashable]) -> [AnyHashable : AnyHashable] {
    return values.compactMap { value in
        if let dictValue = value as? [AnyHashable : AnyHashable] {
            return dictValue
        } else if let arrayValue = value as? [AnyHashable] {
            return filterDictionaries(values: arrayValue)
        }
        return nil
    }
}

func filterArrays(values: [AnyHashable]) -> [[AnyHashable]] {
    return values.compactMap { value in
        if let arrayValue = value as? [AnyHashable] {
            return arrayValue
        } else if let dictValue = value as? [AnyHashable : AnyHashable] {
            return filterArrays(values: Array(dictValue.values))
        }
        return nil
    }
}

func flatten(values: [AnyHashable]) -> [AnyHashable] {
    var result: [AnyHashable] = []
    for value in values {
        if let arrayValue = value as? [AnyHashable] {
            result += flatten(values: arrayValue)
        } else {
            result.append(value)
        }
    }
    return result
}

func array(values: [AnyHashable]) -> [AnyHashable] {
    return values
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        } else if let doubleValue = value as? Double {
            return Int(doubleValue)
        } else if let stringValue = value as? String {
            return Int(stringValue)
        } else if let arrayValue = value as? [AnyHashable] {
            return filterIntegers(values: arrayValue)
        } else if let dictValue = value as? [AnyHashable : AnyHashable] {
            return filterIntegers(values: Array(dictValue.values))
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for strings
// filterStrings(values: ["a", 3.14, 5]) == ["a", "3.14"]
// filterStrings(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == ["abc"]
func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap { value in
        if let stringValue = value as? String {
            return stringValue
        } else if let arrayValue = value as? [AnyHashable] {
            return filterStrings(values: arrayValue)
        } else if let dictValue = value as? [AnyHashable : AnyHashable] {
            return filterStrings(values: Array(dictValue.values))
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for dictionaries
// filterDictionaries(values: ["a", 3.14, 5]) == []
// filterDictionaries(values: [1, 2, 3, "abc", [:], []]) == [[:]]
func filterDictionaries(values: [AnyHashable]) -> [AnyHashable : AnyHashable] {
    return values.compactMap { value in
        if let dictValue = value as? [AnyHashable : AnyHashable] {
            return dictValue
        } else if let arrayValue = value as? [AnyHashable] {
            return filterDictionaries(values: arrayValue)
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for arrays
// filterArrays(values: ["a", 3.14, 5]) == []
// filterArrays(values: [1, 2, 3, "abc", [:], []]) == [[], [1, 2, 3, "abc", [:], []]]
func filterArrays(values: [AnyHashable]) -> [[AnyHashable]] {
    return values.compactMap { value in
        if let arrayValue = value as? [AnyHashable] {
            return arrayValue
        } else if let dictValue = value as? [AnyHashable : AnyHashable] {
            return filterArrays(values: Array(dictValue.values))
        }
        return nil
    }
}

// Flatten given array of any swiftthon values
// flatten(values: ["a", 3.14, 5, [1, 2, 3, "abc", [:], []]]) == ["a", 3.14, 5, 1, 2, 3, "abc", [:], []]
func flatten(values: [AnyHashable]) -> [AnyHashable] {
    var result: [AnyHashable] = []
    for value in values {
        if let arrayValue = value as? [AnyHashable] {
            result += flatten(values: arrayValue)
        } else {
            result.append(value)
        }
    }
    return result
}

// Return a new array of given array of any swiftthon values
// array(values: ["a", 3.14, 5]) == ["a", 3.14, 5]
// array(values: [1, 2, 3, "abc", [:], []]) == [1, 2, 3, "abc", [:], []]
func array(values: [AnyHashable]) -> [AnyHashable] {
    return values
}

// Return a new dictionary of given array of any swiftthon values
// dictionary(values: ["a", 3.14, 5]) == [:a: 3.14, :b: 5]
// dictionary(values: [1, 2, 3, "abc", [:], []]) == [:0: 1, :1: 2, :2: 3, :3:

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap { value in
        if let stringValue = value as? String {
            return stringValue
        }
        return nil
    }
}

func filterDictionaries(values: [AnyHashable]) -> [AnyHashable : AnyHashable] {
    return values.compactMap { value in
        if let dictionaryValue = value as? [AnyHashable : AnyHashable] {
            return dictionaryValue
        }
        return nil
    }
}

func filterArrays(values: [AnyHashable]) -> [Any] {
    return values.compactMap { value in
        if let arrayValue = value as? [Any] {
            return arrayValue
        }
        return nil
    }
}

func filterNumbers(values: [AnyHashable]) -> [Double] {
    return values.compactMap { value in
        if let numberValue = value as? Double {
            return numberValue
        }
        return nil
    }
}

func filterBooleans(values: [AnyHashable]) -> [Bool] {
    return values.compactMap { value in
        if let booleanValue = value as? Bool {
            return booleanValue
        }
        return nil
    }
}

func filterData(values: [AnyHashable]) -> [Data] {
    return values.compactMap { value in
        if let dataValue = value as? Data {
            return dataValue
        }
        return nil
    }
}

func filterOptionalValues(values: [AnyHashable]) -> [AnyHashable] {
    return values.compactMap { value in
        return value
    }
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let intValue = value as? Int {
            return intValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for strings
// filterStrings(values: ["a", 3.14, 5]) == ["a"]
// filterStrings(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == ["abc"]
func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap { value in
        if let stringValue = value as? String {
            return stringValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for dictionaries
// filterDictionaries(values: ["a", 3.14, 5]) == []
// filterDictionaries(values: [1, 2, 3, "abc", [:], []]) == [:] as [AnyHashable : AnyHashable]
func filterDictionaries(values: [AnyHashable]) -> [AnyHashable : AnyHashable] {
    return values.compactMap { value in
        if let dictionaryValue = value as? [AnyHashable : AnyHashable] {
            return dictionaryValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for arrays
// filterArrays(values: ["a", 3.14, 5]) == []
// filterArrays(values: [1, 2, 3, "abc", [:], []]) == []
func filterArrays(values: [AnyHashable]) -> [Any] {
    return values.compactMap { value in
        if let arrayValue = value as? [Any] {
            return arrayValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for numbers
// filterNumbers(values: ["a", 3.14, 5]) == [3.14]
// filterNumbers(values: [1, 2, 3, "abc", [:], []]) == []
func filterNumbers(values: [AnyHashable]) -> [Double] {
    return values.compactMap { value in
        if let numberValue = value as? Double {
            return numberValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for booleans
// filterBooleans(values: ["a", 3.14, 5]) == []
// filterBooleans(values: [true, false, true]) == [true, false]
func filterBooleans(values: [AnyHashable]) -> [Bool] {
    return values.compactMap { value in
        if let booleanValue = value as? Bool {
            return booleanValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for data
// filterData(values: ["a", 3.14, 5]) == []
// filterData(values: [Data(bytes: [0x01, 0x02, 0x03])]) == [Data(bytes: [0x01, 0x02, 0x03])]
func filterData(values: [AnyHashable]) -> [Data] {
    return values.compactMap { value in
        if let dataValue = value as? Data {
            return dataValue
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for optional values
// filterOptionalValues(values: ["a", 3.14, 5]) == ["a", 3.14, 5]
// filterOptionalValues(values: [1, 2, 3, "abc", [:], nil]) == [1, 2, 3, "abc", [:]]
func filterOptionalValues(values: [AnyHashable]) -> [AnyHashable] {
    return values.compactMap { value in
        return value
    }
}

// Filter given array of any swiftthon values only for enums
// filterEnums(values: ["a", 3.14, 5]) == []
// filterEnums(values: [1, 2, 3, "abc", [:], nil]) == []
// filterEnums(values: [TestEnum.one, TestEnum.two, TestEnum.three]) == [TestEnum.one, TestEnum.two, TestEnum.three]
enum TestEnum: Int, Hashable {
   

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let value = value as? Int {
            return value
        }
        return nil
    }
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let value = value as? Int {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let value = value as? Int {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let value = value as? Int {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let value = value as? Int {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let value = value as? Int {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let value = value as? Int {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let value = value as? Int {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap { value in
        if let value = value as? Int {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let value = $0 as? Int {
            return value
        } else if let value = $0 as? String, Int(value)!= nil {
            return Int(value)!
        } else {
            return nil
        }
    }
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let value = $0 as? Int {
            return value
        } else if let value = $0 as? String, Int(value)!= nil {
            return Int(value)!
        } else {
            return nil
        }
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let value = $0 as? Int {
            return value
        } else if let value = $0 as? String, Int(value)!= nil {
            return Int(value)!
        } else {
            return nil
        }
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let value = $0 as? Int {
            return value
        } else if let value = $0 as? String, Int(value)!= nil {
            return Int(value)!
        } else {
            return nil
        }
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let value = $0 as? Int {
            return value
        } else if let value = $0 as? String, Int(value)!= nil {
            return Int(value)!
        } else {
            return nil
        }
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let value = $0 as? Int {
            return value
        } else if let value = $0 as? String, Int(value)!= nil {
            return Int(value)!
        } else {
            return nil
        }
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let value = $0 as? Int {
            return value
        } else if let value = $0 as? String, Int(value)!= nil {
            return Int(value)!
        } else {
            return nil
        }
    }
}

// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let

func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let value = $0 as? Int {
            return value
        }
        return nil
    }
}

func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap {
        if let value = $0 as? String {
            return value
        }
        return nil
    }
}

func filterDictionaries(values: [AnyHashable]) -> [Dictionary<AnyHashable, AnyHashable>] {
    return values.compactMap {
        if let value = $0 as? Dictionary<AnyHashable, AnyHashable> {
            return value
        }
        return nil
    }
}

func filterArrays(values: [AnyHashable]) -> [[AnyHashable]] {
    return values.compactMap {
        if let value = $0 as? [AnyHashable] {
            return value
        }
        return nil
    }
}

func filterSets(values: [AnyHashable]) -> [Set<AnyHashable>] {
    return values.compactMap {
        if let value = $0 as? Set<AnyHashable> {
            return value
        }
        return nil
    }
}

func filterTuples(values: [AnyHashable]) -> [(AnyHashable, AnyHashable)] {
    return values.compactMap {
        if let value = $0 as? (AnyHashable, AnyHashable) {
            return value
        }
        return nil
    }
}

func filterOptionalValues(values: [AnyHashable]) -> [AnyHashable] {
    return values.compactMap {
        return $0
    }
}

enum Color: String, Hashable {
    case Red, Green, Blue
}

func filterEnums(values: [AnyHashable]) -> [Color] {
    return values.compactMap {
        if let value = $0 as? Color {
            return value
        }
        return nil
    }
}

```swift
// Filter given array of any swiftthon values only for integers
// filterIntegers(values: ["a", 3.14, 5]) == [5]
// filterIntegers(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3]
func filterIntegers(values: [AnyHashable]) -> [Int] {
    return values.compactMap {
        if let value = $0 as? Int {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for strings
// filterStrings(values: ["a", 3.14, 5]) == ["a"]
// filterStrings(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == ["abc"]
func filterStrings(values: [AnyHashable]) -> [String] {
    return values.compactMap {
        if let value = $0 as? String {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for dictionaries
// filterDictionaries(values: ["a", 3.14, 5]) == []
// filterDictionaries(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [:]]) == [[:]]
func filterDictionaries(values: [AnyHashable]) -> [Dictionary<AnyHashable, AnyHashable>] {
    return values.compactMap {
        if let value = $0 as? Dictionary<AnyHashable, AnyHashable> {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for arrays
// filterArrays(values: ["a", 3.14, 5]) == []
// filterArrays(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [[], []]
func filterArrays(values: [AnyHashable]) -> [[AnyHashable]] {
    return values.compactMap {
        if let value = $0 as? [AnyHashable] {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for sets
// filterSets(values: ["a", 3.14, 5]) == []
// filterSets(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [[:]]
func filterSets(values: [AnyHashable]) -> [Set<AnyHashable>] {
    return values.compactMap {
        if let value = $0 as? Set<AnyHashable> {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for tuples
// filterTuples(values: ["a", 3.14, 5]) == []
// filterTuples(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == []
func filterTuples(values: [AnyHashable]) -> [(AnyHashable, AnyHashable)] {
    return values.compactMap {
        if let value = $0 as? (AnyHashable, AnyHashable) {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for optional values
// filterOptionalValues(values: ["a", 3.14, 5]) == ["a", 3.14, 5]
// filterOptionalValues(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == [1, 2, 3, "abc", [:], []]
func filterOptionalValues(values: [AnyHashable]) -> [AnyHashable] {
    return values.compactMap {
        return $0
    }
}

// Filter given array of any swiftthon values only for enums
// filterEnums(values: ["a", 3.14, 5]) == []
// filterEnums(values: [1, 2, 3, "abc", [:] as [AnyHashable : AnyHashable], [] as [AnyHashable]]) == []
// filterEnums(values: [Red, Green, Blue]) == [Red, Green, Blue]
enum Color: String, Hashable {
    case Red, Green, Blue
}

func filterEnums(values: [AnyHashable]) -> [Color] {
    return values.compactMap {
        if let value = $0 as? Color {
            return value
        }
        return nil
    }
}

// Filter given array of any swiftthon values only for

func strlen(string: String) -> Int {
    if string.isEmpty {
        return 0
    } else {
        return 1 + strlen(string: string.dropFirst())
    }
}

func sumArray(array: [Int]) -> Int {
    if array.isEmpty {
        return 0
    } else {
        return array.first! + sumArray(array: Array(array.dropFirst()))
    }
}

func factorial(number: Int) -> Int {
    if number == 0 {
        return 1
    } else {
        return number * factorial(number: number - 1)
    }
}

func fibonacci(number: Int) -> Int {
    if number == 0 {
        return 0
    } else if number == 1 {
        return 1
    } else {
        return fibonacci(number: number - 1) + fibonacci(number: number - 2)
    }
}

func sumFibs(number: Int) -> Int {
    if number <= 2 {
        return number
    } else {
        return fibonacci(number: number - 1) + sumFibs(number: number - 2)
    }
}

func sumMult3Or5(number: Int) -> Int {
    if number <= 0 {
        return 0
    } else if number % 3 == 0 && number % 5 == 0 {
        return number + sumMult3Or5(number: number - 1)
    } else if number % 3 == 0 {
        return number + sumMult3Or5(number: number - 1)
    } else if number % 5 == 0 {
        return number + sumMult3Or5(number: number - 1)
    } else {
        return sumMult3Or5(number: number - 1)
    }
}

func fibonacciRecursion(number: Int) -> Int {
    if number <= 1 {
        return number
    } else {
        return fibonacciRecursion(number: number - 1) + fibonacciRecursion(number: number - 2)
    }
}

func sumFibsRecursion(number: Int) -> Int {
    if number <= 2 {
        return number
    } else {
        return fibonacciRecursion(number: number - 1) + sumFibsRecursion(number: number - 2)
    }
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    if string.isEmpty {
        return 0
    } else {
        return 1 + strlen(string: string.dropFirst())
    }
}

// Return the sum of all the integers in the given array
// sumArray([1, 2, 3]) == 6
// sumArray([1, 2, 3, 4, 5]) == 15
func sumArray(array: [Int]) -> Int {
    if array.isEmpty {
        return 0
    } else {
        return array.first! + sumArray(array: Array(array.dropFirst()))
    }
}

// Return the factorial of the given integer
// factorial(0) == 1
// factorial(5) == 120
func factorial(number: Int) -> Int {
    if number == 0 {
        return 1
    } else {
        return number * factorial(number: number - 1)
    }
}

// Return the nth fibonacci number
// fibonacci(0) == 0
// fibonacci(1) == 1
// fibonacci(5) == 5
func fibonacci(number: Int) -> Int {
    if number == 0 {
        return 0
    } else if number == 1 {
        return 1
    } else {
        return fibonacci(number: number - 1) + fibonacci(number: number - 2)
    }
}

// Return the sum of all the even fibonacci numbers less than or equal to the given integer
// sumFibs(10) == 10
// sumFibs(14) == 14
func sumFibs(number: Int) -> Int {
    if number <= 2 {
        return number
    } else {
        return fibonacci(number: number - 1) + sumFibs(number: number - 2)
    }
}

// Return the sum of all the multiples of 3 or 5 below the given integer
// sumMult3Or5(10) == 23
// sumMult3Or5(1000) == 233168
func sumMult3Or5(number: Int) -> Int {
    if number <= 0 {
        return 0
    } else if number % 3 == 0 && number % 5 == 0 {
        return number + sumMult3Or5(number: number - 1)
    } else if number % 3 == 0 {
        return number + sumMult3Or5(number: number - 1)
    } else if number % 5 == 0 {
        return number + sumMult3Or5(number: number - 1)
    } else {
        return sumMult3Or5(number: number - 1)
    }
}

// Return the nth Fibonacci number using recursion
// fibonacciRecursion(0) == 0
// fibonacciRecursion(1) == 1
// fibonacciRecursion(5) == 5
func fibonacciRecursion(number: Int) -> Int {
    if number <= 1 {
        return number
    } else {
        return fibonacciRecursion(number: number - 1) + fibonacciRecursion(number: number - 2)
    }
}

// Return the sum of all the even fibonacci numbers less than or equal to the given integer
// using recursion
// sumFibsRecursion(10) == 10
// sumFibsRecursion(14) == 14
func sumFibsRecursion(number: Int) -> Int {
    if number <= 2 {
        return number
    } else {
        return fibonacciRecursion(number: number - 1) + sumFibsRecursion(number: number - 2)
    }
}

// Return the sum of all the multiples of 3 or 5 below the given integer
// using recursion
// sumMult3Or5Recursion(10) == 23
// sumMult3Or5Recursion(1000) == 233168
func sumMult3Or5Recursion(number: Int) -> Int {
    if number <= 0 {
        return 0
    } else if number % 3 == 0 && number % 5 == 0 {
        return number + sumMult3Or5Recursion(number: number - 1)
    } else if number %

func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

func ucfirst(string: String) -> String {
    guard!string.isEmpty else { return "" }
    return string.prefix(1).uppercased() + string.dropFirst()
}

func nospace(string: String) -> String {
    return string.replacingOccurrences(of: " ", with: "")
}

func nopunc(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.punctuationCharacters)
}

func lowercase(string: String) -> String {
    return string.lowercased()
}

func uppercase(string: String) -> String {
    return string.uppercased()
}

func reversewords(string: String) -> String {
    return string.components(separatedBy: " ").map(String.init).reversed().joined(separator: " ")
}

func ucwords(string: String) -> String {
    return string.components(separatedBy: " ").map(ucfirst).joined(separator: " ")
}

func nochars(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
}

func printable(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines.union(CharacterSet.controlCharacters))
}

func ascii(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.nonASCIICharacters)
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

// Return reversed string
// reverse(string: "") == ""
// reverse(string: "abc") == "cba"
func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

// Return string with first character as upper case
// ucfirst(string: "") == ""
// ucfirst(string: "abc") == "Abc"
func ucfirst(string: String) -> String {
    guard!string.isEmpty else { return "" }
    return string.prefix(1).uppercased() + string.dropFirst()
}

// Return string with all spaces removed
// nospace(string: "abc def") == "abcdef"
// nospace(string: "abc  def") == "abcdef"
// nospace(string: "abc\tdef") == "abcdef"
// nospace(string: "abc\ndef") == "abcdef"
func nospace(string: String) -> String {
    return string.replacingOccurrences(of: " ", with: "")
}

// Return string with all punctuation marks removed
// nopunc(string: "Hello, world!") == "Hello world"
// nopunc(string: "Hello world") == "Hello world"
// nopunc(string: "Hello-world") == "Hello-world"
func nopunc(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.punctuationCharacters)
}

// Return string with all letters converted to lowercase
// lowercase(string: "Hello World") == "hello world"
func lowercase(string: String) -> String {
    return string.lowercased()
}

// Return string with all letters converted to uppercase
// uppercase(string: "Hello World") == "HELLO WORLD"
func uppercase(string: String) -> String {
    return string.uppercased()
}

// Return string with words reversed
// reversewords(string: "Hello World") == "World Hello"
// reversewords(string: "Hello   World") == "World Hello"
// reversewords(string: "Hello\nWorld") == "World Hello"
func reversewords(string: String) -> String {
    return string.components(separatedBy: " ").map(String.init).reversed().joined(separator: " ")
}

// Return string with first character of each word upper cased
// ucwords(string: "hello world") == "Hello World"
// ucwords(string: "hello   world") == "Hello   World"
func ucwords(string: String) -> String {
    return string.components(separatedBy: " ").map(ucfirst).joined(separator: " ")
}

// Return string with all special characters removed
// nochars(string: "Hello, world!") == "Hello world"
// nochars(string: "Hello world") == "Hello world"
// nochars(string: "Hello-world") == "Hello-world"
func nochars(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
}

// Return string with all non-printable characters removed
// printable(string: "\n\tHello, world!\n\t") == "Hello, world!"
// printable(string: "Hello, world!") == "Hello, world!"
// printable(string: "\n\t") == ""
func printable(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines.union(CharacterSet.controlCharacters))
}

// Return string with all non-ASCII characters removed
// ascii(string: "Hello, world!") == "Hello, world!"
// ascii(string: "Hello, 世界!") == "Hello, 世界!"
func ascii(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.nonASCIICharacters)
}

// Return string with all HTML tags removed
// html(string: "<b>Hello, world!</b>") == "Hello, world!"
// html(string: "Hello, <b>world!</b>") == "Hello, world!"
func html(string: String) -> String {
    return string.replacingOccurrences(of: "<[^>]*

func strlen(string: String) -> Int {
    return 0
}

func sum(array: [Int]) -> Int {
    return 0
}

func uniqueValues(array: [Int]) -> Int {
    return 0
}

func reverse(string: String) -> String {
    return ""
}

func permutations(string: String) -> [String] {
    return []
}

func combinations(array: [Int]) -> [[Int]] {
    return []
}

func isSorted(array: [Int]) -> Bool {
    return true
}

func containsDuplicates(array: [Int]) -> Bool {
    return false
}

func pairs(array: [Int], sum: Int) -> [(Int, Int)] {
    return []
}

func zeroSumPairs(array: [Int]) -> [(Int, Int)] {
    return []
}

func subarrays(array: [Int]) -> [[Int]] {
    return []
}

func isPalindrome(array: [Int]) -> Bool {
    return true
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    return 0
}

// Return sum of all numbers in given array
// sum(array: []) == 0
// sum(array: [1, 2, 3]) == 6
func sum(array: [Int]) -> Int {
    return 0
}

// Return count of all unique values in given array
// uniqueValues(array: []) == 0
// uniqueValues(array: [1, 2, 3, 1, 2, 3]) == 3
func uniqueValues(array: [Int]) -> Int {
    return 0
}

// Return reversed string
// reverse(string: "") == ""
// reverse(string: "abc") == "cba"
func reverse(string: String) -> String {
    return ""
}

// Return array of all permutations of given string
// permutations(string: "") == [""]
// permutations(string: "abc") == ["abc", "acb", "bac", "bca", "cab", "cba"]
func permutations(string: String) -> [String] {
    return []
}

// Return array of all combinations of given array
// combinations(array: []) == [[]]
// combinations(array: [1, 2, 3]) == [[1], [2], [3], [1, 2], [1, 3], [2, 3], [1, 2, 3]]
func combinations(array: [Int]) -> [[Int]] {
    return []
}

// Return true if given array is sorted in ascending order
// isSorted(array: []) == true
// isSorted(array: [1]) == true
// isSorted(array: [1, 2, 3]) == true
// isSorted(array: [3, 2, 1]) == false
func isSorted(array: [Int]) -> Bool {
    return true
}

// Return true if given array contains duplicates
// containsDuplicates(array: []) == false
// containsDuplicates(array: [1]) == false
// containsDuplicates(array: [1, 2, 3]) == false
// containsDuplicates(array: [1, 2, 2, 3]) == true
func containsDuplicates(array: [Int]) -> Bool {
    return false
}

// Return array of all pairs of elements that sum to given value
// pairs(array: [], sum: 10) == []
// pairs(array: [1, 2, 3, 4], sum: 6) == [(1, 5), (2, 4)]
// pairs(array: [1, 2, 3, 4], sum: 7) == [(1, 6), (2, 5), (3, 4)]
func pairs(array: [Int], sum: Int) -> [(Int, Int)] {
    return []
}

// Return array of all pairs of elements that sum to zero from given array
// zeroSumPairs(array: []) == []
// zeroSumPairs(array: [1, 2, 3, 4]) == [(1, 4), (2, 3)]
// zeroSumPairs(array: [1, 2, 3, 4, 5]) == [(1, 5), (2, 4), (3, 3)]
func zeroSumPairs(array: [Int]) -> [(Int, Int)] {
    return []
}

// Return array of all subarrays of given array
// subarrays(array: []) == [[]]
// subarrays(array: [1]) == [[1]]
// subarrays(array: [1, 2, 3]) == [[1], [2], [3], [1, 2], [2, 3], [1, 2, 3]]
func subarrays(array: [Int]) -> [[Int]] {
    return []
}

// Return true if given array is a palindrome
// isPalindrome(array: []) == true
// isPalindrome(array: [1]) == true
// isPalindrome(array: [1, 2, 3, 2, 1]) == true
// isPalindrome(array: [1, 2, 3, 4, 5]) == false
func isPalindrome(array: [Int]) -> Bool {
    return true
}

// Return true if given array is a permutation of a palind

func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

func ucfirst(string: String) -> String {
    guard!string.isEmpty else { return "" }
    return string.prefix(1).uppercased() + string.dropFirst()
}

func nospace(string: String) -> String {
    return string.replacingOccurrences(of: " ", with: "")
}

func nonalpha(string: String) -> String {
    return string.filter {!Character.isLetter($0) }
}

func nondigit(string: String) -> String {
    return string.filter {!Character.isNumber($0) }
}

func nonalnum(string: String) -> String {
    return string.filter {!Character.isLetterOrDigit($0) }
}

func compact(string: String) -> String {
    return string.trimmingCharacters(in:.whitespacesAndNewlines)
}

func compact(string: String, preserveNewlines: Bool) -> String {
    if preserveNewlines {
        return string.trimmingCharacters(in:.whitespacesAndNewlines)
    } else {
        return string.trimmingCharacters(in:.whitespaces)
    }
}

func remove(string: String, character: Character) -> String {
    var result = ""
    for char in string {
        if char!= character {
            result.append(char)
        }
    }
    return result
}

func whitelist(string: String, whitelist: String) -> String {
    var result = ""
    for char in string {
        if whitelist.contains(char) {
            result.append(char)
        }
    }
    return result
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

// Return reversed string
// reverse(string: "") == ""
// reverse(string: "abc") == "cba"
func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

// Return string with first character as upper case
// ucfirst(string: "") == ""
// ucfirst(string: "abc") == "Abc"
func ucfirst(string: String) -> String {
    guard!string.isEmpty else { return "" }
    return string.prefix(1).uppercased() + string.dropFirst()
}

// Return string with all spaces removed
// nospace(string: "abc def") == "abcdef"
// nospace(string: "abc  def") == "abcdef"
// nospace(string: "abc\tdef") == "abcdef"
func nospace(string: String) -> String {
    return string.replacingOccurrences(of: " ", with: "")
}

// Return string with all characters except alphabets removed
// nonalpha(string: "abc def") == "  def"
// nonalpha(string: "abc123 def") == "123 def"
// nonalpha(string: "abc!@#$% def") == "!@#$% def"
func nonalpha(string: String) -> String {
    return string.filter {!Character.isLetter($0) }
}

// Return string with all characters except digits removed
// nondigit(string: "abc123 def") == "abc def"
// nondigit(string: "abc!@#$% def") == "abc!@#$% def"
func nondigit(string: String) -> String {
    return string.filter {!Character.isNumber($0) }
}

// Return string with all characters except alphabets and digits removed
// nonalnum(string: "abc123 def") == "  def"
// nonalnum(string: "abc!@#$% def") == "!@#$% def"
func nonalnum(string: String) -> String {
    return string.filter {!Character.isLetterOrDigit($0) }
}

// Return string with all consecutive spaces removed
// compact(string: "abc  def") == "abc def"
// compact(string: "abc   def") == "abc def"
// compact(string: "abc\t def") == "abc def"
func compact(string: String) -> String {
    return string.trimmingCharacters(in:.whitespacesAndNewlines)
}

// Return string with all consecutive spaces and newlines removed
// compact(string: "abc\n def\n\n") == "abc def"
func compact(string: String, preserveNewlines: Bool) -> String {
    if preserveNewlines {
        return string.trimmingCharacters(in:.whitespacesAndNewlines)
    } else {
        return string.trimmingCharacters(in:.whitespaces)
    }
}

// Return string with all occurrences of character c removed
// remove(string: "abc def", character: "d") == "abc def"
// remove(string: "abc def", character: "e") == "abc d"
func remove(string: String, character: Character) -> String {
    var result = ""
    for char in string {
        if char!= character {
            result.append(char)
        }
    }
    return result
}

// Return string with all characters except those in the whitelist removed
// whitelist(string: "abc def", whitelist: "abc") == "def"
// whitelist(string: "abc def", whitelist: "abc def") == "abc def"
// whitelist(string: "abc def", whitelist: "abc", " ") == " def"
func whitelist(string: String, whitelist: String) -> String {
    var result = ""
    for char in string {
        if whitelist.contains(char) {
            result.append(char)
        }
    }
    return result
}

// Return string with all characters in the whitelist replaced by the corresponding character in the map
// whitelist(string: "abc def", whitelist: "abc", map: ["d": "x", "e": "x"])

func strlen(string: String) -> Int {
    if string.isEmpty {
        return 0
    } else {
        return 1 + strlen(string: string.dropFirst())
    }
}

func sum(n: Int) -> Int {
    if n == 0 {
        return 0
    } else {
        return n + sum(n: n - 1)
    }
}

func factorial(n: Int) -> Int {
    if n == 0 {
        return 1
    } else {
        return n * factorial(n: n - 1)
    }
}

func fibonacci(n: Int) -> Int {
    if n == 0 {
        return 0
    } else if n == 1 {
        return 1
    } else {
        return fibonacci(n: n - 1) + fibonacci(n: n - 2)
    }
}

func prime(n: Int) -> Int {
    if n == 0 {
        return 2
    } else {
        var i = 3
        while i < 100000 {
            if isPrime(i) {
                n += 1
                if n == 1 {
                    return i
                }
            }
            i += 2
        }
    }
    return 0
}

func isPrime(_ n: Int) -> Bool {
    if n < 2 {
        return false
    } else {
        var i = 2
        while i * i <= n {
            if n % i == 0 {
                return false
            }
            i += 1
        }
        return true
    }
}

func reverse(_ string: String) -> String {
    if string.isEmpty {
        return ""
    } else {
        return reverse(string.dropLast()) + string.first!
    }
}

func fibonacciDynamic(_ n: Int) -> Int {
    var fib = [Int]()
    fib.append(0)
    fib.append(1)
    for i in 2...n {
        fib.append(fib[i - 1] + fib[i - 2])
    }
    return fib[n]
}

func primeDynamic(_ n: Int) -> Int {
    var prime = [Int]()
    prime.append(2)
    var i = 3
    while prime.count < n {
        if isPrime(i) {
            prime.append(i)
        }
        i += 2
    }
    return prime[n - 1]
}

func isPalindrome(_ n: Int) -> Bool {
    return String(n) == String(String(n).reversed())
}

func sumSquares(_ n: Int) -> Int {
    if n == 0 {
        return 0
    } else {
        return n * (n + 1) * (2 * n + 1) / 6
    }
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    if string.isEmpty {
        return 0
    } else {
        return 1 + strlen(string: string.dropFirst())
    }
}

// Return sum of first n natural numbers
// sum(n: 0) == 0
// sum(n: 1) == 1
// sum(n: 5) == 15
func sum(n: Int) -> Int {
    if n == 0 {
        return 0
    } else {
        return n + sum(n: n - 1)
    }
}

// Return the factorial of a given number
// factorial(0) == 1
// factorial(5) == 120
func factorial(n: Int) -> Int {
    if n == 0 {
        return 1
    } else {
        return n * factorial(n: n - 1)
    }
}

// Return the nth fibonacci number
// fibonacci(0) == 0
// fibonacci(1) == 1
// fibonacci(5) == 5
func fibonacci(n: Int) -> Int {
    if n == 0 {
        return 0
    } else if n == 1 {
        return 1
    } else {
        return fibonacci(n: n - 1) + fibonacci(n: n - 2)
    }
}

// Return the nth prime number
// prime(0) == 2
// prime(1) == 3
// prime(5) == 11
func prime(n: Int) -> Int {
    if n == 0 {
        return 2
    } else {
        var i = 3
        while i < 100000 {
            if isPrime(i) {
                n += 1
                if n == 1 {
                    return i
                }
            }
            i += 2
        }
    }
    return 0
}

// Check if a given number is prime
func isPrime(_ n: Int) -> Bool {
    if n < 2 {
        return false
    } else {
        var i = 2
        while i * i <= n {
            if n % i == 0 {
                return false
            }
            i += 1
        }
        return true
    }
}

// Reverse a given string
// reverse("") == ""
// reverse("abc") == "cba"
func reverse(_ string: String) -> String {
    if string.isEmpty {
        return ""
    } else {
        return reverse(string.dropLast()) + string.first!
    }
}

// Return the nth Fibonacci number using dynamic programming
// fibonacciDynamic(0) == 0
// fibonacciDynamic(1) == 1
// fibonacciDynamic(5) == 5
func fibonacciDynamic(_ n: Int) -> Int {
    var fib = [Int]()
    fib.append(0)
    fib.append(1)
    for i in 2...n {
        fib.append(fib[i - 1] + fib[i - 2])
    }
    return fib[n]
}

// Return the nth prime number using dynamic programming
// primeDynamic(0) == 2
// primeDynamic(1) == 3
// primeDynamic(5) == 11
func primeDynamic(_ n: Int) -> Int {
    var prime = [Int]()
    prime.append(2)
    var i = 3
    while prime.count < n {
        if isPrime(i) {
            prime.append(i)
        }
        i += 2
    }
    return prime[n - 1]
}

// Check if a given number is palindrome
// isPalindrome(121) == true
// isPalindrome(123) == false
func isPalindrome(_ n: Int) -> Bool {
    return String(n) == String(String(n).reversed())
}

// Return the sum of squares of first n natural numbers
// sumSquares(0) == 0
// sumSquares(3) == 14
func sumSquares(_ n: Int) -> Int {
    if n == 0 {
        return 0
    } else {
        return n * (n + 1) * (2 * n + 1) / 6
    }
}

// Return the sum of cubes of first n natural numbers
// sumCubes(0) == 0
//

func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

func isPalindrome(string: String) -> Bool {
    if string == "" {
        return true
    }
    if string.count == 1 {
        return true
    }
    if string.count == 2 {
        return string[0] == string[1]
    }
    if string[0] == string.last! {
        return isPalindrome(string: String(string.suffix(from: 1)))
    }
    return false
}

func upper(string: String) -> String {
    var upperString = ""
    for char in string {
        upperString += "\(char.uppercased())"
    }
    return upperString
}

func lower(string: String) -> String {
    var lowerString = ""
    for char in string {
        lowerString += "\(char.lowercased())"
    }
    return lowerString
}

func capitalize(string: String) -> String {
    var capitalizedString = ""
    for (index, char) in string.enumerated() {
        if index == 0 {
            capitalizedString += "\(char.uppercased())"
        } else {
            capitalizedString += "\(char.lowercased())"
        }
    }
    return capitalizedString
}

func dropFirst(string: String) -> String {
    return String(string.suffix(from: 1))
}

func dropLast(string: String) -> String {
    return String(string.prefix(upTo: string.count - 1))
}

func chop(string: String) -> String {
    return String(string.suffix(from: 1).prefix(upTo: string.count - 2))
}

func chomp(string: String) -> String {
    if string.hasSuffix("\n") {
        return String(string.suffix(from: 1).prefix(upTo: string.count - 2))
    } else {
        return String(string.suffix(from: 1))
    }
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

// Return reversed string
// reverse(string: "") == ""
// reverse(string: "abc") == "cba"
func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

// Return true if string is palindrome
// isPalindrome(string: "") == true
// isPalindrome(string: "a") == true
// isPalindrome(string: "ab") == false
// isPalindrome(string: "abc") == true
// isPalindrome(string: "abcba") == true
// isPalindrome(string: "abacdfgdcaba") == true
func isPalindrome(string: String) -> Bool {
    if string == "" {
        return true
    }
    if string.count == 1 {
        return true
    }
    if string.count == 2 {
        return string[0] == string[1]
    }
    if string[0] == string.last! {
        return isPalindrome(string: String(string.suffix(from: 1)))
    }
    return false
}

// Return uppercase string
// upper(string: "") == ""
// upper(string: "abc") == "ABC"
// upper(string: "abc def") == "ABC DEF"
func upper(string: String) -> String {
    var upperString = ""
    for char in string {
        upperString += "\(char.uppercased())"
    }
    return upperString
}

// Return lowercase string
// lower(string: "") == ""
// lower(string: "ABC") == "abc"
// lower(string: "ABC DEF") == "abc def"
func lower(string: String) -> String {
    var lowerString = ""
    for char in string {
        lowerString += "\(char.lowercased())"
    }
    return lowerString
}

// Return string with first character capitalized
// capitalize(string: "") == ""
// capitalize(string: "abc") == "Abc"
// capitalize(string: "abc def") == "Abc def"
func capitalize(string: String) -> String {
    var capitalizedString = ""
    for (index, char) in string.enumerated() {
        if index == 0 {
            capitalizedString += "\(char.uppercased())"
        } else {
            capitalizedString += "\(char.lowercased())"
        }
    }
    return capitalizedString
}

// Return string with all characters but first removed
// dropFirst(string: "") == ""
// dropFirst(string: "abc") == "bc"
// dropFirst(string: "abc def") == " def"
func dropFirst(string: String) -> String {
    return String(string.suffix(from: 1))
}

// Return string with all characters but last removed
// dropLast(string: "") == ""
// dropLast(string: "abc") == "abc"
// dropLast(string: "abc def") == "abc "
func dropLast(string: String) -> String {
    return String(string.prefix(upTo: string.count - 1))
}

// Return string with all characters but first and last removed
// chop(string: "") == ""
// chop(string: "abc") == "bc"
// chop(string: "abc def") == " def"
func chop(string: String) -> String {
    return String(string.suffix(from: 1).prefix(upTo: string.count - 2))
}

// Return string with all characters but first and last removed
// chomp(string: "") == ""
// chomp(string: "abc") == "abc"
// chomp(string: "abc\n") == "abc"
// chomp(string: "abc\n\n") == "abc\n"
func chomp(string: String) -> String {
    if string.hasSuffix("\n") {
        return String(string.suffix(from: 1).prefix(upTo: string.count - 2))
    } else {
        return String(string.suffix(from: 1))
    }
}

// Return string with all characters but first and last removed
// chomp(string: "") == ""
// chomp(string: "abc") == "

func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

func upper(string: String) -> String {
    var upperString = ""
    for char in string {
        upperString += "\(char.uppercased())"
    }
    return upperString
}

func lower(string: String) -> String {
    var lowerString = ""
    for char in string {
        lowerString += "\(char.lowercased())"
    }
    return lowerString
}

func ucfirst(string: String) -> String {
    var firstChar = ""
    for char in string {
        firstChar = "\(char)"
        break
    }
    return firstChar.uppercased() + lower(string: string.dropFirst())
}

func substring(string: String, start: Int, end: Int) -> String {
    var substring = ""
    var count = 0
    for char in string {
        if count >= start && count <= end {
            substring += "\(char)"
        }
        count += 1
    }
    return substring
}

func after(string: String, character: Character) -> String {
    var afterString = ""
    var found = false
    for char in string {
        if char == character &&!found {
            found = true
        } else if found {
            afterString += "\(char)"
        }
    }
    return afterString
}

func before(string: String, character: Character) -> String {
    var beforeString = ""
    var found = false
    for char in string {
        if char == character &&!found {
            found = true
        } else {
            beforeString += "\(char)"
        }
    }
    return beforeString
}

func between(string: String, start: Character, end: Character) -> String {
    var betweenString = ""
    var foundStart = false
    var foundEnd = false
    for char in string {
        if char == start &&!foundStart {
            foundStart = true
        } else if char == end && foundStart &&!foundEnd {
            foundEnd = true
        } else if foundStart &&!foundEnd {
            betweenString += "\(char)"
        }
    }
    return betweenString
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

// Return reversed string
// reverse(string: "") == ""
// reverse(string: "abc") == "cba"
func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

// Return uppercase string
// upper(string: "") == ""
// upper(string: "abc") == "ABC"
func upper(string: String) -> String {
    var upperString = ""
    for char in string {
        upperString += "\(char.uppercased())"
    }
    return upperString
}

// Return lowercase string
// lower(string: "") == ""
// lower(string: "ABC") == "abc"
func lower(string: String) -> String {
    var lowerString = ""
    for char in string {
        lowerString += "\(char.lowercased())"
    }
    return lowerString
}

// Return string with first character as upper case
// ucfirst(string: "") == ""
// ucfirst(string: "abc") == "Abc"
func ucfirst(string: String) -> String {
    var firstChar = ""
    for char in string {
        firstChar = "\(char)"
        break
    }
    return firstChar.uppercased() + lower(string: string.dropFirst())
}

// Return substring from start to end (inclusive)
// substring(string: "", start: 0, end: 0) == ""
// substring(string: "abc", start: 0, end: 0) == ""
// substring(string: "abc", start: 0, end: 1) == "a"
// substring(string: "abc", start: 0, end: 2) == "ab"
// substring(string: "abc", start: 1, end: 2) == "bc"
func substring(string: String, start: Int, end: Int) -> String {
    var substring = ""
    var count = 0
    for char in string {
        if count >= start && count <= end {
            substring += "\(char)"
        }
        count += 1
    }
    return substring
}

// Return substring after first occurrence of character
// after(string: "", character: "") == ""
// after(string: "abc", character: "a") == "bc"
// after(string: "abc", character: "b") == ""
func after(string: String, character: Character) -> String {
    var afterString = ""
    var found = false
    for char in string {
        if char == character &&!found {
            found = true
        } else if found {
            afterString += "\(char)"
        }
    }
    return afterString
}

// Return substring before first occurrence of character
// before(string: "", character: "") == ""
// before(string: "abc", character: "c") == "ab"
// before(string: "abc", character: "b") == "a"
func before(string: String, character: Character) -> String {
    var beforeString = ""
    var found = false
    for char in string {
        if char == character &&!found {
            found = true
        } else {
            beforeString += "\(char)"
        }
    }
    return beforeString
}

// Return substring between two characters
// between(string: "", start: "", end: "") == ""
// between(string: "abc", start: "a", end: "c") == "b"
// between(string: "abc", start: "b", end: "a") == ""
func between(string: String, start: Character, end: Character) -> String {
    var betweenString = ""
    var foundStart = false
    var foundEnd = false
    for char in string {
        if char == start &&!foundStart {
            foundStart = true
        } else if char == end && foundStart &&!foundEnd {
            foundEnd = true
        } else if foundStart &&!foundEnd {
            betweenString += "\(char)"
        }
    }
    return betweenString
}

// Return string with all special characters removed
// noSpecial(string: "") == ""
// noSpecial(string: "abc123") == "abc123"
// noSpecial(string: "abc!@#$%") == "abc123"
func noSpecial(string: String

func strlen(string: String) -> Int {
    var length = 0
    for _ in string {
        length += 1
    }
    return length
}

func sumascii(string: String) -> Int {
    var sum = 0
    for char in string {
        sum += Int(char.asciiValue!)
    }
    return sum
}

func sumasciiexcludingvowels(string: String) -> Int {
    var sum = 0
    for char in string {
        if!"aeiouAEIOU".contains(char) {
            sum += Int(char.asciiValue!)
        }
    }
    return sum
}

func sumofascii(string: String) -> (Int, Int) {
    var evenSum = 0
    var oddSum = 0
    for (index, char) in string.characters.enumerate() {
        if index % 2 == 0 {
            evenSum += Int(char.asciiValue!)
        } else {
            oddSum += Int(char.asciiValue!)
        }
    }
    return (evenSum, oddSum)
}

func concat(str1: String, str2: String) -> String {
    return str1 + str2
}

func firstcharremoved(string: String) -> String {
    return String(string.characters.dropFirst())
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    var length = 0
    for _ in string {
        length += 1
    }
    return length
}

// Return the sum of the ASCII values of all characters in the given string
// sumascii(string: "") == 0
// sumascii(string: "abc") == 97 + 98 + 99 = 306
func sumascii(string: String) -> Int {
    var sum = 0
    for char in string {
        sum += Int(char.asciiValue!)
    }
    return sum
}

// Return the sum of the ASCII values of all characters in the given string, excluding any vowels
// sumasciiexcludingvowels(string: "") == 0
// sumasciiexcludingvowels(string: "abc") == 97 + 98 + 99 = 306
// sumasciiexcludingvowels(string: "aeiou") == 0
// sumasciiexcludingvowels(string: "bcdef") == 98 + 99 + 100 = 306
func sumasciiexcludingvowels(string: String) -> Int {
    var sum = 0
    for char in string {
        if!"aeiouAEIOU".contains(char) {
            sum += Int(char.asciiValue!)
        }
    }
    return sum
}

// Return the sum of the ASCII values of all even-indexed characters in the given string,
// and the sum of the ASCII values of all odd-indexed characters in the given string.
// The input string will always contain a minimum of 1 character, and a maximum of 50 characters.
// sumofascii(string: "") == (0, 0)
// sumofascii(string: "abc") == (97, 98, 99)
// sumofascii(string: "abcdef") == (97, 98, 99, 100, 101)
func sumofascii(string: String) -> (Int, Int) {
    var evenSum = 0
    var oddSum = 0
    for (index, char) in string.characters.enumerate() {
        if index % 2 == 0 {
            evenSum += Int(char.asciiValue!)
        } else {
            oddSum += Int(char.asciiValue!)
        }
    }
    return (evenSum, oddSum)
}

// Return the concatenation of the first string with the second string,
// the first string and the second string concatenated together,
// and the length of the first string concatenated with the length of the second string.
// concat(str1: "", str2: "") == ""
// concat(str1: "a", str2: "") == "a"
// concat(str1: "ab", str2: "cd") == "abcd"
// concat(str1: "abc", str2: "def") == "abcdef"
// concat(str1: "ab", str2: "cd") == "abcd"
// concat(str1: "abc", str2: "def") == "abcdef"
// concat(str1: "abc", str2: "def") == "abcdef"
// concat(str1: "abc", str2: "def") == "abcdef"
// concat(str1: "abcdef", str2: "ghijklmnop") == "abcdefghijklmnop"
// concat(str1: "abc", str2: "defghijklmnop") == "abcdefghijklmnop"
// concat(str1: "abcdefghijklmnop", str2: "qrstuvwxyz") == "abcdefghijklmnopqrstuvwxyz"
func concat(str1: String, str2: String) -> String {
    return str1 + str2
}

// Return the string with the first character removed
// firstcharremoved(string: "") == ""
// firstcharremoved(string: "a") == ""
// firstcharremoved(string: "abc") == "bc"
// firstcharremoved(string: "abcdef") == "def"
func firstcharremoved(string: String) -> String {
    return String(string.characters.dropFirst())
}

// Return the string with the last character removed
// lastcharremoved(string: "") == ""
// lastcharremoved(string: "a") == ""
// lastcharremoved(string: "abc") == "ab"
// lastcharremoved(string: "

func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

func ucfirst(string: String) -> String {
    guard!string.isEmpty else { return "" }
    return string.prefix(1).uppercased() + string.dropFirst()
}

func nospace(string: String) -> String {
    return string.replacingOccurrences(of: " ", with: "")
}

func nopunc(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.punctuationCharacters)
}

func reversewords(string: String) -> String {
    return string.components(separatedBy: " ").map(reverse).joined(separator: " ")
}

func isalpha(string: String) -> Bool {
    for char in string {
        if!CharacterSet.alphabetic.contains(char) {
            return false
        }
    }
    return true
}

func isalnum(string: String) -> Bool {
    for char in string {
        if!CharacterSet.alphanumerics.contains(char) {
            return false
        }
    }
    return true
}

func isdigit(string: String) -> Bool {
    for char in string {
        if!CharacterSet.decimalDigits.contains(char) {
            return false
        }
    }
    return true
}

func isxdigit(string: String) -> Bool {
    for char in string {
        if!CharacterSet.hexadecimalDigits.contains(char) {
            return false
        }
    }
    return true
}

func isupper(string: String) -> Bool {
    for char in string {
        if!CharacterSet.uppercaseLetters.contains(char) {
            return false
        }
    }
    return true
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    var count = 0
    for _ in string {
        count += 1
    }
    return count
}

// Return reversed string
// reverse(string: "") == ""
// reverse(string: "abc") == "cba"
func reverse(string: String) -> String {
    var reversed = ""
    for char in string {
        reversed = "\(char)" + reversed
    }
    return reversed
}

// Return string with first character as upper case
// ucfirst(string: "") == ""
// ucfirst(string: "abc") == "Abc"
func ucfirst(string: String) -> String {
    guard!string.isEmpty else { return "" }
    return string.prefix(1).uppercased() + string.dropFirst()
}

// Return string with all spaces removed
// nospace(string: "abc def") == "abcdef"
// nospace(string: "abc  def") == "abcdef"
// nospace(string: "abc\tdef") == "abcdef"
func nospace(string: String) -> String {
    return string.replacingOccurrences(of: " ", with: "")
}

// Return string with all punctuation marks removed
// nopunc(string: "Hello, world!") == "Hello world"
// nopunc(string: "Hello world") == "Hello world"
// nopunc(string: "Hello-world") == "Hello-world"
func nopunc(string: String) -> String {
    return string.trimmingCharacters(in: CharacterSet.punctuationCharacters)
}

// Return string with words reversed
// reversewords(string: "Hello world") == "dlrow olleH"
// reversewords(string: "Hello") == "olleH"
// reversewords(string: "Hello world, how are you?") == "you? are how world Hello"
func reversewords(string: String) -> String {
    return string.components(separatedBy: " ").map(reverse).joined(separator: " ")
}

// Return true if string contains only alphabetic characters
// isalpha(string: "abc") == true
// isalpha(string: "abc123") == false
func isalpha(string: String) -> Bool {
    for char in string {
        if!CharacterSet.alphabetic.contains(char) {
            return false
        }
    }
    return true
}

// Return true if string contains only alphanumeric characters
// isalnum(string: "abc123") == true
// isalnum(string: "abc123!") == false
func isalnum(string: String) -> Bool {
    for char in string {
        if!CharacterSet.alphanumerics.contains(char) {
            return false
        }
    }
    return true
}

// Return true if string contains only digits
// isdigit(string: "123") == true
// isdigit(string: "abc123") == false
func isdigit(string: String) -> Bool {
    for char in string {
        if!CharacterSet.decimalDigits.contains(char) {
            return false
        }
    }
    return true
}

// Return true if string contains only hexadecimal characters
// isxdigit(string: "abc123") == false
// isxdigit(string: "abcdef") == false
// isxdigit(string: "ABC123") == false
// isxdigit(string: "ABCDEF") == false
// isxdigit(string: "abcdefABCDEF0123") == true
func isxdigit(string: String) -> Bool {
    for char in string {
        if!CharacterSet.hexadecimalDigits.contains(char) {
            return false
        }
    }
    return true
}

// Return true if string contains only uppercase alphabetic characters
// isupper(string: "ABC") == true
// isupper(string: "abc") == false
func isupper(string: String) -> Bool {
    for char in string {
        if!CharacterSet.uppercaseLetters.contains(char) {
            return false
        }
    }
    return true
}

// Return true if string contains only lowercase alphabetic characters
// islower(string: "abc") == true
// islower(string: "ABC") == false
func islower(string: String) -> Bool {
    for char in string {
        if!CharacterSet.lowercaseLetters.contains(char) {
            return false
        }
    }
    return true

func strlen(string: String) -> Int {
    if string.isEmpty {
        return 0
    } else {
        return 1 + strlen(string: string.dropFirst())
    }
}

func sum(n: Int) -> Int {
    if n == 0 {
        return 0
    } else {
        return n + sum(n: n - 1)
    }
}

func factorial(n: Int) -> Int {
    if n == 0 {
        return 1
    } else {
        return n * factorial(n: n - 1)
    }
}

func fib(n: Int) -> Int {
    if n == 0 {
        return 0
    } else if n == 1 {
        return 1
    } else {
        return fib(n: n - 1) + fib(n: n - 2)
    }
}

func product(string: String) -> String {
    if string.count == 1 {
        return string
    } else {
        return string.prefix(1) + product(string: string.dropFirst())
    }
}

func sum_of_squares(n: Int) -> Int {
    if n == 1 {
        return 1
    } else {
        return n * n + sum_of_squares(n: n - 1)
    }
}

func square_of_sum(n: Int) -> Int {
    return sum(n: n) * sum(n: n)
}

func difference(n: Int) -> Int {
    return square_of_sum(n: n) - sum_of_squares(n: n)
}

func is_palindrome(number: Int) -> Bool {
    if number < 10 {
        return true
    } else {
        let lastDigit = number % 10
        let firstDigit = number / 10
        return lastDigit == firstDigit && is_palindrome(number: number / 10)
    }
}

func digits(number: Int) -> Int {
    if number < 10 {
        return 1
    } else {
        return 1 + digits(number: number / 10)
    }
}

func cubes_sum(n: Int) -> Int {
    if n == 1 {
        return 1
    } else {
        return n * n * n + cubes_sum(n: n - 1)
    }
}

```swift
// Return length of given string
// strlen(string: "") == 0
// strlen(string: "abc") == 3
func strlen(string: String) -> Int {
    if string.isEmpty {
        return 0
    } else {
        return 1 + strlen(string: string.dropFirst())
    }
}

// Return the sum of the first n integers
// sum(n: 0) == 0
// sum(n: 1) == 1
// sum(n: 5) == 15
func sum(n: Int) -> Int {
    if n == 0 {
        return 0
    } else {
        return n + sum(n: n - 1)
    }
}

// Return the factorial of a given number
// factorial(0) == 1
// factorial(5) == 120
func factorial(n: Int) -> Int {
    if n == 0 {
        return 1
    } else {
        return n * factorial(n: n - 1)
    }
}

// Return the nth fibonacci number
// fib(0) == 0
// fib(1) == 1
// fib(5) == 5
func fib(n: Int) -> Int {
    if n == 0 {
        return 0
    } else if n == 1 {
        return 1
    } else {
        return fib(n: n - 1) + fib(n: n - 2)
    }
}

// Return the product of a given string
// product("abc") == "a"
// product("abcd") == "ab"
// product("abcde") == "abcde"
func product(string: String) -> String {
    if string.count == 1 {
        return string
    } else {
        return string.prefix(1) + product(string: string.dropFirst())
    }
}

// Return the sum of squares of first n natural numbers
// sum_of_squares(1) == 1
// sum_of_squares(5) == 55
func sum_of_squares(n: Int) -> Int {
    if n == 1 {
        return 1
    } else {
        return n * n + sum_of_squares(n: n - 1)
    }
}

// Return the square of sum of first n natural numbers
// square_of_sum(1) == 1
// square_of_sum(5) == 225
func square_of_sum(n: Int) -> Int {
    return sum(n: n) * sum(n: n)
}

// Return the difference between sum_of_squares and square_of_sum of first n natural numbers
// difference(1) == 0
// difference(5) == 2640
func difference(n: Int) -> Int {
    return square_of_sum(n: n) - sum_of_squares(n: n)
}

// Return true if a given number is a palindrome
// is_palindrome(121) == true
// is_palindrome(123) == false
func is_palindrome(number: Int) -> Bool {
    if number < 10 {
        return true
    } else {
        let lastDigit = number % 10
        let firstDigit = number / 10
        return lastDigit == firstDigit && is_palindrome(number: number / 10)
    }
}

// Return the number of digits in a given number
// digits(1234) == 4
// digits(123) == 3
func digits(number: Int) -> Int {
    if number < 10 {
        return 1
    } else {
        return 1 + digits(number: number / 10)
    }
}

// Return the sum of the cubes of all positive integers from 1 to n
// cubes_sum(1) == 1
// cubes_sum(5) == 125
func cubes_sum(n: Int) -> Int {
    if n == 1 {
        return 1
    } else {
        return n * n * n + cubes_sum(n: n - 1)
    }
}

// Return the sum of the squares of all positive integers from 1 to n
// squares_sum(1) == 1
// squares_sum(5) == 55
func squares_sum(n: Int) -> Int {
    if n == 1 {
        return 1
    } else {
        return n * n

func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            n = n / i
        } else {
            i += 1
        }
    }
    return i
}

func smallestMultiple(n: Int) -> Int {
    var i = 2
    var multiple = 1
    while i <= n {
        multiple *= i
        i += 1
    }
    return multiple
}

func fibonacciSum(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

func fibonacciSum2(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

func fibonacciSum3(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

func fibonacciSum4(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

func fibonacciSum5(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

func fibonacciSum6(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

func fibonacciSum7(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            n = n / i
        } else {
            i += 1
        }
    }
    return i
}

// For a given number n, find the smallest number that is evenly divisible by all numbers from 1 to n
// smallestMultiple(n: 10) == 2520
func smallestMultiple(n: Int) -> Int {
    var i = 2
    var multiple = 1
    while i <= n {
        multiple *= i
        i += 1
    }
    return multiple
}

// Find the sum of all even Fibonacci numbers less than or equal to 1000
// fibonacciSum(1000) == 1433455
func fibonacciSum(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

// Find the sum of all even Fibonacci numbers less than or equal to 4 million
// fibonacciSum(4000000) == 4613732
func fibonacciSum2(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

// Find the sum of all even Fibonacci numbers less than or equal to 4 million
// fibonacciSum(4000000) == 4613732
func fibonacciSum3(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

// Find the sum of all even Fibonacci numbers less than or equal to 4 million
// fibonacciSum(4000000) == 4613732
func fibonacciSum4(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

// Find the sum of all even Fibonacci numbers less than or equal to 4 million
// fibonacciSum(4000000) == 4613732
func fibonacciSum5(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

// Find the sum of all even Fibonacci numbers less than or equal to 4 million
// fibonacciSum(4000000) == 4613732
func fibonacciSum6(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

// Find the sum of all even Fibonacci numbers less than or equal to 4 million
// fibonacciSum(4000000) == 4613732
func fibonacciSum7(limit: Int) -> Int {
    var a = 1
    var b = 2
    var sum = 2
    while b < limit {
        let temp = b
        b = a + b
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

func largestDivisor(n: Int) -> Int {
    var largest = 1
    while largest * largest <= n {
        if n % largest == 0 {
            return largest
        }
        largest += 1
    }
    return n
}

func smallestCommons(_ arr: [Int]) -> Int {
    let sortedArr = arr.sorted()
    var largest = sortedArr[sortedArr.count - 1]
    var smallestCommons = largest
    while true {
        var isDivisible = true
        for i in 0..<sortedArr.count - 1 {
            if smallestCommons % sortedArr[i]!= 0 {
                isDivisible = false
                break
            }
        }
        if isDivisible {
            return smallestCommons
        }
        smallestCommons += largest
    }
}

func nextSmallestCommons(_ n: Int) -> Int {
    var i = n + 1
    while true {
        var isDivisible = true
        for j in 2...i {
            if i % j!= 0 {
                isDivisible = false
                break
            }
        }
        if isDivisible {
            return i
        }
        i += 1
    }
}

func nextLargestCommons(_ n: Int) -> Int {
    var i = n + 1
    while true {
        var isDivisible = true
        for j in 2...i {
            if i % j!= 0 {
                isDivisible = false
                break
            }
        }
        if isDivisible {
            return i
        }
        i += 1
    }
}

func numDivisors(_ n: Int) -> Int {
    var count = 0
    for i in 1...n {
        if n % i == 0 {
            count += 1
        }
    }
    return count
}

func sumDivisors(_ n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if n % i == 0 {
            sum += i
        }
    }
    return sum
}

func sumDivisorsExcludingPrime(_ n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if n % i == 0 &&!isPrime(i) {
            sum += i
        }
    }
    return sum
}

func sumDivisorsExcludingPerfectSquare(_ n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if n % i == 0 &&!isPerfectSquare(i) {
            sum += i
        }
    }
    return sum
}

func sumDivisorsExcludingMultipleOf3And5(_ n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if n % i == 0 && (i % 3!= 0 || i % 5!= 0) {
            sum += i
        }
    }
    return sum
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    var largest = 1
    while largest * largest <= n {
        if n % largest == 0 {
            return largest
        }
        largest += 1
    }
    return n
}

// For a given number n, find the smallest number that is evenly divisible by all numbers from 1 to n
// smallestCommons([1, 2, 3, 4, 5]) == 60
func smallestCommons(_ arr: [Int]) -> Int {
    let sortedArr = arr.sorted()
    var largest = sortedArr[sortedArr.count - 1]
    var smallestCommons = largest
    while true {
        var isDivisible = true
        for i in 0..<sortedArr.count - 1 {
            if smallestCommons % sortedArr[i]!= 0 {
                isDivisible = false
                break
            }
        }
        if isDivisible {
            return smallestCommons
        }
        smallestCommons += largest
    }
}

// For a given number n, find the next smallest number that is evenly divisible by all numbers from 1 to n
// nextSmallestCommons(15) == 30
func nextSmallestCommons(_ n: Int) -> Int {
    var i = n + 1
    while true {
        var isDivisible = true
        for j in 2...i {
            if i % j!= 0 {
                isDivisible = false
                break
            }
        }
        if isDivisible {
            return i
        }
        i += 1
    }
}

// For a given number n, find the next largest number that is evenly divisible by all numbers from 1 to n
// nextLargestCommons(15) == 60
func nextLargestCommons(_ n: Int) -> Int {
    var i = n + 1
    while true {
        var isDivisible = true
        for j in 2...i {
            if i % j!= 0 {
                isDivisible = false
                break
            }
        }
        if isDivisible {
            return i
        }
        i += 1
    }
}

// For a given number n, find the number of divisors that n has
// numDivisors(12) == 3
func numDivisors(_ n: Int) -> Int {
    var count = 0
    for i in 1...n {
        if n % i == 0 {
            count += 1
        }
    }
    return count
}

// Find the sum of all the divisors that n has
// sumDivisors(12) == 16
func sumDivisors(_ n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if n % i == 0 {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the divisors that n has, excluding prime numbers
// sumDivisorsExcludingPrime(12) == 15
func sumDivisorsExcludingPrime(_ n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if n % i == 0 &&!isPrime(i) {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the divisors that n has, excluding perfect squares
// sumDivisorsExcludingPerfectSquare(12) == 10
func sumDivisorsExcludingPerfectSquare(_ n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if n % i == 0 &&!isPerfectSquare(i) {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the divisors that n has, excluding numbers that are divisible by both 3 and 5
// sumDivisorsExcludingMultipleOf3And5(12) == 8
func sumDivisorsExcludingMultipleOf3And5(_ n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if n % i == 0 && (i % 3!= 0 || i % 5!= 0) {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the divisors that n has, excluding numbers that are divisible by 7 and 11
// sumDivisorsExcludingMultipleOf7And11(12) == 

func largestDivisor(n: Int) -> Int {
    var largest = 1
    while largest * largest <= n {
        if n % largest == 0 {
            return largest
        }
        largest += 1
    }
    return n
}

func smallestCommons(_ arr: [Int]) -> Int {
    let sortedArr = arr.sorted()
    var largest = sortedArr[sortedArr.count - 1]
    var smallest = sortedArr[0]
    var commons = largest
    while true {
        for i in 1...sortedArr.count - 1 {
            if commons % sortedArr[i]!= 0 {
                break
            } else if i == sortedArr.count - 1 {
                return commons
            }
        }
        commons += largest
    }
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    var largest = 1
    while largest * largest <= n {
        if n % largest == 0 {
            return largest
        }
        largest += 1
    }
    return n
}

// For a given number n, find the smallest number that is evenly divisible by all numbers from 1 to n
// smallestCommons([1, 5]) == 60
func smallestCommons(_ arr: [Int]) -> Int {
    let sortedArr = arr.sorted()
    var largest = sortedArr[sortedArr.count - 1]
    var smallest = sortedArr[0]
    var commons = largest
    while true {
        for i in 1...sortedArr.count - 1 {
            if commons % sortedArr[i]!= 0 {
                break
            } else if i == sortedArr.count - 1 {
                return commons
            }
        }
        commons += largest
    }
}

print(largestDivisor(n: 15))
print(smallestCommons([1, 5]))

func largestDivisor(n: Int) -> Int {
    // TODO: Implement the function according to the suggested steps in the output, including the time and space complexity analysis
    return 0
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    // TODO: Implement the function according to the suggested steps in the output, including the time and space complexity analysis
    return 0
}

// Examples:
assert(largestDivisor(n: 15) == 5)
assert(largestDivisor(n: 6) == 3)
assert(largestDivisor(n: 24) == 6)
assert(largestDivisor(n: 7) == 7)
assert(largestDivisor(n: 21) == 7)
assert(largestDivisor(n: 999) == 333)
assert(largestDivisor(n: 1000) == 333)
assert(largestDivisor(n: 10000) == 3333)
assert(largestDivisor(n: 100000) == 33333)
assert(largestDivisor(n: 1000000) == 333333)
assert(largestDivisor(n: 10000000) == 3333333)
assert(largestDivisor(n: 100000000) == 33333333)
assert(largestDivisor(n: 1000000000) == 333333333)
```

func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            return i
        }
        i += 1
    }
    return 1
}

func smallestMult(n: Int) -> Int {
    var result = 1
    for i in 1...n {
        result *= largestDivisor(n: i)
    }
    return result
}

func nextPrime(n: Int) -> Int {
    var i = n + 1
    while true {
        if isPrime(n: i) {
            return i
        }
        i += 1
    }
}

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func primeFactors(n: Int) -> [Int: Int] {
    var result = [Int: Int]()
    var i = 2
    while i <= n {
        if n % i == 0 {
            if result[i] == nil {
                result[i] = 1
            } else {
                result[i]! += 1
            }
            n /= i
        } else {
            i += 1
        }
    }
    return result
}

func primeFactorization(n: Int) -> [Int: Int] {
    var result = [Int: Int]()
    var i = 2
    while i <= n {
        if n % i == 0 {
            if result[i] == nil {
                result[i] = 1
            } else {
                result[i]! += 1
            }
            n /= i
        } else {
            i += 1
        }
    }
    return result
}

func gcd(a: Int, _ b: Int) -> Int {
    var a = abs(a)
    var b = abs(b)
    while b!= 0 {
        let temp = b
        b = a % b
        a = temp
    }
    return a
}

func lcm(a: Int, _ b: Int) -> Int {
    return abs(a * b) / gcd(a: a, b: b)
}

func lcm(array: [Int]) -> Int {
    var result = array[0]
    for i in 1..<array.count {
        result = lcm(a: result, b: array[i])
    }
    return result
}

func digits(n: Int) -> Int {
    return String(n).count
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            return i
        }
        i += 1
    }
    return 1
}

// For a given number n, find the smallest number that is evenly divisible by all numbers from 1 to n
// smallestMult(n: 15) == 60
func smallestMult(n: Int) -> Int {
    var result = 1
    for i in 1...n {
        result *= largestDivisor(n: i)
    }
    return result
}

// For a given number n, find the next prime number after n
// nextPrime(n: 15) == 17
func nextPrime(n: Int) -> Int {
    var i = n + 1
    while true {
        if isPrime(n: i) {
            return i
        }
        i += 1
    }
}

// For a given number n, determine if it is prime
// isPrime(n: 15) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// For a given number n, determine the prime factors of n
// primeFactors(n: 15) == [3: 2, 5: 1]
func primeFactors(n: Int) -> [Int: Int] {
    var result = [Int: Int]()
    var i = 2
    while i <= n {
        if n % i == 0 {
            if result[i] == nil {
                result[i] = 1
            } else {
                result[i]! += 1
            }
            n /= i
        } else {
            i += 1
        }
    }
    return result
}

// For a given number n, determine the prime factors and their exponents
// primeFactorization(n: 15) == [3: 2, 5: 1]
func primeFactorization(n: Int) -> [Int: Int] {
    var result = [Int: Int]()
    var i = 2
    while i <= n {
        if n % i == 0 {
            if result[i] == nil {
                result[i] = 1
            } else {
                result[i]! += 1
            }
            n /= i
        } else {
            i += 1
        }
    }
    return result
}

// For a given number n, determine the prime factors and their exponents
// primeFactorization(n: 15) == [3: 2, 5: 1]
func primeFactorization(n: Int) -> [Int: Int] {
    var result = [Int: Int]()
    var i = 2
    while i <= n {
        if n % i == 0 {
            if result[i] == nil {
                result[i] = 1
            } else {
                result[i]! += 1
            }
            n /= i
        } else {
            i += 1
        }
    }
    return result
}

// Find the greatest common divisor of two numbers
// gcd(10, 15) == 5
func gcd(a: Int, _ b: Int) -> Int {
    var a = abs(a)
    var b = abs(b)
    while b!= 0 {
        let temp = b
        b = a % b
        a = temp
    }
    return a
}

// Find the least common multiple of two numbers
// lcm(10, 15) == 60
func lcm(a: Int, _ b: Int) -> Int {
    return abs(a * b) / gcd(a: a, b: b)
}

// Find the least common multiple of an array of numbers
// lcm([10, 15, 20]) == 600
func lcm(array: [Int]) -> Int {
    var result = array[0]
    for i in 1..<array.count {
        result = lcm(a: result, b: array[i])
    }
    return result
}

// Find the number of digits in a number
// digits(1234) == 4
func digits(n: Int) -> Int {
    return String(n).count
}

// Find the number of digits in a number
//

func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            return i
        }
        i += 1
    }
    return 1
}

func smallestCommons(_ arr: [Int]) -> Int {
    let range = arr.sorted()
    var i = range[0]
    while true {
        let isDivisible = arr.filter { i % $0 == 0 }.count == arr.count
        if isDivisible {
            return i
        }
        i += range[1] - range[0]
    }
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            return i
        }
        i += 1
    }
    return 1
}

// For a given number n, find the smallest number that is evenly divisible by all numbers from 1 to n
// smallestCommons([1, 5]) == 60
func smallestCommons(_ arr: [Int]) -> Int {
    let range = arr.sorted()
    var i = range[0]
    while true {
        let isDivisible = arr.filter { i % $0 == 0 }.count == arr.count
        if isDivisible {
            return i
        }
        i += range[1] - range[0]
    }
}

print(largestDivisor(n: 15))
print(smallestCommons([1, 5]))

func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            n = n / i
        } else {
            i += 1
        }
    }
    return i
}

func smallestCommons(_ arr: [Int]) -> Int {
    var max = arr.max()!
    var min = arr.min()!
    var range = max - min + 1
    var result = 1
    for i in 1...range {
        result *= i
    }
    for i in 1...max {
        if!isDivisible(result, i) {
            result = lcm(result, i)
        }
    }
    return result
}

func isDivisible(_ num: Int, _ divisor: Int) -> Bool {
    return num % divisor == 0
}

func gcd(_ a: Int, _ b: Int) -> Int {
    if b == 0 {
        return a
    }
    return gcd(b, a % b)
}

func lcm(_ a: Int, _ b: Int) -> Int {
    return a * b / gcd(a, b)
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            n = n / i
        } else {
            i += 1
        }
    }
    return i
}

// For a given number n, find the smallest number that is evenly divisible by all numbers from 1 to n
// smallestCommons([1, 3, 5]) == 60
func smallestCommons(_ arr: [Int]) -> Int {
    var max = arr.max()!
    var min = arr.min()!
    var range = max - min + 1
    var result = 1
    for i in 1...range {
        result *= i
    }
    for i in 1...max {
        if!isDivisible(result, i) {
            result = lcm(result, i)
        }
    }
    return result
}

func isDivisible(_ num: Int, _ divisor: Int) -> Bool {
    return num % divisor == 0
}

func gcd(_ a: Int, _ b: Int) -> Int {
    if b == 0 {
        return a
    }
    return gcd(b, a % b)
}

func lcm(_ a: Int, _ b: Int) -> Int {
    return a * b / gcd(a, b)
}

smallestCommons([1, 5])

func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            n /= i
        } else {
            i += 1
        }
    }
    return i
}

func smallestMult(n: Int) -> Int {
    var result = 1
    for i in 1...n {
        result *= i
    }
    return result
}

func sumMultiples(limit: Int) -> Int {
    var result = 0
    for i in 1...limit {
        if i % 3 == 0 || i % 5 == 0 {
            result += i
        }
    }
    return result
}

func sumFibs(limit: Int) -> Int {
    var result = 2
    var current = 1
    var previous = 1
    while current < limit {
        let next = current + previous
        previous = current
        current = next
        if current % 2 == 0 {
            result += current
        }
    }
    return result
}

func greatestProduct(input: Int) -> Int {
    var result = 0
    let str = String(input)
    for i in 100...str.count - 3 {
        for j in 100...str.count - 3 {
            let first = Int(String(str[i...i+2]))!
            let second = Int(String(str[j...j+2]))!
            if first * second > result {
                result = first * second
            }
        }
    }
    return result
}

func sumAmicable(limit: Int) -> Int {
    var result = 0
    for i in 2...limit {
        var sum1 = 0
        var j = 1
        while j < i {
            if i % j == 0 {
                sum1 += j
            }
            j += 1
        }
        var sum2 = 0
        var k = 1
        while k < sum1 {
            if sum1 % k == 0 {
                sum2 += k
            }
            k += 1
        }
        if sum2 == i && i!= sum1 {
            result += i
        }
    }
    return result
}

func sumAbundant(limit: Int) -> Int {
    var result = 0
    for i in 1...limit {
        if isAbundant(i) {
            result += i
        }
    }
    return result
}

func sumPowDigs(limit: Int) -> Int {
    var result = 0
    for i in 1...limit {
        if isPowDig(i) {
            result += i
        }
    }
    return result
}

func sumTo2020(limit: Int) -> Int {
    var result = 0
    for i in 1...limit {
        for j in 1...limit {
            if i + j == 2020 {
                result += 1
            }
        }
    }
    return result
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            n /= i
        } else {
            i += 1
        }
    }
    return i
}

// For a given number n, find the smallest number that is evenly divisible by all numbers from 1 to n
// smallestMult(n: 10) == 2520
func smallestMult(n: Int) -> Int {
    var result = 1
    for i in 1...n {
        result *= i
    }
    return result
}

// Find the sum of all the multiples of 3 or 5 below 1000
// sumMultiples(limit: 1000) == 233168
func sumMultiples(limit: Int) -> Int {
    var result = 0
    for i in 1...limit {
        if i % 3 == 0 || i % 5 == 0 {
            result += i
        }
    }
    return result
}

// Find the sum of all the even Fibonacci numbers below 4 million
// sumFibs(limit: 4_000_000) == 4613732
func sumFibs(limit: Int) -> Int {
    var result = 2
    var current = 1
    var previous = 1
    while current < limit {
        let next = current + previous
        previous = current
        current = next
        if current % 2 == 0 {
            result += current
        }
    }
    return result
}

// Find the greatest product of two three-digit numbers in the 1000-digit number
// greatestProduct(input: 130_000) == 23514624000
func greatestProduct(input: Int) -> Int {
    var result = 0
    let str = String(input)
    for i in 100...str.count - 3 {
        for j in 100...str.count - 3 {
            let first = Int(String(str[i...i+2]))!
            let second = Int(String(str[j...j+2]))!
            if first * second > result {
                result = first * second
            }
        }
    }
    return result
}

// Find the sum of all the amicable numbers under 10000
// sumAmicable(limit: 10_000) == 31626
func sumAmicable(limit: Int) -> Int {
    var result = 0
    for i in 2...limit {
        var sum1 = 0
        var j = 1
        while j < i {
            if i % j == 0 {
                sum1 += j
            }
            j += 1
        }
        var sum2 = 0
        var k = 1
        while k < sum1 {
            if sum1 % k == 0 {
                sum2 += k
            }
            k += 1
        }
        if sum2 == i && i!= sum1 {
            result += i
        }
    }
    return result
}

// Find the sum of all the abundant numbers under 28123
// sumAbundant(limit: 28123) == 4179871
func sumAbundant(limit: Int) -> Int {
    var result = 0
    for i in 1...limit {
        if isAbundant(i) {
            result += i
        }
    }
    return result
}

// Find the sum of all the numbers which can be written as the sum of fifth powers of their digits
// sumPowDigs(limit: 10000) == 37328
func sumPowDigs(limit: Int) -> Int {
    var result = 0
    for i in 1...limit {
        if isPowDig(i) {
            result += i
        }
    }
    return result
}

// Find the number of numbers between 1 and 1000 that add up to 2020
// sumTo2020(limit: 1000) == 241
func sumTo2020(limit: Int) -> Int {
    var result = 0
    for i in 1...limit {
        for j in 1...limit {
            if i + j == 2020 {
                result += 1
            }
        }
    }
    return result
}

//

func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            return i
        }
        i += 1
    }
    return 1
}

func smallestMult(n: Int) -> Int {
    var i = 1
    while true {
        var isDiv = true
        for j in 2...n {
            if i % j!= 0 {
                isDiv = false
                break
            }
        }
        if isDiv {
            return i
        }
        i *= 2
    }
}

func sumMultiples() -> Int {
    var sum = 0
    for i in 1...999 {
        if i % 3 == 0 || i % 5 == 0 {
            sum += i
        }
    }
    return sum
}

func sumFibs() -> Int {
    var sum = 2
    var a = 1
    var b = 2
    while b < 4_000_000 {
        let temp = b
        b += a
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

func largestProduct() -> Int {
    var max = 0
    let numString = getInputString()
    for i in 0...numString.count - 3 {
        for j in i+1...numString.count - 2 {
            let first = Int(String(numString[i...j]))!
            for k in j+1...numString.count - 1 {
                let second = Int(String(numString[j+1...k]))!
                let product = first * second
                if product > max {
                    max = product
                }
            }
        }
    }
    return max
}

func sumAmicable() -> Int {
    var sum = 0
    for i in 2...10_000 {
        if isSumOfProperDivisors(i) && isSumOfProperDivisors(i, sum: i) {
            sum += i
        }
    }
    return sum
}

func sumAbundant() -> Int {
    var sum = 0
    for i in 12...28123 {
        if isAbundant(i) {
            sum += i
        }
    }
    return sum
}

func smallestMult() -> Int {
    var num = 1
    for i in 2...20 {
        num *= smallestMult(i)
    }
    return num
}

func numDigits(n: Int) -> Int {
    var num = n
    var count = 0
    while num > 0 {
        num /= 10
        count += 1
    }
    return count
}

func largestPalindrome() -> Int {
    var max = 0
    for i in 100...999 {
        for j in 100...999 {
            let product = i * j
            if product > max && isPalindrome(product) {
                max = product
            }
        }
    }
    return max
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            return i
        }
        i += 1
    }
    return 1
}

// For a given number n, find the smallest number that is evenly divisible from 1 to n
// smallestMult(n: 15) == 60
func smallestMult(n: Int) -> Int {
    var i = 1
    while true {
        var isDiv = true
        for j in 2...n {
            if i % j!= 0 {
                isDiv = false
                break
            }
        }
        if isDiv {
            return i
        }
        i *= 2
    }
}

// Find the sum of all the multiples of 3 or 5 below 1000
// sumMultiples() == 233168
func sumMultiples() -> Int {
    var sum = 0
    for i in 1...999 {
        if i % 3 == 0 || i % 5 == 0 {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the even Fibonacci numbers below 4 million
// sumFibs() == 4613732
func sumFibs() -> Int {
    var sum = 2
    var a = 1
    var b = 2
    while b < 4_000_000 {
        let temp = b
        b += a
        a = temp
        if b % 2 == 0 {
            sum += b
        }
    }
    return sum
}

// Find the greatest product of two three-digit numbers in the 1000-digit number
// largestProduct() == 906609
func largestProduct() -> Int {
    var max = 0
    let numString = getInputString()
    for i in 0...numString.count - 3 {
        for j in i+1...numString.count - 2 {
            let first = Int(String(numString[i...j]))!
            for k in j+1...numString.count - 1 {
                let second = Int(String(numString[j+1...k]))!
                let product = first * second
                if product > max {
                    max = product
                }
            }
        }
    }
    return max
}

// Find the sum of all the amicable numbers under 10000
// sumAmicable() == 31626
func sumAmicable() -> Int {
    var sum = 0
    for i in 2...10_000 {
        if isSumOfProperDivisors(i) && isSumOfProperDivisors(i, sum: i) {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the abundant numbers under 28123
// sumAbundant() == 4179871
func sumAbundant() -> Int {
    var sum = 0
    for i in 12...28123 {
        if isAbundant(i) {
            sum += i
        }
    }
    return sum
}

// Find the smallest number divisible by all integers from 1 to 20
// smallestMult() == 232792560
func smallestMult() -> Int {
    var num = 1
    for i in 2...20 {
        num *= smallestMult(i)
    }
    return num
}

// Find the number of digits in the number 100!
// numDigits(100!) == 20
func numDigits(n: Int) -> Int {
    var num = n
    var count = 0
    while num > 0 {
        num /= 10
        count += 1
    }
    return count
}

// Find the greatest palindrome made from the product of two 3-digit numbers
// largestPalindrome() == 906609
func largestPalindrome() -> Int {
    var max = 0
    for i in 100...999 {
        for j in 100...999 {
            let product = i * j
            if product > max && isPalindrome(product) {
                max = product
            }
        }
    }
    return max
}

// Find the sum of all the amicable numbers under 10000
// sumDeficient() == 31

func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            return i
        }
        i += 1
    }
    return 1
}

func smallestCommons(_ arr: [Int]) -> Int {
    let max = arr.max()!
    var i = 1
    while true {
        let divisible = arr.filter { i % $0 == 0 }
        if divisible.count == arr.count {
            return i
        }
        i += max
    }
}

func sumMultiples() -> Int {
    var sum = 0
    for i in 1...1000 {
        if i % 7 == 0 || i % 13 == 0 {
            sum += i
        }
    }
    return sum
}

func sumAmicable() -> Int {
    var sum = 0
    for i in 2...10000 {
        let sumOfDivisors = divisors(i).reduce(0, +)
        let sumOfDivisorsOfSumOfDivisors = divisors(sumOfDivisors).reduce(0, +)
        if sumOfDivisors == i && sumOfDivisors!= sumOfDivisorsOfSumOfDivisors {
            sum += i
        }
    }
    return sum
}

func sumOfAbundant() -> Int {
    var sum = 0
    for i in 12...28123 {
        if isAbundant(i) {
            sum += i
        }
    }
    return sum
}

func sumOfDigitFifthPowers() -> Int {
    var sum = 0
    for i in 10...999 {
        let digits = Array(String(i))
        if digits.reduce(0, +).power(5) == i {
            sum += i
        }
    }
    return sum
}

func sumOfPerfectSquares() -> Int {
    var sum = 0
    for i in 1...1000 {
        if isPerfectSquare(i) {
            sum += i
        }
    }
    return sum
}

func sumOfDeficientSquares() -> Int {
    var sum = 0
    for i in 1...1000 {
        if isDeficientSquare(i) {
            sum += i
        }
    }
    return sum
}

func sumOfAbundantSquares() -> Int {
    var sum = 0
    for i in 1...1000 {
        if isAbundantSquare(i) {
            sum += i
        }
    }
    return sum
}

func sumOfSquares() -> Int {
    var sum = 0
    for i in 1...100 {
        sum += i * i
    }
    return sum
}

```swift
// For a given number n, find the largest number that divides n evenly, smaller than n
// largestDivisor(n: 15) == 5
func largestDivisor(n: Int) -> Int {
    var i = 2
    while i < n {
        if n % i == 0 {
            return i
        }
        i += 1
    }
    return 1
}

// For a given number n, find the smallest number that is evenly divisible by all numbers from 1 to n
// smallestCommons([1, 3, 5]) == 60
func smallestCommons(_ arr: [Int]) -> Int {
    let max = arr.max()!
    var i = 1
    while true {
        let divisible = arr.filter { i % $0 == 0 }
        if divisible.count == arr.count {
            return i
        }
        i += max
    }
}

// Find the sum of all the multiples of 7 or 13 below 1000
// sumMultiples() == 233168
func sumMultiples() -> Int {
    var sum = 0
    for i in 1...1000 {
        if i % 7 == 0 || i % 13 == 0 {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the amicable numbers under 10000
// sumAmicable() == 31626
func sumAmicable() -> Int {
    var sum = 0
    for i in 2...10000 {
        let sumOfDivisors = divisors(i).reduce(0, +)
        let sumOfDivisorsOfSumOfDivisors = divisors(sumOfDivisors).reduce(0, +)
        if sumOfDivisors == i && sumOfDivisors!= sumOfDivisorsOfSumOfDivisors {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the abundant numbers under 28123
// sumOfAbundant() == 4179871
func sumOfAbundant() -> Int {
    var sum = 0
    for i in 12...28123 {
        if isAbundant(i) {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the numbers which can be written as the sum of fifth powers of their digits
// sumOfDigitFifthPowers() == 373092176
func sumOfDigitFifthPowers() -> Int {
    var sum = 0
    for i in 10...999 {
        let digits = Array(String(i))
        if digits.reduce(0, +).power(5) == i {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the amicable numbers under 10000
// sumOfPerfectSquares() == 87218
func sumOfPerfectSquares() -> Int {
    var sum = 0
    for i in 1...1000 {
        if isPerfectSquare(i) {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the amicable numbers under 10000
// sumOfPerfectSquares() == 87218
func sumOfDeficientSquares() -> Int {
    var sum = 0
    for i in 1...1000 {
        if isDeficientSquare(i) {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the amicable numbers under 10000
// sumOfPerfectSquares() == 87218
func sumOfAbundantSquares() -> Int {
    var sum = 0
    for i in 1...1000 {
        if isAbundantSquare(i) {
            sum += i
        }
    }
    return sum
}

// Find the sum of all the amicable numbers under 10000
// sumOfPerfectSquares() == 87218
func sumOfSquares() -> Int {
    var sum = 0
    for i in 1...100 {
        sum += i * i
    }
    return sum
}

// Find the sum of all the amicable numbers under 10000
// sumOfPerfectSquares() == 87218
func sumOfCubes() -> Int {
    var sum = 0
    for i in 1...100 {
        sum

func factorize(n: Int) -> [Int] {
    var factors = [Int]()
    var divisor = 2
    while divisor <= n {
        if n % divisor == 0 {
            factors.append(divisor)
            n /= divisor
        } else {
            divisor += 1
        }
    }
    return factors
}

func sumOfDigits(n: Int) -> Int {
    var n = n
    var sum = 0
    while n > 0 {
        sum += n % 10
        n /= 10
    }
    return sum
}

func sumOfDigits2(n: Int) -> Int {
    return String(n).reduce(0, +)
}

func sumOfDigits3(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

func sumOfDigits4(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

func sumOfDigits5(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

func sumOfDigits6(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

func sumOfDigits7(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

func sumOfDigits8(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

func sumOfDigits9(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

func sumOfDigits10(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors = [Int]()
    var divisor = 2
    while divisor <= n {
        if n % divisor == 0 {
            factors.append(divisor)
            n /= divisor
        } else {
            divisor += 1
        }
    }
    return factors
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits(n: Int) -> Int {
    var n = n
    var sum = 0
    while n > 0 {
        sum += n % 10
        n /= 10
    }
    return sum
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits2(n: Int) -> Int {
    return String(n).reduce(0, +)
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits3(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits4(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits5(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits6(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits7(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits8(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits9(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOfDigits10(n: Int) -> Int {
    return String(n).map { Int(String($0))! }.reduce(0, +)
}

// Return the sum of all digits in the given integer.
// Input: 12345
// Output: 15
// Input: 987654321
// Output: 45
func sumOf

func factorize(n: Int) -> [Int] {
    var factors = [Int]()
    var number = n
    var divisor = 2

    while number > 1 {
        while number % divisor == 0 {
            factors.append(divisor)
            number /= divisor
        }
        divisor += 1
    }

    return factors
}

func sumDigits(n: Int) -> Int {
    var sum = 0
    var number = n

    while number > 0 {
        sum += number % 10
        number /= 10
    }

    return sum
}

func productDigits(n: Int) -> Int {
    var product = 1
    var number = n

    while number > 0 {
        product *= number % 10
        number /= 10
    }

    return product
}

func sumDigitsExceptThree(n: Int) -> Int {
    var sum = 0
    var number = n

    while number > 0 {
        let digit = number % 10
        if digit % 3!= 0 {
            sum += digit
        }
        number /= 10
    }

    return sum
}

func productDigitsExceptThree(n: Int) -> Int {
    var product = 1
    var number = n

    while number > 0 {
        let digit = number % 10
        if digit % 3!= 0 {
            product *= digit
        }
        number /= 10
    }

    return product
}

func sumDigitsExceptTwoFive(n: Int) -> Int {
    var sum = 0
    var number = n

    while number > 0 {
        let digit = number % 10
        if digit % 2!= 0 && digit % 5!= 0 {
            sum += digit
        }
        number /= 10
    }

    return sum
}

func productDigitsExceptTwoFive(n: Int) -> Int {
    var product = 1
    var number = n

    while number > 0 {
        let digit = number % 10
        if digit % 2!= 0 && digit % 5!= 0 {
            product *= digit
        }
        number /= 10
    }

    return product
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors = [Int]()
    var number = n
    var divisor = 2

    while number > 1 {
        while number % divisor == 0 {
            factors.append(divisor)
            number /= divisor
        }
        divisor += 1
    }

    return factors
}

// Return the sum of all digits in the given integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
// sumDigits(n: 1010) == 11
func sumDigits(n: Int) -> Int {
    var sum = 0
    var number = n

    while number > 0 {
        sum += number % 10
        number /= 10
    }

    return sum
}

// Return the product of all digits in the given integer
// productDigits(n: 123) == 6
// productDigits(n: 456) == 210
// productDigits(n: 1010) == 100
func productDigits(n: Int) -> Int {
    var product = 1
    var number = n

    while number > 0 {
        product *= number % 10
        number /= 10
    }

    return product
}

// Return the sum of all digits in the given integer, excluding any digits that are divisible by 3
// sumDigitsExceptThree(n: 123) == 3
// sumDigitsExceptThree(n: 456) == 6
// sumDigitsExceptThree(n: 1010) == 2
func sumDigitsExceptThree(n: Int) -> Int {
    var sum = 0
    var number = n

    while number > 0 {
        let digit = number % 10
        if digit % 3!= 0 {
            sum += digit
        }
        number /= 10
    }

    return sum
}

// Return the product of all digits in the given integer, excluding any digits that are divisible by 3
// productDigitsExceptThree(n: 123) == 1
// productDigitsExceptThree(n: 456) == 120
// productDigitsExceptThree(n: 1010) == 10
func productDigitsExceptThree(n: Int) -> Int {
    var product = 1
    var number = n

    while number > 0 {
        let digit = number % 10
        if digit % 3!= 0 {
            product *= digit
        }
        number /= 10
    }

    return product
}

// Return the sum of all digits in the given integer, excluding any digits that are divisible by 2 or 5
// sumDigitsExceptTwoFive(n: 123) == 3
// sumDigitsExceptTwoFive(n: 456) == 6
// sumDigitsExceptTwoFive(n: 1010) == 1
func sumDigitsExceptTwoFive(n: Int) -> Int {
    var sum = 0
    var number = n

    while number > 0 {
        let digit = number % 10
        if digit % 2!= 0 && digit % 5!= 0 {
            sum += digit
        }
        number /= 10
    }

    return sum
}

// Return the product of all digits in the given integer, excluding any digits that are divisible by 2 or 5
// productDigitsExceptTwoFive(n: 123) == 1
// productDigitsExceptTwoFive(n: 456) == 120
// productDigitsExceptTwoFive(n: 1010) == 10
func productDigitsExceptTwoFive(n: Int) -> Int {
    var product = 1
    var number = n

    while number > 0 {
        let digit = number % 10
        if digit % 2!= 0 && digit % 5!= 0 {
            product *= digit
        }
        number /= 10
    }

    return product
}

// Return the sum of all digits in the given integer, excluding any digits that are divisible by 7
// sumDigitsExceptSeven(n: 123) == 6
// sumDigitsExceptSeven(n: 456) == 15
// sumDigitsExceptSeven(n: 1010)

func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var number = n
    for i in 2...n {
        var count = 0
        while number % i == 0 {
            number /= i
            count += 1
        }
        if count > 0 {
            factors.append(i)
            factors.append(count)
        }
    }
    return factors
}

func greatestCommonDivisors(a: Int, b: Int) -> [Int] {
    var a = a
    var b = b
    var result: [Int] = []
    while b!= 0 {
        let remainder = a % b
        a = b
        b = remainder
    }
    let gcd = a
    var number = a <= b? a : b
    while number > 1 {
        if number % gcd == 0 {
            result.append(number)
        }
        number -= 1
    }
    return result
}

func sumArray(_ array: [Int]) -> Int {
    var result = 0
    for number in array {
        result += number
    }
    return result
}

func productArray(_ array: [Int]) -> Int {
    var result = 1
    for number in array {
        result *= number
    }
    return result
}

func difference(_ array: [Int]) -> Int {
    var min = array[0]
    var max = array[0]
    for number in array {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return max - min
}

func countElements(_ array: [Int]) -> Int {
    var sum = 0
    for number in array {
        sum += number
    }
    let average = sum / array.count
    var count = 0
    for number in array {
        if number > average {
            count += 1
        }
    }
    return count
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var number = n
    for i in 2...n {
        var count = 0
        while number % i == 0 {
            number /= i
            count += 1
        }
        if count > 0 {
            factors.append(i)
            factors.append(count)
        }
    }
    return factors
}

// Return array of all numbers between 2 given numbers that have a greatest common divisor (GCD) equal to 1.
// The array should be sorted in ascending order.
// Input numbers should be positive integers and 2 <= n <= 100
// Example:
// greatestCommonDivisors(a: 2, b: 16) == [1, 2, 4, 8, 16]
// greatestCommonDivisors(a: 7, b: 15) == [1, 7]
func greatestCommonDivisors(a: Int, b: Int) -> [Int] {
    var a = a
    var b = b
    var result: [Int] = []
    while b!= 0 {
        let remainder = a % b
        a = b
        b = remainder
    }
    let gcd = a
    var number = a <= b? a : b
    while number > 1 {
        if number % gcd == 0 {
            result.append(number)
        }
        number -= 1
    }
    return result
}

// Return the sum of all elements in the array.
// The array may contain negative numbers and duplicates
// Example:
// sumArray([1, 2, 3, 4, 5]) == 15
// sumArray([-1, 0, 1]) == 0
func sumArray(_ array: [Int]) -> Int {
    var result = 0
    for number in array {
        result += number
    }
    return result
}

// Return the product of all elements in the array.
// The array may contain negative numbers and duplicates
// Example:
// productArray([1, 2, 3, 4, 5]) == 120
// productArray([-1, 0, 1]) == 0
func productArray(_ array: [Int]) -> Int {
    var result = 1
    for number in array {
        result *= number
    }
    return result
}

// Return the difference between the largest and smallest elements in the array.
// The array may contain duplicate numbers
// Example:
// difference([1, 5, 2, 10, 3]) == 9
// difference([-1, 0, 1]) == 2
func difference(_ array: [Int]) -> Int {
    var min = array[0]
    var max = array[0]
    for number in array {
        if number > max {
            max = number
        }
        if number < min {
            min = number
        }
    }
    return max - min
}

// Return the number (count) of elements that are greater than the average value of the array.
// The array may contain negative numbers and duplicates
// Example:
// countElements([1, 2, 3, 4, 5]) == 3
// countElements([1, 1, 1, 4, 5]) == 4
// countElements([-1, 0, 1]) == 0
func countElements(_ array: [Int]) -> Int {
    var sum = 0
    for number in array {
        sum += number
    }
    let average = sum / array.count
    var count = 0
    for number in array {
        if number > average {
            count += 1
        }
    }
    return count
}

// Return the number (count) of elements that are greater than the average value of the array.
// The array may contain negative numbers and duplicates
// Example:
// countElements([1, 2, 3, 4, 5]) == 3
// countElements([1, 1, 1, 4, 5]) == 4
// countElements([-1, 0, 1]) == 0
func countElements(_ array: [Int]) -> Int {
    var sum = 0
    for number in array {
        sum += number
    }
    let average = sum / array.count
    var count = 0
    for number in array {
        if number > average {
            count += 1
        }
    }
    return count
}

// Return the number (count) of elements that are greater than the

func factorize(n: Int) -> [Int] {
    var factors: [Int: Int] = [:]
    var number = n
    for i in 2...n {
        while number % i == 0 {
            if factors[i] == nil {
                factors[i] = 1
            } else {
                factors[i]! += 1
            }
            number /= i
        }
    }
    return Array(factors.values)
}

func divideNumbers(dividend: Int, divisor: Int) -> [Int] {
    var numbers: [Int] = []
    var number = dividend
    while number >= divisor {
        numbers.append(number)
        number -= divisor
    }
    return numbers
}

func sumDivisibleNumbers(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

func sumDivisibleNumbers2(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

func sumDivisibleNumbers3(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

func sumDivisibleNumbers4(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

func sumDivisibleNumbers5(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

func sumDivisibleNumbers6(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

func sumDivisibleNumbers7(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors: [Int: Int] = [:]
    var number = n
    for i in 2...n {
        while number % i == 0 {
            if factors[i] == nil {
                factors[i] = 1
            } else {
                factors[i]! += 1
            }
            number /= i
        }
    }
    return Array(factors.values)
}

// Return array of all numbers between 2 given numbers (inclusive) which are divisible by given divisor.
// The numbers in the array should be sorted in ascending order.
// Inputs:
// - dividend: 2
// - divisor: 3
// - Output: [3, 6]
func divideNumbers(dividend: Int, divisor: Int) -> [Int] {
    var numbers: [Int] = []
    var number = dividend
    while number >= divisor {
        numbers.append(number)
        number -= divisor
    }
    return numbers
}

// Return the sum of all numbers between 2 given numbers (inclusive) which are divisible by given divisor.
// Inputs:
// - dividend: 2
// - divisor: 3
// - Output: 3 + 6 = 9
func sumDivisibleNumbers(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

// Return the sum of all numbers between 2 given numbers (inclusive) which are divisible by given divisor.
// Inputs:
// - dividend: 2
// - divisor: 3
// - Output: 3 + 6 = 9
func sumDivisibleNumbers2(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

// Return the sum of all numbers between 2 given numbers (inclusive) which are divisible by given divisor.
// Inputs:
// - dividend: 2
// - divisor: 3
// - Output: 3 + 6 = 9
func sumDivisibleNumbers3(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

// Return the sum of all numbers between 2 given numbers (inclusive) which are divisible by given divisor.
// Inputs:
// - dividend: 2
// - divisor: 3
// - Output: 3 + 6 = 9
func sumDivisibleNumbers4(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

// Return the sum of all numbers between 2 given numbers (inclusive) which are divisible by given divisor.
// Inputs:
// - dividend: 2
// - divisor: 3
// - Output: 3 + 6 = 9
func sumDivisibleNumbers5(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

// Return the sum of all numbers between 2 given numbers (inclusive) which are divisible by given divisor.
// Inputs:
// - dividend: 2
// - divisor: 3
// - Output: 3 + 6 = 9
func sumDivisibleNumbers6(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

// Return the sum of all numbers between 2 given numbers (inclusive) which are divisible by given divisor.
// Inputs:
// - dividend: 2
// - divisor: 3
// - Output: 3 + 6 = 9
func sumDivisibleNumbers7(dividend: Int, divisor: Int) -> Int {
    return divideNumbers(dividend: dividend, divisor: divisor).reduce(0, +)
}

// Return the sum of all numbers between 2 given numbers (inclusive) which are divisible by given div

func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var divisor = 2
    while divisor <= n {
        if n % divisor == 0 {
            factors.append(divisor)
            n /= divisor
        } else {
            divisor += 1
        }
    }
    return factors
}

func sumDigits(n: Int) -> Int {
    var sum = 0
    var n = n
    while n > 0 {
        sum += n % 10
        n /= 10
    }
    return sum
}

func sumDivisibleDigits(n: Int) -> Int {
    var sum = 0
    var n = n
    while n > 0 {
        let digit = n % 10
        if digit % 3!= 0 {
            sum += digit
        }
        n /= 10
    }
    return sum
}

func productDigits(n: Int) -> Int {
    var product = 1
    var n = n
    while n > 0 {
        product *= n % 10
        n /= 10
    }
    return product
}

func productDivisibleDigits(n: Int) -> Int {
    var product = 1
    var n = n
    while n > 0 {
        let digit = n % 10
        if digit % 3!= 0 {
            product *= digit
        }
        n /= 10
    }
    return product
}

func digitsCount(n: Int) -> Int {
    var count = 0
    var n = n
    while n > 0 {
        count += 1
        n /= 10
    }
    return count
}

func sumDivisibleDigitsNotDivisibleBy3And2(n: Int) -> Int {
    var sum = 0
    var n = n
    while n > 0 {
        let digit = n % 10
        if digit % 3!= 0 && digit % 2!= 0 {
            sum += digit
        }
        n /= 10
    }
    return sum
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var divisor = 2
    while divisor <= n {
        if n % divisor == 0 {
            factors.append(divisor)
            n /= divisor
        } else {
            divisor += 1
        }
    }
    return factors
}

// Return the sum of all digits in the given integer.
// Input number should be positive
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
// sumDigits(n: 789) == 24
func sumDigits(n: Int) -> Int {
    var sum = 0
    var n = n
    while n > 0 {
        sum += n % 10
        n /= 10
    }
    return sum
}

// Return the sum of all digits in the given integer, excluding any digits that are divisible by 3.
// Input number should be positive
// sumDivisibleDigits(n: 123) == 6
// sumDivisibleDigits(n: 456) == 15
// sumDivisibleDigits(n: 789) == 24
func sumDivisibleDigits(n: Int) -> Int {
    var sum = 0
    var n = n
    while n > 0 {
        let digit = n % 10
        if digit % 3!= 0 {
            sum += digit
        }
        n /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number should be positive
// productDigits(n: 123) == 6
// productDigits(n: 456) == 216
// productDigits(n: 789) == 576
func productDigits(n: Int) -> Int {
    var product = 1
    var n = n
    while n > 0 {
        product *= n % 10
        n /= 10
    }
    return product
}

// Return the product of all digits in the given integer, excluding any digits that are divisible by 3.
// Input number should be positive
// productDivisibleDigits(n: 123) == 6
// productDivisibleDigits(n: 456) == 216
// productDivisibleDigits(n: 789) == 576
func productDivisibleDigits(n: Int) -> Int {
    var product = 1
    var n = n
    while n > 0 {
        let digit = n % 10
        if digit % 3!= 0 {
            product *= digit
        }
        n /= 10
    }
    return product
}

// Return the number of digits in the given integer.
// Input number should be positive
// digitsCount(n: 123) == 3
// digitsCount(n: 456) == 3
// digitsCount(n: 789) == 3
func digitsCount(n: Int) -> Int {
    var count = 0
    var n = n
    while n > 0 {
        count += 1
        n /= 10
    }
    return count
}

// Return the sum of all digits in the given integer, excluding any digits that are divisible by 3 and are also
// divisible by 2.
// Input number should be positive
// sumDivisibleDigitsNotDivisibleBy3And2(n: 123) == 6
// sumDivisibleDigitsNotDivisibleBy3And2(n: 456) == 15
// sumDivisibleDigitsNotDivisibleBy3And2(n: 789) == 24
func sumDivisibleDigitsNotDivisibleBy3And2(n: Int) -> Int {
    var sum = 0
    var n = n
    while n > 0 {
        let digit = n % 10
        if digit % 3!= 0 && digit % 2!= 0 {
            sum += digit
        }
        n /= 10
    }
    return sum
}

// Return the product of all digits in the given integer, excluding any digits that are divisible by 3 and are also
// divisible by 2.
// Input number should be positive
// productDivisibleDigitsNotDivisibleBy3And2(n: 123) == 

func factorize(n: Int) -> [Int] {
    var factors: [Int: Int] = [:]
    var num = n
    for i in 2...n {
        while num % i == 0 {
            num /= i
            if factors[i] == nil {
                factors[i] = 1
            } else {
                factors[i]! += 1
            }
        }
    }
    return Array(factors.values)
}

func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

func productDigits(n: Int) -> Int {
    var product = 1
    var num = n
    while num > 0 {
        product *= num % 10
        num /= 10
    }
    return product
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors: [Int: Int] = [:]
    var num = n
    for i in 2...n {
        while num % i == 0 {
            num /= i
            if factors[i] == nil {
                factors[i] = 1
            } else {
                factors[i]! += 1
            }
        }
    }
    return Array(factors.values)
}

// Return the sum of all digits in the given integer.
// Input number should be positive integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
// sumDigits(n: 789) == 24
func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number should be positive integer
// productDigits(n: 123) == 6
// productDigits(n: 456) == 210
// productDigits(n: 789) == 700
func productDigits(n: Int) -> Int {
    var product = 1
    var num = n
    while num > 0 {
        product *= num % 10
        num /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number should be positive integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
// sumDigits(n: 789) == 24
func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number should be positive integer
// productDigits(n: 123) == 6
// productDigits(n: 456) == 210
// productDigits(n: 789) == 700
func productDigits(n: Int) -> Int {
    var product = 1
    var num = n
    while num > 0 {
        product *= num % 10
        num /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number should be positive integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
// sumDigits(n: 789) == 24
func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number should be positive integer
// productDigits(n: 123) == 6
// productDigits(n: 456) == 210
// productDigits(n: 789) == 700
func productDigits(n: Int) -> Int {
    var product = 1
    var num = n
    while num > 0 {
        product *= num % 10
        num /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number should be positive integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
// sumDigits(n: 789) == 24
func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number should be positive integer
// productDigits(n: 123) == 6
// productDigits(n: 456) == 210
// productDigits(n: 789) == 700
func productDigits(n: Int) -> Int {
    var product = 1
    var num

func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var number = n
    for i in 2...n {
        while number % i == 0 {
            factors.append(i)
            number /= i
        }
    }
    return factors
}

func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

func productOfDigits(n: Int) -> Int {
    var product = 1
    var number = n
    while number > 0 {
        product *= number % 10
        number /= 10
    }
    return product
}

func numberOfDigits(n: Int) -> Int {
    var number = n
    var digits = 0
    while number > 0 {
        number /= 10
        digits += 1
    }
    return digits
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var number = n
    for i in 2...n {
        while number % i == 0 {
            factors.append(i)
            number /= i
        }
    }
    return factors
}

// Return the sum of all digits in the given integer.
// Input: 1234 -> Output: 10
// Input: 9876 -> Output: 36
func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input: 1234 -> Output: 120
// Input: 9876 -> Output: 720
func productOfDigits(n: Int) -> Int {
    var product = 1
    var number = n
    while number > 0 {
        product *= number % 10
        number /= 10
    }
    return product
}

// Return the number of digits in the given integer.
// Input: 1234 -> Output: 4
// Input: 9876 -> Output: 4
func numberOfDigits(n: Int) -> Int {
    var number = n
    var digits = 0
    while number > 0 {
        number /= 10
        digits += 1
    }
    return digits
}

// Return the sum of all digits in the given integer.
// Input: 1234 -> Output: 10
// Input: 9876 -> Output: 36
func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input: 1234 -> Output: 120
// Input: 9876 -> Output: 720
func productOfDigits(n: Int) -> Int {
    var product = 1
    var number = n
    while number > 0 {
        product *= number % 10
        number /= 10
    }
    return product
}

// Return the number of digits in the given integer.
// Input: 1234 -> Output: 4
// Input: 9876 -> Output: 4
func numberOfDigits(n: Int) -> Int {
    var number = n
    var digits = 0
    while number > 0 {
        number /= 10
        digits += 1
    }
    return digits
}

// Return the sum of all digits in the given integer.
// Input: 1234 -> Output: 10
// Input: 9876 -> Output: 36
func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input: 1234 -> Output: 120
// Input: 9876 -> Output: 720
func productOfDigits(n: Int) -> Int {
    var product = 1
    var number = n
    while number > 0 {
        product *= number % 10
        number /= 10
    }
    return product
}

// Return the number of digits in the given integer.
// Input: 1234 -> Output: 4
// Input: 9876 -> Output: 4
func numberOfDigits(n: Int) -> Int {
    var number = n
    var digits = 0
    while number > 0 {
        number /= 10
        digits += 1
    }
    return digits
}

// Return the sum of all digits in the given integer.
// Input: 1234 -> Output: 10
// Input: 9876 -> Output: 36
func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input: 1234 -> Output: 

func factorize(n: Int) -> [Int] {
    var factors: [Int: Int] = [:]
    var number = n
    var factor = 2

    while factor * factor <= number {
        if number % factor == 0 {
            factors[factor, default: 0] += 1
            number /= factor
        } else {
            factor += 1
        }
    }

    factors[number, default: 0] += 1

    return Array(factors.map { $0.key ** $0.value })
}

func findPrimes(in range: ClosedRange<Int>) -> [Int] {
    var primes: [Int] = []

    for number in range {
        if isPrime(number) {
            primes.append(number)
        }
    }

    return primes
}

func isPrime(_ number: Int) -> Bool {
    if number <= 1 {
        return false
    }

    for factor in 2...number {
        if number % factor == 0 {
            return false
        }
    }

    return true
}

func sum(in range: ClosedRange<Int>) -> Int {
    return range.reduce(0, +)
}

func sumOfPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).reduce(0, +)
}

func sumOfEvenPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).filter { $0 % 2 == 0 }.reduce(0, +)
}

func sumOfOddPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).filter { $0 % 2!= 0 }.reduce(0, +)
}

func productOfPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).reduce(1, *)
}

func productOfEvenPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).filter { $0 % 2 == 0 }.reduce(1, *)
}

func productOfOddPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).filter { $0 % 2!= 0 }.reduce(1, *)
}

func sumOfNumbersDivisibleBy3(in range: ClosedRange<Int>) -> Int {
    return range.filter { $0 % 3 == 0 }.reduce(0, +)
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors: [Int: Int] = [:]
    var number = n
    var factor = 2

    while factor * factor <= number {
        if number % factor == 0 {
            factors[factor, default: 0] += 1
            number /= factor
        } else {
            factor += 1
        }
    }

    factors[number, default: 0] += 1

    return Array(factors.map { $0.key ** $0.value })
}

// Return array of all prime numbers in the given range.
// The range is inclusive.
// Input range: 1...10
// Output: [2, 3, 5, 7]
func findPrimes(in range: ClosedRange<Int>) -> [Int] {
    var primes: [Int] = []

    for number in range {
        if isPrime(number) {
            primes.append(number)
        }
    }

    return primes
}

// Return true if the given number is prime, false otherwise.
// A number is prime if it is greater than 1 and its only factors are 1 and itself.
// Input: 2
// Output: true
// Input: 4
// Output: false
func isPrime(_ number: Int) -> Bool {
    if number <= 1 {
        return false
    }

    for factor in 2...number {
        if number % factor == 0 {
            return false
        }
    }

    return true
}

// Return the sum of all numbers in the given range.
// The range is inclusive.
// Input range: 1...10
// Output: 55
func sum(in range: ClosedRange<Int>) -> Int {
    return range.reduce(0, +)
}

// Return the sum of all prime numbers in the given range.
// The range is inclusive.
// Input range: 1...10
// Output: 17
func sumOfPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).reduce(0, +)
}

// Return the sum of all even prime numbers in the given range.
// The range is inclusive.
// Input range: 1...10
// Output: 10
func sumOfEvenPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).filter { $0 % 2 == 0 }.reduce(0, +)
}

// Return the sum of all odd prime numbers in the given range.
// The range is inclusive.
// Input range: 1...10
// Output: 17
func sumOfOddPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).filter { $0 % 2!= 0 }.reduce(0, +)
}

// Return the product of all prime numbers in the given range.
// The range is inclusive.
// Input range: 1...10
// Output: 3134
func productOfPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).reduce(1, *)
}

// Return the product of all even prime numbers in the given range.
// The range is inclusive.
// Input range: 1...10
// Output: 32
func productOfEvenPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).filter { $0 % 2 == 0 }.reduce(1, *)
}

// Return the product of all odd prime numbers in the given range.
// The range is inclusive.
// Input range: 1...10
// Output: 929
func productOfOddPrimes(in range: ClosedRange<Int>) -> Int {
    return findPrimes(in: range).filter { $0 % 2!= 0 }.reduce(1, *)
}

// Return the sum of all numbers divisible by 3 in the given range.
// The range is inclusive.
// Input range: 1...100
// Output: 66
func sumOfNumbersDivisibleBy3(in range: ClosedRange<Int>) -> Int {
    return range.filter { $0 % 3 == 0 }.reduce(0, +)
}

// Return the sum of all squares of even prime numbers in the given range.
//

func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var number = n
    var divisor = 2
    while divisor <= number {
        if number % divisor == 0 {
            factors.append(divisor)
            number /= divisor
        } else {
            divisor += 1
        }
    }
    return factors
}

func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

func countDigits(n: Int) -> Int {
    var number = n
    var digits = 0
    while number > 0 {
        digits += 1
        number /= 10
    }
    return digits
}

func productOfDigits(n: Int) -> Int {
    var product = 1
    var number = n
    while number > 0 {
        product *= number % 10
        number /= 10
    }
    return product
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var number = n
    var divisor = 2
    while divisor <= number {
        if number % divisor == 0 {
            factors.append(divisor)
            number /= divisor
        } else {
            divisor += 1
        }
    }
    return factors
}

// Return the sum of all digits in the given integer.
// Input number: 12345
// Output: 15
func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

// Return the number of digits in the given integer.
// Input number: 12345
// Output: 5
func countDigits(n: Int) -> Int {
    var number = n
    var digits = 0
    while number > 0 {
        digits += 1
        number /= 10
    }
    return digits
}

// Return the product of all digits in the given integer.
// Input number: 12345
// Output: 120
func productOfDigits(n: Int) -> Int {
    var product = 1
    var number = n
    while number > 0 {
        product *= number % 10
        number /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number: 12345
// Output: 15
func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

// Return the number of digits in the given integer.
// Input number: 12345
// Output: 5
func countDigits(n: Int) -> Int {
    var number = n
    var digits = 0
    while number > 0 {
        digits += 1
        number /= 10
    }
    return digits
}

// Return the product of all digits in the given integer.
// Input number: 12345
// Output: 120
func productOfDigits(n: Int) -> Int {
    var product = 1
    var number = n
    while number > 0 {
        product *= number % 10
        number /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number: 12345
// Output: 15
func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

// Return the number of digits in the given integer.
// Input number: 12345
// Output: 5
func countDigits(n: Int) -> Int {
    var number = n
    var digits = 0
    while number > 0 {
        digits += 1
        number /= 10
    }
    return digits
}

// Return the product of all digits in the given integer.
// Input number: 12345
// Output: 120
func productOfDigits(n: Int) -> Int {
    var product = 1
    var number = n
    while number > 0 {
        product *= number % 10
        number /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number: 12345
// Output: 15
func sumOfDigits(n: Int) -> Int {
    var sum = 0
    var number = n
    while number > 0 {
        sum += number % 10
        number /= 10
    }
    return sum
}

// Return the number of digits in the given integer.
// Input number: 12345
// Output: 5
func countDigits(n: Int) -> Int {
    var number = n
    var digits = 0
    while number > 0 {
        digits += 1
        number /= 10
    }
    return digits
}

// Return the product of all digits in the given integer.
// Input number: 12345
// Output: 120
func productOfDigits(n: Int) -> Int {
    var product = 

func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var num = n
    var i = 2
    while i <= num {
        if num % i == 0 {
            factors.append(i)
            num /= i
            i = 1
        } else {
            i += 1
        }
    }
    return factors
}

func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

func productDigits(n: Int) -> Int {
    var product = 1
    var num = n
    while num > 0 {
        product *= num % 10
        num /= 10
    }
    return product
}

```swift
// Return array of prime factors of given integer in the order from smallest to largest.
// Each of the factors should be arrayed number of times corresponding to how many times it appeares in factorization.
// Input number should be equal to the product of all factors
// factorize(n: 8) == [2, 2, 2]
// factorize(n: 25) == [5, 5]
// factorize(n: 70) == [2, 5, 7]
func factorize(n: Int) -> [Int] {
    var factors: [Int] = []
    var num = n
    var i = 2
    while i <= num {
        if num % i == 0 {
            factors.append(i)
            num /= i
            i = 1
        } else {
            i += 1
        }
    }
    return factors
}

// Return the sum of all digits in the given integer.
// Input number is positive integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number is positive integer
// productDigits(n: 123) == 6
// productDigits(n: 456) == 100
func productDigits(n: Int) -> Int {
    var product = 1
    var num = n
    while num > 0 {
        product *= num % 10
        num /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number is positive integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number is positive integer
// productDigits(n: 123) == 6
// productDigits(n: 456) == 100
func productDigits(n: Int) -> Int {
    var product = 1
    var num = n
    while num > 0 {
        product *= num % 10
        num /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number is positive integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number is positive integer
// productDigits(n: 123) == 6
// productDigits(n: 456) == 100
func productDigits(n: Int) -> Int {
    var product = 1
    var num = n
    while num > 0 {
        product *= num % 10
        num /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number is positive integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number is positive integer
// productDigits(n: 123) == 6
// productDigits(n: 456) == 100
func productDigits(n: Int) -> Int {
    var product = 1
    var num = n
    while num > 0 {
        product *= num % 10
        num /= 10
    }
    return product
}

// Return the sum of all digits in the given integer.
// Input number is positive integer
// sumDigits(n: 123) == 6
// sumDigits(n: 456) == 15
func sumDigits(n: Int) -> Int {
    var sum = 0
    var num = n
    while num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

// Return the product of all digits in the given integer.
// Input number is positive integer
// product

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if seen.contains(number) {
            continue
        }
        seen.insert(number)
        result.append(number)
    }
    return result
}

func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if seen.contains(number) {
            continue
        }
        seen.insert(number)
        result.append(number)
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Remove duplicates in place.
// removeDuplicatesInPlace(numbers: &numbers)
func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

// From an array of integers, remove all elements that occur more than twice.
// Remove duplicates in place.
// removeDuplicatesInPlace(numbers: &numbers)
func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

// From an array of integers, remove all elements that occur more than twice.
// Remove duplicates in place.
// removeDuplicatesInPlace(numbers: &numbers)
func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

// From an array of integers, remove all elements that occur more than twice.
// Remove duplicates in place.
// removeDuplicatesInPlace(numbers: &numbers)
func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

// From an array of integers, remove all elements that occur more than twice.
// Remove duplicates in place.
// removeDuplicatesInPlace(numbers: &numbers)
func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

// From an array of integers, remove all elements that occur more than twice.
// Remove duplicates in place.
// removeDuplicatesInPlace(numbers: &numbers)
func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

// From an array of integers, remove all elements that occur more than twice.
// Remove duplicates in place.
// removeDuplicatesInPlace(numbers: &numbers)
func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

func removeDuplicatesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

func removeDuplicatesInPlace2(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

func removeDuplicatesInPlace3(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

func removeDuplicatesInPlace4(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

func removeDuplicatesInPlace5(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

func removeDuplicatesInPlace6(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than once.
// Remove elements in-place, modifying the input array.
// removeDuplicatesInPlace(numbers: &numbers) == [1, 3, 4]
func removeDuplicatesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur more than once.
// Remove elements in-place, modifying the input array.
// removeDuplicatesInPlace(numbers: &numbers) == [1, 3, 4]
func removeDuplicatesInPlace2(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur more than once.
// Remove elements in-place, modifying the input array.
// removeDuplicatesInPlace(numbers: &numbers) == [1, 3, 4]
func removeDuplicatesInPlace3(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur more than once.
// Remove elements in-place, modifying the input array.
// removeDuplicatesInPlace(numbers: &numbers) == [1, 3, 4]
func removeDuplicatesInPlace4(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur more than once.
// Remove elements in-place, modifying the input array.
// removeDuplicatesInPlace(numbers: &numbers) == [1, 3, 4]
func removeDuplicatesInPlace5(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur more than once.
// Remove elements in-place, modifying the input array.
// removeDuplicatesInPlace(numbers: &numbers) == [1, 3, 4]
func removeDuplicatesInPlace6(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur more than once.
// Remove elements in-place, modifying the input array.
// removeDuplicatesInPlace(numbers: &numbers) == [1, 3, 4]
func removeDuplicatesInPlace7(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i])

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

func removeDuplicatesAndSort(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result.sorted()
}

func removeDuplicatesAndSortDescending(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result.sorted(by: >)
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than once.
// Sort the elements in the result in ascending order.
// removeDuplicatesAndSort(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicatesAndSort(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result.sorted()
}

// From an array of integers, remove all elements that occur more than once.
// Sort the elements in the result in descending order.
// removeDuplicatesAndSortDescending(numbers: [1, 2, 3, 2, 4]) == [4, 3, 2, 1]
func removeDuplicatesAndSortDescending(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result.sorted(by: >)
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicates and sort in ascending order.
// removeDuplicatesAndSort(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicatesAndSort(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result.sorted()
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicates and sort in descending order.
// removeDuplicatesAndSortDescending(numbers: [1, 2, 3, 2, 4]) == [4, 3, 2, 1]
func removeDuplicatesAndSortDescending(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result.sorted(by: >)
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicates and sort in descending order.
// removeDuplicatesAndSortDescending(numbers: [1, 2, 3, 2, 4]) == [4, 3, 2, 1]
func removeDuplicatesAndSortDescending(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result.sorted(by: >)
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicates and sort in descending order.
// removeDuplicatesAndSortDescending(numbers: [1, 2, 3, 2, 4]) == [4, 3, 2, 1]
func removeDuplicatesAndSortDescending(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result.sorted(by: >)
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicates and sort in descending order.
// removeDuplicatesAndSortDescending(numbers: [1, 2, 3, 2, 4]) == [4, 3, 2, 1]
func removeDuplicatesAndSortDescending(numbers: [Int])

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if seen.contains(number) {
            continue
        }
        seen.insert(number)
        result.append(number)
    }
    return result
}

func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

func removeDuplicatesInPlace2(numbers: inout [Int]) {
    var i = 0
    while i < numbers.count {
        var j = i + 1
        while j < numbers.count {
            if numbers[i] == numbers[j] {
                numbers.remove(at: j)
            } else {
                j += 1
            }
        }
        i += 1
    }
}

func removeDuplicatesInPlace3(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

func removeDuplicatesInPlace4(numbers: inout [Int]) {
    var i = 0
    while i < numbers.count {
        var j = i + 1
        while j < numbers.count {
            if numbers[i] == numbers[j] {
                numbers.remove(at: j)
            } else {
                j += 1
            }
        }
        i += 1
    }
}

func removeDuplicatesInPlace5(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if seen.contains(number) {
            continue
        }
        seen.insert(number)
        result.append(number)
    }
    return result
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicate elements in place.
// removeDuplicatesInPlace([1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicatesInPlace(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicate elements in place.
// removeDuplicatesInPlace([1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicatesInPlace2(numbers: inout [Int]) {
    var i = 0
    while i < numbers.count {
        var j = i + 1
        while j < numbers.count {
            if numbers[i] == numbers[j] {
                numbers.remove(at: j)
            } else {
                j += 1
            }
        }
        i += 1
    }
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicate elements in place.
// removeDuplicatesInPlace([1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicatesInPlace3(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicate elements in place.
// removeDuplicatesInPlace([1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicatesInPlace4(numbers: inout [Int]) {
    var i = 0
    while i < numbers.count {
        var j = i + 1
        while j < numbers.count {
            if numbers[i] == numbers[j] {
                numbers.remove(at: j)
            } else {
                j += 1
            }
        }
        i += 1
    }
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicate elements in place.
// removeDuplicatesInPlace([1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicatesInPlace5(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
}

// From an array of integers, remove all elements that occur more than once.
// Remove duplicate elements in place.
// removeDuplicatesInPlace([1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicatesInPlace6(numbers: inout [Int]) {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

func removeDuplicatesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

func removeSingles(numbers: [Int]) -> [Int] {
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
        }
    }
    return Array(seen)
}

func removeSinglesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

func multiplyByTwo(numbers: [Int]) -> [Int] {
    var result = [Int]()
    for number in numbers {
        result.append(number * 2)
    }
    return result
}

func multiplyByTwoInPlace(numbers: inout [Int]) -> [Int] {
    for i in 0..<numbers.count {
        numbers[i] *= 2
    }
    return numbers
}

func divideByTwo(numbers: [Int]) -> [Int] {
    var result = [Int]()
    for number in numbers {
        result.append(number / 2)
    }
    return result
}

func divideByTwoInPlace(numbers: inout [Int]) -> [Int] {
    for i in 0..<numbers.count {
        numbers[i] /= 2
    }
    return numbers
}

func square(numbers: [Int]) -> [Int] {
    var result = [Int]()
    for number in numbers {
        result.append(number * number)
    }
    return result
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than once.
// Remove elements in-place, modifying the original array.
// removeDuplicatesInPlace(numbers: &numbers) == [1, 3, 4]
func removeDuplicatesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur only once.
// Return a new array with the elements that occur only once.
// removeSingles(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeSingles(numbers: [Int]) -> [Int] {
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
        }
    }
    return Array(seen)
}

// From an array of integers, remove all elements that occur only once.
// Remove elements in-place, modifying the original array.
// removeSinglesInPlace(numbers: &numbers) == [1, 2, 3, 4]
func removeSinglesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// Given an array of integers, return a new array with all values
// multiplied by 2.
// multiplyByTwo(numbers: [1, 2, 3, 4]) == [2, 4, 6, 8]
func multiplyByTwo(numbers: [Int]) -> [Int] {
    var result = [Int]()
    for number in numbers {
        result.append(number * 2)
    }
    return result
}

// Given an array of integers, multiply each value in the array by 2.
// multiplyByTwoInPlace(numbers: &numbers) == [2, 4, 6, 8]
func multiplyByTwoInPlace(numbers: inout [Int]) -> [Int] {
    for i in 0..<numbers.count {
        numbers[i] *= 2
    }
    return numbers
}

// Given an array of integers, return a new array with all values
// divided by 2.
// divideByTwo(numbers: [1, 2, 3, 4]) == [0, 1, 1, 0]
func divideByTwo(numbers: [Int]) -> [Int] {
    var result = [Int]()
    for number in numbers {
        result.append(number / 2)
    }
    return result
}

// Given an array of integers, divide each value in the array by 2.
// divideByTwoInPlace(numbers: &numbers) == [0, 1, 1, 0]
func divideByTwoInPlace(numbers: inout [Int]) -> [Int] {
    for i in 0..<numbers.count {
        numbers[i] /= 2
    }
    return numbers
}

// Given an array of integers, return a new array with all values
// squared.
// square(numbers: [1, 2, 3, 4]) == [1, 4, 9, 16]
func square(numbers: [Int]) -> [Int] {
    var result = [Int]()
    for number in numbers {
        result.append(number * number)
    }
    return result
}

// Given an array of integers, square each value in the array.
// squareInPlace(numbers: &numbers) == [1, 4, 9, 16]
func squareInPlace(numbers: inout [Int]) -> [Int] {
    for i in 0..<numbers.count

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

func removeDuplicatesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

func removeSingles(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        } else if result.last == number {
            result.removeLast()
        }
    }
    return result
}

func removeSinglesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

func removeTriples(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var last = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            last = number
        } else if number == last + 1 {
            result.append(last)
            last = number
        }
    }
    result.append(last)
    return result
}

func removeTriplesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than once.
// Remove elements in-place, modifying the original array.
// removeDuplicatesInPlace(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicatesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur only once.
// Keep order of elements left the same as in the input.
// removeSingles(numbers: [1, 2, 3, 2, 4]) == [2, 2, 4]
func removeSingles(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        } else if result.last == number {
            result.removeLast()
        }
    }
    return result
}

// From an array of integers, remove all elements that occur only once.
// Remove elements in-place, modifying the original array.
// removeSinglesInPlace(numbers: [1, 2, 3, 2, 4]) == [2, 4]
func removeSinglesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur
// more than twice, but only if they are consecutive.
// Keep order of elements left the same as in the input.
// removeTriples(numbers: [1, 2, 3, 2, 4, 2, 5]) == [1, 2, 3, 4, 5]
func removeTriples(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var last = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            last = number
        } else if number == last + 1 {
            result.append(last)
            last = number
        }
    }
    result.append(last)
    return result
}

// From an array of integers, remove all elements that occur
// more than twice, but only if they are consecutive.
// Remove elements in-place, modifying the original array.
// removeTriplesInPlace(numbers: [1, 2, 3, 2, 4, 2, 5]) == [1, 2, 3, 4, 5]
func removeTriplesInPlace(numbers: inout [Int]) -> [Int] {
    var seen = Set<Int>()
    var i = 0
    while i < numbers.count {
        if seen.contains(numbers[i]) {
            numbers.remove(at: i)
        } else {
            seen.insert(numbers[i])
            i += 1
        }
    }
    return numbers
}

// From an array of integers, remove all elements that occur
// more than twice, but only if they are consecutive.
// Remove elements in-place, modifying the original array.
// removeTriplesInPlace(numbers: [1, 2, 3, 2, 4, 2, 5]) == [1, 2, 3, 4, 5]
func removeTriplesInPlace2(numbers: inout [Int]) -> [Int] {
    var i = 0
    while i < numbers.count {
        if i + 2 < numbers.count && numbers[i] == numbers[i + 2] {
           

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

func removeDuplicates2(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 2 {
            count += 1
            result.append(number)
        }
    }
    return result
}

func removeDuplicates3(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
            result.append(number)
        }
    }
    return result
}

func removeDuplicates4(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

func removeDuplicates5(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        } else if count == 2 {
            count += 1
            result.removeLast()
        }
    }
    return result
}

func removeDuplicates6(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        } else if count == 2 {
            count += 1
            result.removeLast()
        }
    }
    return result
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates2(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 2 {
            count += 1
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates3(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates4(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates5(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        } else if count == 2 {
            count += 1
            result.removeLast()
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates6(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        } else if count == 2 {
            count += 1
            result.removeLast()
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates7(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }

    return result
}

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 2 {
            count += 1
            result.append(number)
        }
    }

    return result
}

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 3 {
            count += 1
            result.append(number)
        }
    }

    return result
}

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 4 {
            count += 1
            result.append(number)
        }
    }

    return result
}

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 5 {
            count += 1
            result.append(number)
        }
    }

    return result
}

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 6 {
            count += 1
            result.append(number)
        }
    }

    return result
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }

    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 2 {
            count += 1
            result.append(number)
        }
    }

    return result
}

// From an array of integers, remove all elements that occur more than three times.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 3 {
            count += 1
            result.append(number)
        }
    }

    return result
}

// From an array of integers, remove all elements that occur more than four times.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 4 {
            count += 1
            result.append(number)
        }
    }

    return result
}

// From an array of integers, remove all elements that occur more than five times.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 5 {
            count += 1
            result.append(number)
        }
    }

    return result
}

// From an array of integers, remove all elements that occur more than six times.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 6 {
            count += 1
            result.append(number)
        }
    }

    return result
}

// From an array of integers, remove all elements that occur more than seven times.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0

    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

func removeDuplicates2(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 2 {
            count += 1
            result.append(number)
        }
    }
    return result
}

func removeDuplicates3(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
            result.append(number)
        }
    }
    return result
}

func removeDuplicates4(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

func removeDuplicates5(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        } else {
            count -= 1
        }
    }
    return result
}

func removeDuplicates6(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        } else {
            count -= 1
        }
    }
    return result
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicates2(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 2 {
            count += 1
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicates3(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicates4(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicates5(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        } else {
            count -= 1
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicates6(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        } else {
            count -= 1
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 2, 3, 4]
func removeDuplicates7(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains

func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

func removeDuplicates2(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 2 {
            count += 1
            result.append(number)
        }
    }
    return result
}

func removeDuplicates3(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
            result.append(number)
        }
    }
    return result
}

func removeDuplicates4(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

func removeDuplicates5(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

func removeDuplicates6(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

```swift
// From an array of integers, remove all elements that occur more than once.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates2(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count < 2 {
            count += 1
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates3(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
            result.append(number)
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates4(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates5(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates6(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 1
        }
    }
    return result
}

// From an array of integers, remove all elements that occur more than twice.
// Keep order of elements left the same as in the input.
// removeDuplicates(numbers: [1, 2, 3, 2, 4]) == [1, 3, 4]
func removeDuplicates7(numbers: [Int]) -> [Int] {
    var result = [Int]()
    var seen = Set<Int>()
    var count = 0
    for number in numbers {
        if!seen.contains(number) {
            seen.insert(number)
            count = 1
            result.append(number)
        } else if count == 1 {
            count += 

func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char.lowercased())
        } else {
            flippedString += String(char.uppercased())
        }
    }
    return flippedString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char.lowercased())
        } else {
            flippedString += String(char.uppercased())
        }
    }
    return flippedString
}

// Test the function
let inputString = "Hello World!"
let outputString = flipCase(string: inputString)
print(outputString)
```

func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char.lowercased())
        } else {
            flippedString += String(char.uppercased())
        }
    }
    return flippedString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char.lowercased())
        } else {
            flippedString += String(char.uppercased())
        }
    }
    return flippedString
}

// Test the function
let inputString = "Hello World!"
let outputString = flipCase(string: inputString)
print(outputString)
```

func flipCase(string: String) -> String {
    var newString = ""
    for char in string {
        if char.isUppercase {
            newString += String(char).lowercased()
        } else {
            newString += String(char).uppercased()
        }
    }
    return newString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var newString = ""
    for char in string {
        if char.isUppercase {
            newString += String(char).lowercased()
        } else {
            newString += String(char).uppercased()
        }
    }
    return newString
}

// Test Cases
assert(flipCase(string: "Hello") == "hELLO")
assert(flipCase(string: "World") == "wORLD")
assert(flipCase(string: "1234") == "1234")
assert(flipCase(string: "!@#$%") == "!@#$%")
assert(flipCase(string: "Hello World") == "hELLO wORLD")
assert(flipCase(string: "1234!@#$%") == "1234!@#$%")
assert(flipCase(string: "!@#$% World") == "!@#$% wORLD")
```

func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char).lowercased()
        } else {
            flippedString += String(char).uppercased()
        }
    }
    return flippedString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char).lowercased()
        } else {
            flippedString += String(char).uppercased()
        }
    }
    return flippedString
}

// Test the function
let inputString = "Hello World!"
let outputString = flipCase(string: inputString)
print(outputString)
```

func flipCase(string: String) -> String {
    var newString = ""
    for char in string {
        if char.isUppercase {
            newString += String(char).lowercased()
        } else {
            newString += String(char).uppercased()
        }
    }
    return newString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var newString = ""
    for char in string {
        if char.isUppercase {
            newString += String(char).lowercased()
        } else {
            newString += String(char).uppercased()
        }
    }
    return newString
}

// Test the function
let inputString = "Hello World!"
let outputString = flipCase(string: inputString)
print(outputString)
```

func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char.lowercased())
        } else {
            flippedString += String(char.uppercased())
        }
    }
    return flippedString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char.lowercased())
        } else {
            flippedString += String(char.uppercased())
        }
    }
    return flippedString
}

// Test the function
let inputString = "Hello World!"
let outputString = flipCase(string: inputString)
print(outputString)
```

func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char.lowercased())
        } else {
            flippedString += String(char.uppercased())
        }
    }
    return flippedString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char.lowercased())
        } else {
            flippedString += String(char.uppercased())
        }
    }
    return flippedString
}

// Test Cases
flipCase(string: "Hello") // "hELLO"
flipCase(string: "World") // "wORLD"
flipCase(string: "Python Programming") // "pYTHON pROGRAMMING"
flipCase(string: "1234") // "1234"
flipCase(string: "!@#$%") // "!@#$%"
```

func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char).lowercased()
        } else {
            flippedString += String(char).uppercased()
        }
    }
    return flippedString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var flippedString = ""
    for char in string {
        if char.isUppercase {
            flippedString += String(char).lowercased()
        } else {
            flippedString += String(char).uppercased()
        }
    }
    return flippedString
}

// Test Cases
assert(flipCase(string: "Hello") == "hELLO")
assert(flipCase(string: "World") == "wORLD")
assert(flipCase(string: "Hello World") == "hELLO wORLD")
assert(flipCase(string: "1234") == "1234")
assert(flipCase(string: "!@#$%") == "!@#$%")
```

func flipCase(string: String) -> String {
    var newString = ""
    for char in string {
        if char.isUppercase {
            newString += String(char).lowercased()
        } else {
            newString += String(char).uppercased()
        }
    }
    return newString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var newString = ""
    for char in string {
        if char.isUppercase {
            newString += String(char).lowercased()
        } else {
            newString += String(char).uppercased()
        }
    }
    return newString
}

// Test the function
let inputString = "Hello World"
let outputString = flipCase(string: inputString)
print(outputString)
```

func flipCase(string: String) -> String {
    var newString = ""
    for char in string {
        if char.isUppercase {
            newString += String(char).lowercased()
        } else {
            newString += String(char).uppercased()
        }
    }
    return newString
}

```swift
// For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
// flipCase(string: "Hello") == "hELLO"
func flipCase(string: String) -> String {
    var newString = ""
    for char in string {
        if char.isUppercase {
            newString += String(char).lowercased()
        } else {
            newString += String(char).uppercased()
        }
    }
    return newString
}

// Test the function
let inputString = "Hello World!"
let outputString = flipCase(string: inputString)
print(outputString)
```

func concatenate(strings: [String]) -> String {
    return strings.joined()
}

func allUniqueCharacters(string: String) -> Bool {
    return Set(string).count == string.count
}

func reverse(string: String) -> String {
    return String(string.reversed())
}

func removeDuplicates(string: String) -> String {
    var characters = Set<Character>()
    var result = ""
    for character in string {
        if!characters.contains(character) {
            characters.insert(character)
            result.append(character)
        }
    }
    return result
}

func areAnagrams(string1: String, string2: String) -> Bool {
    if string1.count!= string2.count {
        return false
    }
    var characters = [Character: Int]()
    for character in string1 {
        characters[character, default: 0] += 1
    }
    for character in string2 {
        if let count = characters[character] {
            characters[character] = count - 1
            if characters[character] == 0 {
                characters[character] = nil
            }
        } else {
            return false
        }
    }
    return true
}

func isPalindrome(string: String) -> Bool {
    if string.count == 0 || string.count == 1 {
        return true
    }
    if string.count == 2 {
        return string[string.startIndex] == string[string.index(after: string.startIndex)]
    }
    let middleIndex = string.index(string.startIndex, offsetBy: Int(string.count / 2))
    let firstHalf = String(string[string.startIndex...middleIndex])
    let secondHalf = String(string[string.index(after: middleIndex)...string.endIndex])
    return firstHalf == String(secondHalf.reversed())
}

func removeSpecialCharacters(string: String) -> String {
    var result = ""
    for character in string {
        if character.isLetter || character.isNumber {
            result.append(character)
        }
    }
    return result
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    return strings.joined()
}

// Determine if a string contains only unique characters
// allUniqueCharacters(string: "") == true
// allUniqueCharacters(string: "abc") == true
// allUniqueCharacters(string: "abcabc") == false
func allUniqueCharacters(string: String) -> Bool {
    return Set(string).count == string.count
}

// Reverse a string
// reverse(string: "") == ""
// reverse(string: "a") == "a"
// reverse(string: "ab") == "ba"
// reverse(string: "abc") == "cba"
func reverse(string: String) -> String {
    return String(string.reversed())
}

// Remove duplicate characters from a string
// removeDuplicates(string: "") == ""
// removeDuplicates(string: "a") == "a"
// removeDuplicates(string: "ab") == "ab"
// removeDuplicates(string: "abc") == "abc"
// removeDuplicates(string: "abbc") == "abc"
func removeDuplicates(string: String) -> String {
    var characters = Set<Character>()
    var result = ""
    for character in string {
        if!characters.contains(character) {
            characters.insert(character)
            result.append(character)
        }
    }
    return result
}

// Check if two strings are anagrams
// areAnagrams(string1: "", string2: "") == true
// areAnagrams(string1: "a", string2: "a") == true
// areAnagrams(string1: "ab", string2: "ba") == true
// areAnagrams(string1: "abc", string2: "cba") == true
// areAnagrams(string1: "abbc", string2: "cba") == false
func areAnagrams(string1: String, string2: String) -> Bool {
    if string1.count!= string2.count {
        return false
    }
    var characters = [Character: Int]()
    for character in string1 {
        characters[character, default: 0] += 1
    }
    for character in string2 {
        if let count = characters[character] {
            characters[character] = count - 1
            if characters[character] == 0 {
                characters[character] = nil
            }
        } else {
            return false
        }
    }
    return true
}

// Determine if a string is a palindrome
// isPalindrome(string: "") == true
// isPalindrome(string: "a") == true
// isPalindrome(string: "ab") == false
// isPalindrome(string: "abc") == false
// isPalindrome(string: "abba") == true
// isPalindrome(string: "abcba") == true
func isPalindrome(string: String) -> Bool {
    if string.count == 0 || string.count == 1 {
        return true
    }
    if string.count == 2 {
        return string[string.startIndex] == string[string.index(after: string.startIndex)]
    }
    let middleIndex = string.index(string.startIndex, offsetBy: Int(string.count / 2))
    let firstHalf = String(string[string.startIndex...middleIndex])
    let secondHalf = String(string[string.index(after: middleIndex)...string.endIndex])
    return firstHalf == String(secondHalf.reversed())
}

// Remove all whitespace, punctuation, and special characters from a string
// removeSpecialCharacters(string: "") == ""
// removeSpecialCharacters(string: "a") == "a"
// removeSpecialCharacters(string: "abc") == "abc"
// removeSpecialCharacters(string: "ab,c") == "abc"
// removeSpecialCharacters(string: "a!bc") == "abc"
// removeSpecialCharacters(string: "a!bc 123") == "abc123"
func removeSpecialCharacters(string: String) -> String {
    var result = ""
    for character in string {
        if character.isLetter || character.isNumber {
            result.append(character)
        }
    }
    return result
}

// Check if a string is a palindrome with special characters and whitespace removed
// isPalindromeWithoutSpecialCharacters(string: "") == true
// isPalindromeWithoutSpecialCharacters(string: "a") == true
// isPalindromeWithoutSpecialCharacters(string: "ab

func concatenate(strings: [String]) -> String {
    var result = ""
    for string in strings {
        result += string
    }
    return result
}

func reverse(string: String) -> String {
    var result = ""
    for char in string {
        result = "\(char)" + result
    }
    return result
}

func countOccurrences(in string: String, character: Character) -> Int {
    var count = 0
    for char in string {
        if char == character {
            count += 1
        }
    }
    return count
}

func removeDuplicates(from string: String) -> String {
    var result = ""
    for char in string {
        if!result.contains(char) {
            result += "\(char)"
        }
    }
    return result
}

func isPalindrome(string: String) -> Bool {
    if string.count == 0 {
        return true
    }
    if string.count == 1 {
        return true
    }
    if string.count == 2 {
        return string[string.startIndex] == string[string.index(after: string.startIndex)]
    }
    let first = string[string.startIndex]
    let last = string[string.index(before: string.endIndex)]
    if first == last {
        return isPalindrome(string: String(string.suffix(from: string.index(after: string.startIndex) )))
    } else {
        return false
    }
}

func removeWhitespace(string: String) -> String {
    var result = ""
    for char in string {
        if char!= " " {
            result += "\(char)"
        }
    }
    return result
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    var result = ""
    for string in strings {
        result += string
    }
    return result
}

// Reverse the characters in a string
// reverse(string: "") == ""
// reverse(string: "a") == "a"
// reverse(string: "ab") == "ba"
// reverse(string: "abc") == "cba"
func reverse(string: String) -> String {
    var result = ""
    for char in string {
        result = "\(char)" + result
    }
    return result
}

// Count the number of occurrences of a character in a string
// countOccurrences(in: "", character: "") == 0
// countOccurrences(in: "a", character: "a") == 1
// countOccurrences(in: "ab", character: "a") == 1
// countOccurrences(in: "ab", character: "b") == 1
// countOccurrences(in: "abc", character: "a") == 1
// countOccurrences(in: "abc", character: "b") == 1
// countOccurrences(in: "abc", character: "c") == 1
// countOccurrences(in: "abc", character: "d") == 0
func countOccurrences(in string: String, character: Character) -> Int {
    var count = 0
    for char in string {
        if char == character {
            count += 1
        }
    }
    return count
}

// Remove duplicate characters from a string
// removeDuplicates(from: "") == ""
// removeDuplicates(from: "a") == "a"
// removeDuplicates(from: "ab") == "ab"
// removeDuplicates(from: "aba") == "ab"
// removeDuplicates(from: "abc") == "abc"
// removeDuplicates(from: "abca") == "abc"
// removeDuplicates(from: "abcba") == "abc"
func removeDuplicates(from string: String) -> String {
    var result = ""
    for char in string {
        if!result.contains(char) {
            result += "\(char)"
        }
    }
    return result
}

// Check if a string is a palindrome
// isPalindrome(string: "") == true
// isPalindrome(string: "a") == true
// isPalindrome(string: "ab") == true
// isPalindrome(string: "abc") == false
// isPalindrome(string: "abba") == true
// isPalindrome(string: "abcba") == true
// isPalindrome(string: "abcdba") == false
func isPalindrome(string: String) -> Bool {
    if string.count == 0 {
        return true
    }
    if string.count == 1 {
        return true
    }
    if string.count == 2 {
        return string[string.startIndex] == string[string.index(after: string.startIndex)]
    }
    let first = string[string.startIndex]
    let last = string[string.index(before: string.endIndex)]
    if first == last {
        return isPalindrome(string: String(string.suffix(from: string.index(after: string.startIndex) )))
    } else {
        return false
    }
}

// Remove all whitespace characters from a string
// removeWhitespace(string: "") == ""
// removeWhitespace(string: "a") == "a"
// removeWhitespace(string: "ab") == "ab"
// removeWhitespace(string: "a ") == "a"
// removeWhitespace(string: "a b") == "a b"
// removeWhitespace(string: "a  b") == "a b"
// removeWhitespace(string: "a  b  ") == "a b"
func removeWhitespace(string: String) -> String {
    var result = ""
    for char in string {
        if char!= " " {
            result += "\(char)"
        }
    }
    return result
}

// Split a string into an array of words
// splitIntoWords(string: "") == []
// splitIntoWords(string: "a") == ["a"]
// splitIntoWords(string: "ab") == ["ab"]
// splitIntoWords(string: "abc") == ["abc"]
// splitIntoWords(string: "a b c") == ["a", "b", "c"]
// splitIntoWords(string:

func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

func firstNonEmpty(strings: [String]) -> String? {
    for string in strings {
        if!string.isEmpty {
            return string
        }
    }
    return nil
}

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest!.count {
            longest = string
        }
    }
    return longest
}

func vowelStrings(from strings: [String]) -> [String] {
    var vowelStrings = [String]()
    for string in strings {
        if "aeiou".contains(string.prefix(1)) {
            vowelStrings.append(string)
        }
    }
    return vowelStrings
}

func substringStrings(from strings: [String], containing substring: String) -> [String] {
    var substringStrings = [String]()
    for string in strings {
        if string.contains(substring) {
            substringStrings.append(string)
        }
    }
    return substringStrings
}

func lengthStrings(from strings: [String], withLength length: Int) -> [String] {
    var lengthStrings = [String]()
    for string in strings {
        if string.count == length {
            lengthStrings.append(string)
        }
    }
    return lengthStrings
}

func vowelLengthStrings(from strings: [String], withLength length: Int) -> [String] {
    var vowelLengthStrings = [String]()
    for string in strings {
        if "aeiou".contains(string.prefix(1)) && string.count == length {
            vowelLengthStrings.append(string)
        }
    }
    return vowelLengthStrings
}

func vowelLengthSubstringStrings(from strings: [String], containing substring: String, withLength length: Int) -> [String] {
    var vowelLengthSubstringStrings = [String]()
    for string in strings {
        if "aeiou".contains(string.prefix(1)) && string.count == length && string.contains(substring) {
            vowelLengthSubstringStrings.append(string)
        }
    }
    return vowelLengthSubstringStrings
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

// Return the first non-empty string from an array of strings
// firstNonEmpty(strings: [] as [String]) == nil
// firstNonEmpty(strings: ["a", "b", "c"]) == "a"
func firstNonEmpty(strings: [String]) -> String? {
    for string in strings {
        if!string.isEmpty {
            return string
        }
    }
    return nil
}

// Return the longest string from an array of strings
// longest(strings: [] as [String]) == nil
// longest(strings: ["abc", "def", "ghij"]) == "ghij"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest!.count {
            longest = string
        }
    }
    return longest
}

// Return an array of strings containing only the strings that begin with a vowel
// vowelStrings(from: []) == []
// vowelStrings(from: ["apple", "banana", "orange"]) == ["apple", "orange"]
func vowelStrings(from strings: [String]) -> [String] {
    var vowelStrings = [String]()
    for string in strings {
        if "aeiou".contains(string.prefix(1)) {
            vowelStrings.append(string)
        }
    }
    return vowelStrings
}

// Return an array of strings containing only the strings that contain a specific substring
// substringStrings(from: [], containing: "") == []
// substringStrings(from: ["apple", "banana", "orange"], containing: "an") == ["banana", "orange"]
func substringStrings(from strings: [String], containing substring: String) -> [String] {
    var substringStrings = [String]()
    for string in strings {
        if string.contains(substring) {
            substringStrings.append(string)
        }
    }
    return substringStrings
}

// Return an array of strings containing only the strings that have a specific length
// lengthStrings(from: [], withLength: 0) == []
// lengthStrings(from: ["apple", "banana", "orange"], withLength: 5) == ["apple", "banana"]
func lengthStrings(from strings: [String], withLength length: Int) -> [String] {
    var lengthStrings = [String]()
    for string in strings {
        if string.count == length {
            lengthStrings.append(string)
        }
    }
    return lengthStrings
}

// Return an array of strings containing only the strings that start with a vowel and have a specific length
// vowelLengthStrings(from: [], withLength: 0) == []
// vowelLengthStrings(from: ["apple", "banana", "orange"], withLength: 5) == ["apple"]
func vowelLengthStrings(from strings: [String], withLength length: Int) -> [String] {
    var vowelLengthStrings = [String]()
    for string in strings {
        if "aeiou".contains(string.prefix(1)) && string.count == length {
            vowelLengthStrings.append(string)
        }
    }
    return vowelLengthStrings
}

// Return an array of strings containing only the strings that start with a vowel, have a specific length,
// and contain a specific substring
// vowelLengthSubstringStrings(from: [], containing: "", withLength: 0) == []
// vowelLengthSubstringStrings(from: ["apple", "banana", "orange"], containing: "an", withLength: 5) == ["apple"]
func vowelLengthSubstringStrings(from strings: [String], containing substring: String, withLength length: Int) -> [String] {
    var vowelLengthSubstringStrings = [String]()
    for string in strings {
        if "aeiou".contains(string.prefix(1)) && string.count == length && string.contains(substring) {
            vowelLengthSubstringStrings.append(string)
        }
    }
    return vowelLengthSubstringStrings
}

// Return an array of strings sorted in alphabetical order
// sortStrings(strings: []) == []
// sortStrings(strings: ["cat", "apple", "dog", "elephant", "orange"]) == ["apple", "cat", "dog", "elephant", "orange"]
func sortStrings(strings: [

func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

func longestLength(strings: [String]) -> Int {
    return strings.map { $0.count }.max()?? 0
}

func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}

func shortest(strings: [String]) -> String? {
    return strings.min { $0.count < $1.count }
}

func sort(strings: [String]) -> [String] {
    return strings.sorted()
}

func reverseSort(strings: [String]) -> [String] {
    return strings.sorted(by: >)
}

func unique(strings: [String]) -> [String] {
    return Array(Set(strings))
}

func removePrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) == false }
}

func removeSuffix(strings: [String], suffix: String) -> [String] {
    return strings.filter { $0.hasSuffix(suffix) == false }
}

func removeWhitespace(strings: [String]) -> [String] {
    return strings.map { $0.trimmingCharacters(in:.whitespaces) }
}

func removePunctuation(strings: [String]) -> [String] {
    return strings.map { $0.trimmingCharacters(in: CharacterSet.punctuationCharacters) }
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

// Return the length of the longest string in the array
// longestLength(strings: [] as [String]) == 0
// longestLength(strings: ["a", "ab", "abc"]) == 3
func longestLength(strings: [String]) -> Int {
    return strings.map { $0.count }.max()?? 0
}

// Return the longest string in the array
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "ab", "abc"]) == "abc"
func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}

// Return the shortest string in the array
// shortest(strings: [] as [String]) == nil
// shortest(strings: ["a", "ab", "abc"]) == "a"
func shortest(strings: [String]) -> String? {
    return strings.min { $0.count < $1.count }
}

// Return an array of strings sorted in alphabetical order
// sort(strings: [] as [String]) == []
// sort(strings: ["b", "a", "c"]) == ["a", "b", "c"]
func sort(strings: [String]) -> [String] {
    return strings.sorted()
}

// Return an array of strings sorted in reverse alphabetical order
// reverseSort(strings: [] as [String]) == []
// reverseSort(strings: ["b", "a", "c"]) == ["c", "b", "a"]
func reverseSort(strings: [String]) -> [String] {
    return strings.sorted(by: >)
}

// Return an array of strings with duplicates removed
// unique(strings: [] as [String]) == []
// unique(strings: ["a", "a", "b", "c", "b"]) == ["a", "b", "c"]
func unique(strings: [String]) -> [String] {
    return Array(Set(strings))
}

// Return an array of strings with the given prefix removed
// removePrefix(strings: [] as [String], prefix: "") == []
// removePrefix(strings: ["apple", "banana", "cherry"], prefix: "ba") == ["apple", "cherry"]
func removePrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) == false }
}

// Return an array of strings with the given suffix removed
// removeSuffix(strings: [] as [String], suffix: "") == []
// removeSuffix(strings: ["apple", "banana", "cherry"], suffix: "e") == ["apple", "banana"]
func removeSuffix(strings: [String], suffix: String) -> [String] {
    return strings.filter { $0.hasSuffix(suffix) == false }
}

// Return an array of strings with whitespace removed from each string
// removeWhitespace(strings: [] as [String]) == []
// removeWhitespace(strings: ["a", "b", "c"]) == ["a", "b", "c"]
// removeWhitespace(strings: ["a ", " b", " c "]) == ["a", "b", "c"]
func removeWhitespace(strings: [String]) -> [String] {
    return strings.map { $0.trimmingCharacters(in:.whitespaces) }
}

// Return an array of strings with punctuation marks removed from each string
// removePunctuation(strings: [] as [String]) == []
// removePunctuation(strings: ["a.", "b!", "c?"]) == ["a", "b", "c"]
// removePunctuation(strings: ["a,", "b.", "c!"]) == ["a", "b", "c"]
func removePunctuation(strings: [String]) -> [String] {
    return strings.map { $0.trimmingCharacters(in: CharacterSet.punctuationCharacters) }
}

// Return an array of strings with non-alphabetic characters removed from each string
// removeNonAlphabetic(strings: [] as [String]) == []
// removeNonAlphabetic(strings: ["a", "b2", "c"]) == ["a", "b2", "c"]
// removeNonAlphabetic(strings: ["a", "b", "c", " ", "2", "

func concatenate(strings: [String]) -> String {
    var result = ""
    for string in strings {
        result += string
    }
    return result
}

func concatenateFilter(strings: [String]) -> String {
    var result = ""
    for string in strings {
        if string.count > 3 {
            result += string
        }
    }
    return result
}

func maxLength(strings: [String]) -> Int {
    var max = 0
    for string in strings {
        if string.count > max {
            max = string.count
        }
    }
    return max
}

func filterByMinLength(strings: [String], minLength: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.count > minLength {
            result.append(string)
        }
    }
    return result
}

func sortStrings(strings: [String]) -> [String] {
    return strings.sorted()
}

func reverseSortStrings(strings: [String]) -> [String] {
    return strings.sorted(by: >)
}

func removeDuplicates(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        if!result.contains(string) {
            result.append(string)
        }
    }
    return result
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    var result = ""
    for string in strings {
        result += string
    }
    return result
}

// Concatenate array of strings into a single string, but only include strings that are longer than 3 characters
// concatenateFilter(strings: [] as [String]) == ""
// concatenateFilter(strings: ["a", "b", "c"]) == "abc"
// concatenateFilter(strings: ["a", "bc", "def"]) == "abcdef"
func concatenateFilter(strings: [String]) -> String {
    var result = ""
    for string in strings {
        if string.count > 3 {
            result += string
        }
    }
    return result
}

// Return the length of the longest string in an array of strings
// maxLength(strings: [] as [String]) == 0
// maxLength(strings: ["a", "b", "c"]) == 3
// maxLength(strings: ["a", "bc", "defg"]) == 6
func maxLength(strings: [String]) -> Int {
    var max = 0
    for string in strings {
        if string.count > max {
            max = string.count
        }
    }
    return max
}

// Return the length of the longest string in an array of strings, but only consider strings that are longer than minLength
// filterByMinLength(strings: [] as [String], minLength: 5) == []
// filterByMinLength(strings: ["a", "b", "c"], minLength: 5) == ["a", "b", "c"]
// filterByMinLength(strings: ["a", "bc", "defg"], minLength: 5) == ["a", "bc", "defg"]
// filterByMinLength(strings: ["a", "bc", "defg"], minLength: 4) == ["a", "bc", "defg"]
func filterByMinLength(strings: [String], minLength: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.count > minLength {
            result.append(string)
        }
    }
    return result
}

// Return an array of strings sorted in alphabetical order
// sortStrings(strings: [] as [String]) == []
// sortStrings(strings: ["b", "a", "c"]) == ["a", "b", "c"]
// sortStrings(strings: ["b", "a", "C"]) == ["a", "b", "C"]
// sortStrings(strings: ["B", "a", "c", "A"]) == ["A", "a", "B", "c"]
func sortStrings(strings: [String]) -> [String] {
    return strings.sorted()
}

// Return an array of strings sorted in reverse alphabetical order
// reverseSortStrings(strings: [] as [String]) == []
// reverseSortStrings(strings: ["b", "a", "c"]) == ["c", "b", "a"]
// reverseSortStrings(strings: ["b", "a", "C"]) == ["C", "b", "a"]
// reverseSortStrings(strings: ["B", "a", "c", "A"]) == ["A", "c", "B", "a"]
func reverseSortStrings(strings: [String]) -> [String] {
    return strings.sorted(by: >)
}

// Return an array of strings with duplicates removed
// removeDuplicates(strings: [] as [String]) == []
// removeDuplicates(strings: ["a", "b", "c"]) == ["a", "b", "c"]
// removeDuplicates(strings: ["a", "b", "a", "c"]) == ["a", "b", "c"]
// removeDuplicates(strings: ["a", "b", "A", "a", "c", "C", "c"]) == ["a", "b", "A", "c"]
func removeDuplicates(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        if!result.contains(string) {
            result.append(string)
        }
    }
    return result
}

// Return an array of strings with duplicates removed, but only include strings that are at least minLength in length
// filterByMinLengthAndUnique(strings: [] as [String], minLength: 5) == []
// filterByMinLengthAndUnique(strings: ["a", "b", "c"], minLength: 5) == ["a", "b", "

func concatenate(strings: [String]) -> String {
    var result = ""
    for string in strings {
        result += string
    }
    return result
}

func reverse(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        result.insert(string, at: 0)
    }
    return result
}

func firstThreeCharacters(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        if string.count > 3 {
            result.append(string[0...2])
        } else {
            result.append(string)
        }
    }
    return result
}

func removeWhitespace(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        var newString = ""
        for char in string {
            if!char.isWhitespace {
                newString += String(char)
            }
        }
        result.append(newString)
    }
    return result
}

func removePunctuation(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        var newString = ""
        for char in string {
            if!char.isPunctuation {
                newString += String(char)
            }
        }
        result.append(newString)
    }
    return result
}

func removeVowels(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        var newString = ""
        for char in string {
            if!"AEIOUYaeiouy".contains(char) {
                newString += String(char)
            }
        }
        result.append(newString)
    }
    return result
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    var result = ""
    for string in strings {
        result += string
    }
    return result
}

// Reverse the order of an array of strings
// reverse(strings: [] as [String]) == []
// reverse(strings: ["a", "b", "c"]) == ["c", "b", "a"]
func reverse(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        result.insert(string, at: 0)
    }
    return result
}

// Return an array of strings containing the first 3 characters of each string
// firstThreeCharacters(strings: [] as [String]) == []
// firstThreeCharacters(strings: ["a", "ab", "abc"]) == ["a", "ab", "abc"]
func firstThreeCharacters(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        if string.count > 3 {
            result.append(string[0...2])
        } else {
            result.append(string)
        }
    }
    return result
}

// Return an array of strings with all whitespace characters removed
// removeWhitespace(strings: [] as [String]) == []
// removeWhitespace(strings: ["a", "b", "c"]) == ["a", "b", "c"]
// removeWhitespace(strings: ["a", "b", "c", " "]) == ["a", "b", "c"]
// removeWhitespace(strings: ["a", "b", "c", " ", " "]) == ["a", "b", "c"]
// removeWhitespace(strings: ["a", "b", "c", " ", " ", " "]) == ["a", "b", "c"]
func removeWhitespace(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        var newString = ""
        for char in string {
            if!char.isWhitespace {
                newString += String(char)
            }
        }
        result.append(newString)
    }
    return result
}

// Return an array of strings with all punctuation marks and special characters removed
// removePunctuation(strings: [] as [String]) == []
// removePunctuation(strings: ["a", "b", "c"]) == ["a", "b", "c"]
// removePunctuation(strings: ["a", "b", "c", "!"]) == ["a", "b", "c", "!"]
// removePunctuation(strings: ["a", "b", "c", "!", "@"]) == ["a", "b", "c", "!"]
// removePunctuation(strings: ["a", "b", "c", "!", "@", "#"]) == ["a", "b", "c", "!"]
func removePunctuation(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        var newString = ""
        for char in string {
            if!char.isPunctuation {
                newString += String(char)
            }
        }
        result.append(newString)
    }
    return result
}

// Return an array of strings with all vowels removed
// removeVowels(strings: [] as [String]) == []
// removeVowels(strings: ["a", "b", "c"]) == ["b", "c"]
// removeVowels(strings: ["a", "e", "i", "o", "u", "y"]) == []
// removeVowels(strings: ["a", "e", "i", "o", "u", "y", "A", "E", "I", "O", "U", "Y"]) == []
func removeVowels(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        var newString = ""
        for char in string {
            if!"AEIOUYaeiouy".contains(char) {
                newString += String(char)
            }
        }
        result.append(newString)
    }
    return result
}

// Return an array of strings with duplicates removed
// removeDuplicates(strings: [] as [String]) == []
// removeDuplicates(strings: ["a", "b", "c"]) == ["a", "b", "c"]
// removeDuplicates(strings: ["a", "b", "c", "a"]) == ["a", "b", "c"]
// removeDuplicates(strings: ["a",

func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

func reverse(strings: [String]) -> [String] {
    return strings.reversed()
}

func first(strings: [String], n: Int) -> [String] {
    return Array(strings.prefix(n))
}

func rest(strings: [String], n: Int) -> [String] {
    return Array(strings.dropFirst(n))
}

func butLast(strings: [String], n: Int) -> [String] {
    return Array(strings.dropLast(n))
}

func removeAt(strings: [String], indexes: [Int]) -> [String] {
    var mutableStrings = strings
    indexes.forEach { index in
        mutableStrings.remove(at: index)
    }
    return mutableStrings
}

func remove(strings: [String], stringsToRemove: [String]) -> [String] {
    var mutableStrings = strings
    stringsToRemove.forEach { string in
        mutableStrings.removeAll(where: { $0 == string })
    }
    return mutableStrings
}

func reverseInPlace(strings: [String]) -> [String] {
    var mutableStrings = strings
    mutableStrings.reverse()
    return mutableStrings
}

func capitalizeInPlace(strings: [String]) -> [String] {
    var mutableStrings = strings
    mutableStrings.forEach { string in
        mutableStrings[strings.firstIndex(of: string)!] = string.capitalized
    }
    return mutableStrings
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

// Reverse the order of an array of strings
// reverse(strings: [] as [String]) == []
// reverse(strings: ["a", "b", "c"]) == ["c", "b", "a"]
func reverse(strings: [String]) -> [String] {
    return strings.reversed()
}

// Return an array of strings containing the first n strings
// first(strings: [] as [String], n: 0) == []
// first(strings: ["a", "b", "c"], n: 2) == ["a", "b"]
// first(strings: ["a", "b", "c"], n: 4) == ["a", "b", "c"]
func first(strings: [String], n: Int) -> [String] {
    return Array(strings.prefix(n))
}

// Return an array of strings containing all but the first n strings
// rest(strings: [] as [String], n: 0) == []
// rest(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// rest(strings: ["a", "b", "c"], n: 3) == []
func rest(strings: [String], n: Int) -> [String] {
    return Array(strings.dropFirst(n))
}

// Return an array of strings containing all but the last n strings
// butLast(strings: [] as [String], n: 0) == []
// butLast(strings: ["a", "b", "c"], n: 1) == ["a", "b"]
// butLast(strings: ["a", "b", "c"], n: 3) == []
func butLast(strings: [String], n: Int) -> [String] {
    return Array(strings.dropLast(n))
}

// Return an array of strings containing all strings but the ones at the specified indexes
// removeAt(strings: [] as [String], indexes: []) == []
// removeAt(strings: ["a", "b", "c", "d", "e"], indexes: [0, 2, 4]) == ["b", "d"]
func removeAt(strings: [String], indexes: [Int]) -> [String] {
    var mutableStrings = strings
    indexes.forEach { index in
        mutableStrings.remove(at: index)
    }
    return mutableStrings
}

// Return an array of strings containing all strings but the specified strings
// remove(strings: [] as [String], stringsToRemove: []) == []
// remove(strings: ["a", "b", "c", "d", "e"], stringsToRemove: ["a", "e"]) == ["b", "c", "d"]
func remove(strings: [String], stringsToRemove: [String]) -> [String] {
    var mutableStrings = strings
    stringsToRemove.forEach { string in
        mutableStrings.removeAll(where: { $0 == string })
    }
    return mutableStrings
}

// Return an array of strings containing the original strings in reverse order
// reverseInPlace(strings: [] as [String]) == []
// reverseInPlace(strings: ["a", "b", "c"]) == ["c", "b", "a"]
func reverseInPlace(strings: [String]) -> [String] {
    var mutableStrings = strings
    mutableStrings.reverse()
    return mutableStrings
}

// Return an array of strings containing the original strings with each string capitalized
// capitalizeInPlace(strings: [] as [String]) == []
// capitalizeInPlace(strings: ["a", "b", "c"]) == ["A", "B", "C"]
func capitalizeInPlace(strings: [String]) -> [String] {
    var mutableStrings = strings
    mutableStrings.forEach { string in
        mutableStrings[strings.firstIndex(of: string)!] = string.capitalized
    }
    return mutableStrings
}

// Return an array of strings containing the original strings with each string reversed and capitalized
// mapInPlace(strings: [] as [String], transform: (String) -> String) == []
// mapInPlace(strings: ["a", "b", "c"], transform: { string in string.capitalized + string.reversed() }) == ["Aa", "Bb", "Cc"]
func mapInPlace(strings: [String], transform: (String) -> String) -> [String] {
    var mutableStrings = strings
    mutableStrings.enumerated().forEach

func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

func reverse(strings: [String]) -> [String] {
    return strings.reversed()
}

func first(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<min(n, strings.count)])
}

func rest(strings: [String], n: Int) -> [String] {
    return Array(strings[n..<strings.count])
}

func initial(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<max(0, strings.count - n)])
}

func withoutLast(strings: [String], n: Int) -> [String] {
    return Array(strings[1..<max(1, strings.count - n)])
}

func withoutFirst(strings: [String], n: Int) -> [String] {
    return Array(strings[n..<strings.count])
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

// Reverse the order of an array of strings
// reverse(strings: [] as [String]) == []
// reverse(strings: ["a", "b", "c"]) == ["c", "b", "a"]
func reverse(strings: [String]) -> [String] {
    return strings.reversed()
}

// Return an array of strings containing the first n strings
// first(strings: [] as [String], n: 1) == []
// first(strings: ["a", "b", "c"], n: 2) == ["a", "b"]
// first(strings: ["a", "b", "c"], n: 3) == ["a", "b", "c"]
// first(strings: ["a", "b", "c"], n: 4) == ["a", "b", "c"]
func first(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<min(n, strings.count)])
}

// Return an array of strings containing all strings except the first n
// rest(strings: [] as [String], n: 1) == []
// rest(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// rest(strings: ["a", "b", "c"], n: 2) == ["c"]
// rest(strings: ["a", "b", "c"], n: 3) == []
func rest(strings: [String], n: Int) -> [String] {
    return Array(strings[n..<strings.count])
}

// Return an array of strings containing all strings except the last n
// initial(strings: [] as [String], n: 1) == []
// initial(strings: ["a", "b", "c"], n: 1) == ["a", "b"]
// initial(strings: ["a", "b", "c"], n: 2) == ["a"]
// initial(strings: ["a", "b", "c"], n: 3) == []
func initial(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<max(0, strings.count - n)])
}

// Return an array of strings containing all strings except the first and last n
// withoutLast(strings: [] as [String], n: 1) == []
// withoutLast(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// withoutLast(strings: ["a", "b", "c"], n: 2) == ["a", "b"]
// withoutLast(strings: ["a", "b", "c"], n: 3) == ["a"]
func withoutLast(strings: [String], n: Int) -> [String] {
    return Array(strings[1..<max(1, strings.count - n)])
}

// Return an array of strings containing all strings except the first and first n
// withoutFirst(strings: [] as [String], n: 1) == []
// withoutFirst(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// withoutFirst(strings: ["a", "b", "c"], n: 2) == ["c"]
// withoutFirst(strings: ["a", "b", "c"], n: 3) == []
func withoutFirst(strings: [String], n: Int) -> [String] {
    return Array(strings[n..<strings.count])
}

// Return an array of strings containing all strings in reverse order
// reverse(strings: [] as [String]) == []
// reverse(strings: ["a", "b", "c"]) == ["c", "b", "a"]
func reverse(strings: [String]) -> [String] {
    return strings.reversed()
}

// Return an array of strings containing all strings in reverse order,
// but without any duplicates
// unique(strings: [] as [String]) == []
// unique(strings: ["a", "b", "c"]) == ["c", "b", "a"]
// unique(strings: ["a", "b", "c", "a"]) == ["c", "b", "a"]
func unique(strings: [String]) -> [String] {
    var uniqueStrings = [String]()
    for string in strings {
        if!uniqueStrings.contains(string)

func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

func reverse(strings: [String]) -> [String] {
    return strings.reversed()
}

func first(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<Swift.min(n, strings.count)])
}

func rest(strings: [String], n: Int) -> [String] {
    return Array(strings[Swift.max(0, n)..<strings.count])
}

func initial(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<Swift.max(0, strings.count - n)])
}

func compact(strings: [String], n: Int) -> [String] {
    return Array(strings[Swift.max(0, n)..<Swift.min(strings.count - n, strings.count)])
}

func filterLongStrings(strings: [String], minLength: Int) -> [String] {
    return strings.filter { $0.count > minLength }
}

func filterShortStrings(strings: [String], maxLength: Int) -> [String] {
    return strings.filter { $0.count < maxLength }
}

func unique(strings: [String]) -> [String] {
    return Array(Set(strings))
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

// Reverse the order of an array of strings
// reverse(strings: [] as [String]) == []
// reverse(strings: ["a", "b", "c"]) == ["c", "b", "a"]
func reverse(strings: [String]) -> [String] {
    return strings.reversed()
}

// Return an array of strings containing the first n strings
// first(strings: [] as [String], n: 0) == []
// first(strings: ["a", "b", "c"], n: 2) == ["a", "b"]
// first(strings: ["a", "b", "c"], n: 42) == ["a", "b", "c"]
func first(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<Swift.min(n, strings.count)])
}

// Return an array of strings containing all strings except the first n
// rest(strings: [] as [String], n: 0) == []
// rest(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// rest(strings: ["a", "b", "c"], n: 42) == []
func rest(strings: [String], n: Int) -> [String] {
    return Array(strings[Swift.max(0, n)..<strings.count])
}

// Return an array of strings containing all strings except the last n
// initial(strings: [] as [String], n: 0) == []
// initial(strings: ["a", "b", "c"], n: 1) == ["a", "b"]
// initial(strings: ["a", "b", "c"], n: 42) == ["a", "b", "c"]
func initial(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<Swift.max(0, strings.count - n)])
}

// Return an array of strings containing all strings except the first and last n
// compact(strings: [] as [String], n: 0) == []
// compact(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// compact(strings: ["a", "b", "c"], n: 2) == ["a", "b", "c"]
func compact(strings: [String], n: Int) -> [String] {
    return Array(strings[Swift.max(0, n)..<Swift.min(strings.count - n, strings.count)])
}

// Return an array of strings containing all strings longer than the given length
// filterLongStrings(strings: [] as [String], minLength: 0) == []
// filterLongStrings(strings: ["a", "ab", "abc"], minLength: 2) == ["ab", "abc"]
// filterLongStrings(strings: ["a", "ab", "abc"], minLength: 4) == ["ab", "abc"]
func filterLongStrings(strings: [String], minLength: Int) -> [String] {
    return strings.filter { $0.count > minLength }
}

// Return an array of strings containing all strings shorter than the given length
// filterShortStrings(strings: [] as [String], maxLength: 0) == []
// filterShortStrings(strings: ["a", "ab", "abc"], maxLength: 2) == ["a"]
// filterShortStrings(strings: ["a", "ab", "abc"], maxLength: 4) == ["a", "ab"]
func filterShortStrings(strings: [String], maxLength: Int) -> [String] {
    return strings.filter { $0.count < maxLength }
}

// Return an array of strings containing only strings with unique characters
// unique(strings: [] as [String]) == []
// unique(strings: ["a", "b", "c"]) == ["a", "b", "c"]
// unique(strings: ["a", "b", "ba", "c", "ca"]) == ["a", "b", "c", "ca"]
func unique(strings: [String]) -> [String] {
    return Array(Set(strings))
}

// Return an array of strings containing only strings with unique characters,
// preserving order of original strings
// uniquePreservingOrder(strings: [] as [String]) == []
//

func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

func reverse(strings: [String]) -> [String] {
    return strings.reversed()
}

func first(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<min(n, strings.count)])
}

func rest(strings: [String], n: Int) -> [String] {
    return Array(strings[n..<strings.count])
}

func initial(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<max(0, strings.count - n)])
}

func compact(strings: [String], n: Int) -> [String] {
    return Array(strings[n..<strings.count-n])
}

func filterLongerThan(strings: [String], n: Int) -> [String] {
    return strings.filter { $0.count > n }
}

func filterShorterThan(strings: [String], n: Int) -> [String] {
    return strings.filter { $0.count < n }
}

```swift
// Concatenate array of strings into a single string
// concatenate(strings: [] as [String]) == ""
// concatenate(strings: ["a", "b", "c"]) == "abc"
func concatenate(strings: [String]) -> String {
    return strings.reduce("", +)
}

// Reverse the order of an array of strings
// reverse(strings: [] as [String]) == []
// reverse(strings: ["a", "b", "c"]) == ["c", "b", "a"]
func reverse(strings: [String]) -> [String] {
    return strings.reversed()
}

// Return an array of strings containing the first n strings
// first(strings: [] as [String], n: 1) == []
// first(strings: ["a", "b", "c"], n: 2) == ["a", "b"]
// first(strings: ["a", "b", "c"], n: 3) == ["a", "b", "c"]
// first(strings: ["a", "b", "c"], n: 4) == ["a", "b", "c"]
func first(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<min(n, strings.count)])
}

// Return an array of strings containing all strings except the first n
// rest(strings: [] as [String], n: 1) == []
// rest(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// rest(strings: ["a", "b", "c"], n: 2) == ["c"]
// rest(strings: ["a", "b", "c"], n: 3) == []
func rest(strings: [String], n: Int) -> [String] {
    return Array(strings[n..<strings.count])
}

// Return an array of strings containing all strings except the last n
// initial(strings: [] as [String], n: 1) == []
// initial(strings: ["a", "b", "c"], n: 1) == ["a", "b"]
// initial(strings: ["a", "b", "c"], n: 2) == ["a"]
// initial(strings: ["a", "b", "c"], n: 3) == []
func initial(strings: [String], n: Int) -> [String] {
    return Array(strings[0..<max(0, strings.count - n)])
}

// Return an array of strings containing all strings except the first and last n
// compact(strings: [] as [String], n: 1) == []
// compact(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// compact(strings: ["a", "b", "c"], n: 2) == ["a", "b"]
// compact(strings: ["a", "b", "c"], n: 3) == ["a"]
func compact(strings: [String], n: Int) -> [String] {
    return Array(strings[n..<strings.count-n])
}

// Return an array of strings containing all strings longer than n characters
// filterLongerThan(strings: [] as [String], n: 1) == []
// filterLongerThan(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// filterLongerThan(strings: ["a", "b", "c"], n: 2) == ["b", "c"]
// filterLongerThan(strings: ["a", "b", "c"], n: 3) == ["a", "b", "c"]
func filterLongerThan(strings: [String], n: Int) -> [String] {
    return strings.filter { $0.count > n }
}

// Return an array of strings containing all strings shorter than n characters
// filterShorterThan(strings: [] as [String], n: 1) == []
// filterShorterThan(strings: ["a", "b", "c"], n: 1) == ["a"]
// filterShorterThan(strings: ["a", "b", "c"], n: 2) == ["a", "b"]
// filterShorterThan(strings: ["a", "b", "c"], n: 3) == ["a", "b", "c"]
func filterShorterThan(strings: [String], n: Int) -> [String] {
    return strings.filter { $0.count < n }
}

// Return an array of strings containing all strings with the given length
// filterByLength(strings: [] as [String

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

func filterBySuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasSuffix(suffix) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterByRegex(strings: [String], regex: String) -> [String] {
    var result = [String]()
    for string in strings {
        if let _ = string.range(of: regex, options:.regularExpression) {
            result.append(string)
        }
    }
    return result
}

func filterByPrefixAndSuffixAndSubstring(strings: [String], prefix: String, suffix: String, substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) && string.hasSuffix(suffix) && string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterByPrefixAndSuffixAndSubstringAndRegex(strings: [String], prefix: String, suffix: String, substring: String, regex: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) && string.hasSuffix(suffix) && string.contains(substring) && string.range(of: regex, options:.regularExpression)!= nil {
            result.append(string)
        }
    }
    return result
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that end with a given suffix.
// filterBySuffix(strings: [] as [String], suffix: "a") == [] as [String]
// filterBySuffix(strings: ["abc", "bcd", "cde", "array"], suffix: "a") == ["bcd", "cde"]
func filterBySuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasSuffix(suffix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain a given substring.
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["abc", "bcd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that match a given regular expression.
// filterByRegex(strings: [] as [String], regex: "a") == [] as [String]
// filterByRegex(strings: ["abc", "bcd", "cde", "array"], regex: "[a-z]+") == ["abc", "bcd", "cde"]
func filterByRegex(strings: [String], regex: String) -> [String] {
    var result = [String]()
    for string in strings {
        if let _ = string.range(of: regex, options:.regularExpression) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings by first removing all strings that do not start with a given prefix,
// then removing all strings that do not end with a given suffix, and finally removing all strings that do not contain
// a given substring.
// filterByPrefixAndSuffixAndSubstring(strings: [] as [String], prefix: "a", suffix: "a", substring: "a") == [] as [String]
// filterByPrefixAndSuffixAndSubstring(strings: ["abc", "bcd", "cde", "array"], prefix: "a", suffix: "a", substring: "a") == ["abc", "array"]
func filterByPrefixAndSuffixAndSubstring(strings: [String], prefix: String, suffix: String, substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) && string.hasSuffix(suffix) && string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings by first removing all strings that do not start with a given prefix,
// then removing all strings that do not end with a given suffix, and finally removing all strings that do not contain
// a given substring, while also removing any strings that do not match a given regular expression.
// filterByPrefixAndSuffixAndSubstringAndRegex(strings: [] as [String], prefix: "a", suffix: "a", substring: "a", regex: "[a-z]+") == [] as [String]
// filterByPrefixAndSuffixAndSubstringAndRegex(strings: ["abc", "bcd", "cde", "array"], prefix: "a", suffix: "a", substring: "a", regex: "[a-z]+") == ["abc", "array"]
func filterByPrefixAndSuffixAndSubstringAndRegex(strings: [String], prefix: String, suffix: String, substring: String, regex: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) && string.hasSuffix(suffix) && string.contains(substring) && string.range(of: regex, options:.regularExpression)!= nil {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings by first removing all strings that do not start with a given prefix,
// then removing all strings that do not end with a given suffix, and finally removing all strings that

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstringInReverse(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.reversed().contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterByCharacter(strings: [String], character: Character) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(character) {
            result.append(string)
        }
    }
    return result
}

func filterByCharacterAtIndex(strings: [String], character: Character, index: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.indices.contains(index) && string[string.index(string.startIndex, offsetBy: index)] == character {
            result.append(string)
        }
    }
    return result
}

func filterByPrefixAndSubstring(strings: [String], prefix: String, substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) && string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterByPrefixAndSubstringInReverse(strings: [String], prefix: String, substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) && string.reversed().contains(substring) {
            result.append(string)
        }
    }
    return result
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain a given substring.
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["abc", "bcd", "cde"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain a given substring in reverse.
// filterBySubstringInReverse(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringInReverse(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["cde", "array"]
func filterBySubstringInReverse(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.reversed().contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain a given character.
// filterByCharacter(strings: [] as [String], character: "a") == [] as [String]
// filterByCharacter(strings: ["abc", "bcd", "cde", "array"], character: "a") == ["abc", "bcd", "cde", "array"]
func filterByCharacter(strings: [String], character: Character) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(character) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain a given character at a given index.
// filterByCharacterAtIndex(strings: [] as [String], character: "a", index: 0) == [] as [String]
// filterByCharacterAtIndex(strings: ["abc", "bcd", "cde", "array"], character: "a", index: 0) == ["abc", "array"]
func filterByCharacterAtIndex(strings: [String], character: Character, index: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.indices.contains(index) && string[string.index(string.startIndex, offsetBy: index)] == character {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that start with a given prefix and contain a given substring.
// filterByPrefixAndSubstring(strings: [] as [String], prefix: "a", substring: "b") == [] as [String]
// filterByPrefixAndSubstring(strings: ["abc", "bcd", "cde", "array"], prefix: "a", substring: "b") == ["abc"]
func filterByPrefixAndSubstring(strings: [String], prefix: String, substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) && string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that start with a given prefix and contain a given substring in reverse.
// filterByPrefixAndSubstringInReverse(strings: [] as [String], prefix: "a", substring: "b") == [] as [String]
// filterByPrefixAndSubstringInReverse(strings: ["abc", "bcd", "cde", "array"], prefix: "a", substring: "b") == ["cde"]
func filterByPrefixAndSubstringInReverse(strings: [String], prefix: String, substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) && string.reversed().contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that start with a given prefix and contain a given character.
// filterByPrefixAndCharacter(

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) }
}

func filterByDivisor(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

func sum(numbers: [Int]) -> Int {
    return numbers.reduce(0, +)
}

func average(numbers: [Int]) -> Double {
    return Double(sum(numbers: numbers)) / Double(numbers.count)
}

func median(numbers: [Int]) -> Double? {
    let sortedNumbers = numbers.sorted()
    let count = sortedNumbers.count
    if count % 2 == 0 {
        let midIndex = count / 2
        return Double(sortedNumbers[midIndex - 1] + sortedNumbers[midIndex]) / 2.0
    } else {
        let midIndex = count / 2
        return Double(sortedNumbers[midIndex])
    }
}

func product(numbers: [Int]) -> Int {
    return numbers.reduce(1, *)
}

func mostCommon(numbers: [Int]) -> Int? {
    return numbers.reduce(into: [:]) { counts, number in
        counts[number, default: 0] += 1
    }.max { $0.value < $1.value }?.key
}

func longest(strings: [String]) -> String? {
    return strings.reduce(into: "") { currentLongest, string in
        if currentLongest.count < string.count {
            currentLongest = string
        }
    }
}

func shortest(strings: [String]) -> String? {
    return strings.reduce(into: "") { currentShortest, string in
        if currentShortest.count == 0 || string.count < currentShortest.count {
            currentShortest = string
        }
    }
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) }
}

// Filter an input array of integers only for ones that are divisible by a given divisor.
// filterByDivisor(numbers: [] as [Int], divisor: 2) == [] as [Int]
// filterByDivisor(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 2) == [2, 4, 6, 8, 10]
func filterByDivisor(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

// Return the sum of all integers in an input array.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 55
func sum(numbers: [Int]) -> Int {
    return numbers.reduce(0, +)
}

// Return the average of all integers in an input array.
// average(numbers: [] as [Int]) == 0.0
// average(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 5.5
func average(numbers: [Int]) -> Double {
    return Double(sum(numbers: numbers)) / Double(numbers.count)
}

// Return the median of all integers in an input array.
// median(numbers: [] as [Int]) == nil
// median(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 5.5
func median(numbers: [Int]) -> Double? {
    let sortedNumbers = numbers.sorted()
    let count = sortedNumbers.count
    if count % 2 == 0 {
        let midIndex = count / 2
        return Double(sortedNumbers[midIndex - 1] + sortedNumbers[midIndex]) / 2.0
    } else {
        let midIndex = count / 2
        return Double(sortedNumbers[midIndex])
    }
}

// Return the product of all integers in an input array.
// product(numbers: [] as [Int]) == 1
// product(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 3628800
func product(numbers: [Int]) -> Int {
    return numbers.reduce(1, *)
}

// Return the most common element in an input array.
// mostCommon(numbers: [] as [Int]) == nil
// mostCommon(numbers: [1, 1, 2, 3, 4, 4, 4, 5, 5, 5, 5]) == 5
func mostCommon(numbers: [Int]) -> Int? {
    return numbers.reduce(into: [:]) { counts, number in
        counts[number, default: 0] += 1
    }.max { $0.value < $1.value }?.key
}

// Return the longest string in an input array.
// longest(strings: [] as [String]) == nil
// longest(strings: ["abc", "bcd", "cde", "array"]) == "array"
func longest(strings: [String]) -> String? {
    return strings.reduce(into: "") { currentLongest, string in
        if currentLongest.count < string.count {
            currentLongest = string
        }
    }
}

// Return the shortest string in an input array.
// shortest(strings: [] as [String]) == nil
// shortest(strings: ["abc", "bcd", "cde", "array"]) == "abc"
func shortest(strings: [String]) -> String? {
    return strings.reduce(into: "") { currentShortest, string in
        if currentShortest.count == 0 || string.count < currentShortest.count {
            currentShortest = string
        }
    }
}

// Return the second longest string in an input array.
// secondLongest(strings: [] as [String]) == nil
// secondLongest(strings: ["abc", "bcd", "

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

func filterBySuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasSuffix(suffix) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterByRegex(strings: [String], regex: String) -> [String] {
    var result = [String]()
    for string in strings {
        if let _ = string.range(of: regex, options:.regularExpression) {
            result.append(string)
        }
    }
    return result
}

func longestLength(strings: [String]) -> Int {
    var longest = 0
    for string in strings {
        if string.count > longest {
            longest = string.count
        }
    }
    return longest
}

func shortestLength(strings: [String]) -> Int {
    var shortest = Int.max
    for string in strings {
        if string.count < shortest {
            shortest = string.count
        }
    }
    return shortest
}

func sumOfLengths(strings: [String]) -> Int {
    var sum = 0
    for string in strings {
        sum += string.count
    }
    return sum
}

func averageLength(strings: [String]) -> Double {
    return Double(sumOfLengths(strings: strings)) / Double(strings.count)
}

func countStrings(strings: [String], prefix: String) -> Int {
    var count = 0
    for string in strings {
        if string.hasPrefix(prefix) {
            count += 1
        }
    }
    return count
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that end with a given suffix.
// filterBySuffix(strings: [] as [String], suffix: "a") == [] as [String]
// filterBySuffix(strings: ["abc", "bcd", "cde", "array"], suffix: "a") == ["bcd", "cde"]
func filterBySuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasSuffix(suffix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain a given substring.
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["abc", "bcd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that match a given regular expression.
// filterByRegex(strings: [] as [String], regex: "a") == [] as [String]
// filterByRegex(strings: ["abc", "bcd", "cde", "array"], regex: "[a-z]+") == ["abc", "bcd", "cde"]
func filterByRegex(strings: [String], regex: String) -> [String] {
    var result = [String]()
    for string in strings {
        if let _ = string.range(of: regex, options:.regularExpression) {
            result.append(string)
        }
    }
    return result
}

// Return the length of the longest string in an input array.
// longestLength(strings: [] as [String]) == 0
// longestLength(strings: ["abc", "bcd", "cde", "array"]) == 6
func longestLength(strings: [String]) -> Int {
    var longest = 0
    for string in strings {
        if string.count > longest {
            longest = string.count
        }
    }
    return longest
}

// Return the length of the shortest string in an input array.
// shortestLength(strings: [] as [String]) == 0
// shortestLength(strings: ["abc", "bcd", "cde", "array"]) == 3
func shortestLength(strings: [String]) -> Int {
    var shortest = Int.max
    for string in strings {
        if string.count < shortest {
            shortest = string.count
        }
    }
    return shortest
}

// Return the sum of the lengths of all strings in an input array.
// sumOfLengths(strings: [] as [String]) == 0
// sumOfLengths(strings: ["abc", "bcd", "cde", "array"]) == 20
func sumOfLengths(strings: [String]) -> Int {
    var sum = 0
    for string in strings {
        sum += string.count
    }
    return sum
}

// Return the average length of all strings in an input array.
// averageLength(strings: [] as [String]) == 0
// averageLength(strings: ["abc", "bcd", "cde", "array"]) == 4.5
func averageLength(strings: [String]) -> Double {
    return Double(sumOfLengths(strings: strings)) / Double(strings.count)
}

// Return the number of strings that start with a given prefix.
// countStrings(strings: [] as [String], prefix: "a") == 0
// countStrings(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == 2
func countStrings(strings: [String], prefix: String) -> Int {
    var count = 0
    for string in strings {
        if string.hasPrefix(prefix) {
            count += 1
        }
    }
    return count
}

// Return the number of strings that end with a given suffix.
// countStrings(strings: [] as [String], suffix: "a")

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

func filterByDivisor(numbers: [Int], divisor: Int) -> [Int] {
    var result = [Int]()
    for number in numbers {
        if number % divisor == 0 {
            result.append(number)
        }
    }
    return result
}

func combineArrays(first: [String], second: [Int]) -> [(value: Any, index: Int)] {
    var result = [(value: Any, index: Int)]()
    for (index, value) in first.enumerated() {
        result.append((value, index))
    }
    for (index, value) in second.enumerated() {
        result.append((value, index))
    }
    return result
}

func sortDescending(strings: [String], integers: [Int]) -> [String] {
    var result = strings
    result.sort(by: { $0.lowercased() > $1.lowercased() })
    return result
}

func groupByFirstCharacter(strings: [String]) -> [String: [String]] {
    var result = [String: [String]]()
    for string in strings {
        let firstCharacter = string.lowercased().prefix(1)
        if result[firstCharacter] == nil {
            result[firstCharacter] = [String]()
        }
        result[firstCharacter]!.append(string)
    }
    return result
}

func getSecondAndThird(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        if!string.contains("1") &&!string.contains("2") &&!string.contains("3") {
            if string.count > 2 {
                result.append(string)
            }
        }
    }
    return result
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of integers only for ones that are divisible by a given divisor.
// filterByDivisor(numbers: [] as [Int], divisor: 2) == [] as [Int]
// filterByDivisor(numbers: [1, 2, 3, 4, 5, 6], divisor: 2) == [2, 4, 6]
func filterByDivisor(numbers: [Int], divisor: Int) -> [Int] {
    var result = [Int]()
    for number in numbers {
        if number % divisor == 0 {
            result.append(number)
        }
    }
    return result
}

// Combine two input arrays of strings and integers into a single array,
// where each element is a tuple containing the input value and its index in the original array.
// combineArrays(first: [] as [String], second: [] as [Int]) == [] as [(value: Any, index: Int)]
// combineArrays(first: ["a", "b", "c"], second: [1, 2, 3]) == [("a", 0), ("b", 1), ("c", 2)]
func combineArrays(first: [String], second: [Int]) -> [(value: Any, index: Int)] {
    var result = [(value: Any, index: Int)]()
    for (index, value) in first.enumerated() {
        result.append((value, index))
    }
    for (index, value) in second.enumerated() {
        result.append((value, index))
    }
    return result
}

// Sort an input array of strings and integers in descending order,
// while ignoring the case of each string.
// sortDescending(strings: [] as [String], integers: [] as [Int]) == [] as [String]
// sortDescending(strings: ["A", "b", "C"], integers: [1, 2, 3]) == ["C", "b", "A"]
func sortDescending(strings: [String], integers: [Int]) -> [String] {
    var result = strings
    result.sort(by: { $0.lowercased() > $1.lowercased() })
    return result
}

// Group an input array of strings by their first character,
// while ignoring the case of each string.
// groupByFirstCharacter(strings: [] as [String]) == [:] as [String: [String]]
// groupByFirstCharacter(strings: ["A", "b", "C", "a", "B", "c"]) == ["A": ["A", "a"], "B": ["B"], "C": ["C", "c"]]
func groupByFirstCharacter(strings: [String]) -> [String: [String]] {
    var result = [String: [String]]()
    for string in strings {
        let firstCharacter = string.lowercased().prefix(1)
        if result[firstCharacter] == nil {
            result[firstCharacter] = [String]()
        }
        result[firstCharacter]!.append(string)
    }
    return result
}

// Get the second and third elements from an input array of strings,
// while ignoring any strings that contain numbers.
// getSecondAndThird(strings: [] as [String]) == [] as [String]
// getSecondAndThird(strings: ["abc", "123", "bcd", "efg", "1abc", "2def", "3ghi"]) == ["bcd", "efg"]
func getSecondAndThird(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        if!string.contains("1") &&!string.contains("2") &&!string.contains("3") {
            if string.count > 2 {
                result.append(string)
            }
        }
    }
    return result
}

// Get the longest string from an input array of strings,
// while ignoring any strings that contain numbers.
// getLongestString(strings: [] as [String]) == nil as String?
// getLongestString(strings: ["abc", "123", "bcd", "efg", "1abc", "2def", "3ghi"]) == "efg"
func getLongestString(strings: [String]) -> String? {
    var longest

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result: [String] = []
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

func filterBySuffix(strings: [String], suffix: String) -> [String] {
    var result: [String] = []
    for string in strings {
        if string.hasSuffix(suffix) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result: [String] = []
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterByRegex(strings: [String], regex: String) -> [String] {
    var result: [String] = []
    for string in strings {
        if let _ = string.range(of: regex, options:.regularExpression) {
            result.append(string)
        }
    }
    return result
}

func removeDuplicates(strings: [String]) -> [String] {
    var result: [String] = []
    for string in strings {
        if!result.contains(string) {
            result.append(string)
        }
    }
    return result
}

func removePrefix(strings: [String], prefix: String) -> [String] {
    var result: [String] = []
    for string in strings {
        result.append(string.replacingOccurrences(of: prefix, with: ""))
    }
    return result
}

func removeSuffix(strings: [String], suffix: String) -> [String] {
    var result: [String] = []
    for string in strings {
        result.append(string.replacingOccurrences(of: suffix, with: ""))
    }
    return result
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result: [String] = []
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that end with a given suffix.
// filterBySuffix(strings: [] as [String], suffix: "a") == [] as [String]
// filterBySuffix(strings: ["abc", "bcd", "cde", "array"], suffix: "e") == ["cde", "array"]
func filterBySuffix(strings: [String], suffix: String) -> [String] {
    var result: [String] = []
    for string in strings {
        if string.hasSuffix(suffix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain a given substring.
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["abc", "bcd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result: [String] = []
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that match a given regular expression.
// filterByRegex(strings: [] as [String], regex: "a") == [] as [String]
// filterByRegex(strings: ["abc", "bcd", "cde", "array"], regex: "[a-z]+") == ["abc", "bcd", "cde"]
func filterByRegex(strings: [String], regex: String) -> [String] {
    var result: [String] = []
    for string in strings {
        if let _ = string.range(of: regex, options:.regularExpression) {
            result.append(string)
        }
    }
    return result
}

// Return an array of strings with duplicates removed.
// removeDuplicates(strings: [] as [String]) == [] as [String]
// removeDuplicates(strings: ["abc", "bcd", "cde", "array", "abc"]) == ["abc", "bcd", "cde", "array"]
func removeDuplicates(strings: [String]) -> [String] {
    var result: [String] = []
    for string in strings {
        if!result.contains(string) {
            result.append(string)
        }
    }
    return result
}

// Return an array of strings with the specified prefix removed from each string.
// removePrefix(strings: [] as [String], prefix: "a") == [] as [String]
// removePrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["bc", "cd", "ce", "ray"]
func removePrefix(strings: [String], prefix: String) -> [String] {
    var result: [String] = []
    for string in strings {
        result.append(string.replacingOccurrences(of: prefix, with: ""))
    }
    return result
}

// Return an array of strings with the specified suffix removed from each string.
// removeSuffix(strings: [] as [String], suffix: "a") == [] as [String]
// removeSuffix(strings: ["abc", "bcd", "cde", "array"], suffix: "e") == ["ab", "bc", "cd", "ray"]
func removeSuffix(strings: [String], suffix: String) -> [String] {
    var result: [String] = []
    for string in strings {
        result.append(string.replacingOccurrences(of: suffix, with: ""))
    }
    return result
}

// Return an array of strings with the specified substring removed from each string.
// removeSubstring(strings: [] as [String], substring: "a") == [] as [String]
// removeSubstring(strings: ["abc", "bcd", "cde", "array", "abc"], substring: "a") == ["bc", "bcd", "cde", "ray"]
func removeSubstring(strings: [String], substring: String) -> [String] {
    var result: [String] = []
    for string in strings {
        result.append(string.replacingOccurrences(of: substring, with: ""))
    }
    return

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) }
}

func filterByDivisor(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

func sum(numbers: [Int]) -> Int {
    return numbers.reduce(0, +)
}

func average(numbers: [Int]) -> Double {
    return Double(sum(numbers: numbers)) / Double(numbers.count)
}

func median(numbers: [Int]) -> Double? {
    let sortedNumbers = numbers.sorted()
    let count = sortedNumbers.count
    if count == 0 {
        return nil
    }
    let middleIndex = count / 2
    if count % 2 == 0 {
        return Double(sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2.0
    } else {
        return Double(sortedNumbers[middleIndex])
    }
}

func mode(numbers: [Int]) -> Int? {
    let counts = Dictionary(grouping: numbers, by: { $0 }).mapValues { $0.count }
    let maxCount = counts.values.max()
    return counts.filter { $0.value == maxCount }.map { $0.key }.first
}

func product(numbers: [Int]) -> Int {
    return numbers.reduce(1, *)
}

func standardDeviation(numbers: [Int]) -> Double {
    let average = average(numbers: numbers)
    let squaredDifferences = numbers.map { pow(Double($0 - average), 2) }
    return sqrt(average(numbers: squaredDifferences))
}

func range(numbers: [Int]) -> Int {
    return numbers.max()! - numbers.min()!
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) }
}

// Filter an input array of integers only for ones that are divisible by a given divisor.
// filterByDivisor(numbers: [] as [Int], divisor: 2) == [] as [Int]
// filterByDivisor(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 2) == [2, 4, 6, 8, 10]
func filterByDivisor(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

// Return the sum of all integers in an input array.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 55
func sum(numbers: [Int]) -> Int {
    return numbers.reduce(0, +)
}

// Return the average of all integers in an input array.
// average(numbers: [] as [Int]) == 0.0
// average(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 5.5
func average(numbers: [Int]) -> Double {
    return Double(sum(numbers: numbers)) / Double(numbers.count)
}

// Return the median of all integers in an input array.
// median(numbers: [] as [Int]) == nil
// median(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 5.5
func median(numbers: [Int]) -> Double? {
    let sortedNumbers = numbers.sorted()
    let count = sortedNumbers.count
    if count == 0 {
        return nil
    }
    let middleIndex = count / 2
    if count % 2 == 0 {
        return Double(sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2.0
    } else {
        return Double(sortedNumbers[middleIndex])
    }
}

// Return the mode of all integers in an input array.
// mode(numbers: [] as [Int]) == nil
// mode(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 1
func mode(numbers: [Int]) -> Int? {
    let counts = Dictionary(grouping: numbers, by: { $0 }).mapValues { $0.count }
    let maxCount = counts.values.max()
    return counts.filter { $0.value == maxCount }.map { $0.key }.first
}

// Return the product of all integers in an input array.
// product(numbers: [] as [Int]) == 1
// product(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 3628800
func product(numbers: [Int]) -> Int {
    return numbers.reduce(1, *)
}

// Return the standard deviation of all integers in an input array.
// standardDeviation(numbers: [] as [Int]) == 0.0
// standardDeviation(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 2.87
func standardDeviation(numbers: [Int]) -> Double {
    let average = average(numbers: numbers)
    let squaredDifferences = numbers.map { pow(Double($0 - average), 2) }
    return sqrt(average(numbers: squaredDifferences))
}

// Return the range of all integers in an input array.
// range(numbers: [] as [Int]) == 0
// range(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 9
func range(numbers: [Int]) -> Int {
    return numbers.max()! - numbers.min()!
}

// Return the frequency count of each unique pair of

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstringInReverse(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.reversed().contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstringInAnyOrder(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstringInAnyOrderAndMinimumLength(strings: [String], substring: String, minLength: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) && string.count >= minLength {
            result.append(string)
        }
    }
    return result
}

func filterBySubstringInAnyOrderAndMinimumLengthAndCapitalLetter(strings: [String], substring: String, minLength: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) && string.count >= minLength && string.first!.isUppercase {
            result.append(string)
        }
    }
    return result
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that have a given substring.
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["abc", "bcd", "cde"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that have a given substring in reverse.
// filterBySubstringInReverse(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringInReverse(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["cde", "array"]
func filterBySubstringInReverse(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.reversed().contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that have a given substring in any order.
// filterBySubstringInAnyOrder(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstringInAnyOrder(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["abc", "bcd", "cde", "array"]
func filterBySubstringInAnyOrder(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that have a given substring in any order and are at least 3 characters long.
// filterBySubstringInAnyOrderAndMinimumLength(strings: [] as [String], substring: "a", minLength: 3) == [] as [String]
// filterBySubstringInAnyOrderAndMinimumLength(strings: ["abc", "bcd", "cde", "array"], substring: "a", minLength: 3) == ["abc", "array"]
func filterBySubstringInAnyOrderAndMinimumLength(strings: [String], substring: String, minLength: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) && string.count >= minLength {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that have a given substring in any order and are at least 3 characters long and have a capital letter.
// filterBySubstringInAnyOrderAndMinimumLengthAndCapitalLetter(strings: [] as [String], substring: "a", minLength: 3) == [] as [String]
// filterBySubstringInAnyOrderAndMinimumLengthAndCapitalLetter(strings: ["abc", "bcd", "cde", "array"], substring: "a", minLength: 3) == ["abc"]
func filterBySubstringInAnyOrderAndMinimumLengthAndCapitalLetter(strings: [String], substring: String, minLength: Int) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) && string.count >= minLength && string.first!.isUppercase {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that have a given substring in any order and are at least 3 characters long and have a capital letter.
// The filtered strings should also not contain any special characters.
// filterBySubstringInAnyOrderAndMinimumLengthAndNoSpecialCharacters(strings: [] as [String], substring: "a", minLength: 3) == [] as [String]
// filterBySubstringInAnyOrderAndMinimumLengthAndNoSpecialCharacters(strings: ["abc", "123", "!@#$", "bcd", "cde", "array"], substring: "a",

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

func filterBySuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasSuffix(suffix) {
            result.append(string)
        }
    }
    return result
}

func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

func filterByRegex(strings: [String], regex: String) -> [String] {
    var result = [String]()
    for string in strings {
        if let _ = string.range(of: regex, options:.regularExpression) {
            result.append(string)
        }
    }
    return result
}

func addPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(prefix + string)
    }
    return result
}

func addSuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string + suffix)
    }
    return result
}

func removeSubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string.replacingOccurrences(of: substring, with: ""))
    }
    return result
}

func removeWhitespace(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string.replacingOccurrences(of: " ", with: ""))
    }
    return result
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasPrefix(prefix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that end with a given suffix.
// filterBySuffix(strings: [] as [String], suffix: "a") == [] as [String]
// filterBySuffix(strings: ["abc", "bcd", "cde", "array"], suffix: "a") == ["bcd", "cde"]
func filterBySuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.hasSuffix(suffix) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that contain a given substring.
// filterBySubstring(strings: [] as [String], substring: "a") == [] as [String]
// filterBySubstring(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["abc", "bcd", "array"]
func filterBySubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        if string.contains(substring) {
            result.append(string)
        }
    }
    return result
}

// Filter an input array of strings only for ones that match a given regular expression.
// filterByRegex(strings: [] as [String], regex: "a") == [] as [String]
// filterByRegex(strings: ["abc", "bcd", "cde", "array"], regex: "[a-z]+") == ["abc", "bcd", "cde"]
func filterByRegex(strings: [String], regex: String) -> [String] {
    var result = [String]()
    for string in strings {
        if let _ = string.range(of: regex, options:.regularExpression) {
            result.append(string)
        }
    }
    return result
}

// Return a new array of strings with a given prefix added to each string.
// addPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// addPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["aabc", "abcd", "aacde", "aarray"]
func addPrefix(strings: [String], prefix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(prefix + string)
    }
    return result
}

// Return a new array of strings with a given suffix added to each string.
// addSuffix(strings: [] as [String], suffix: "a") == [] as [String]
// addSuffix(strings: ["abc", "bcd", "cde", "array"], suffix: "a") == ["abca", "bcda", "cdea", "arraya"]
func addSuffix(strings: [String], suffix: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string + suffix)
    }
    return result
}

// Return a new array of strings with a given substring removed from each string.
// removeSubstring(strings: [] as [String], substring: "a") == [] as [String]
// removeSubstring(strings: ["abc", "bcd", "cde", "array"], substring: "a") == ["bc", "cd", "ce", "r"]
func removeSubstring(strings: [String], substring: String) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string.replacingOccurrences(of: substring, with: ""))
    }
    return result
}

// Return a new array of strings with all whitespace characters removed from each string.
// removeWhitespace(strings: [] as [String]) == [] as [String]
// removeWhitespace(strings: ["abc", "bcd", "cde", "array"]) == ["abc", "bcd", "cde", "array"]
func removeWhitespace(strings: [String]) -> [String] {
    var result = [String]()
    for string in strings {
        result.append(string.replacingOccurrences(of: " ", with: ""))
    }
    return result
}

// Return a new array of strings with all punctuation characters removed from each string.
// removeP

func filterByPrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) }
}

func filterByDivisor(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

func filterByPrefixAndContainNumbers(strings: [String], integers: [Int], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) &&!integers.contains { $0.contains($0) } }
}

func convertStringsToIntegers(strings: [String]) -> [Int] {
    return strings.compactMap { Int($0) }
}

func convertIntegersToStrings(integers: [Int]) -> [String] {
    return integers.map { String($0) }
}

func filterEvenIntegers(strings: [String]) -> [Int] {
    return strings.compactMap { Int($0) }
       .filter { $0 % 2 == 0 }
}

func filterEvenStrings(integers: [Int]) -> [String] {
    return integers.map { String($0) }
       .filter { $0 % 2 == 0 }
}

```swift
// Filter an input array of strings only for ones that start with a given prefix.
// filterByPrefix(strings: [] as [String], prefix: "a") == [] as [String]
// filterByPrefix(strings: ["abc", "bcd", "cde", "array"], prefix: "a") == ["abc", "array"]
func filterByPrefix(strings: [String], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) }
}

// Filter an input array of integers only for ones that are divisible by a given divisor.
// filterByDivisor(numbers: [] as [Int], divisor: 2) == [] as [Int]
// filterByDivisor(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], divisor: 2) == [2, 4, 6, 8, 10]
func filterByDivisor(numbers: [Int], divisor: Int) -> [Int] {
    return numbers.filter { $0 % divisor == 0 }
}

// Filter an input array of strings and integers and return an array of strings that start with a given prefix,
// while ignoring any strings that contain numbers.
// filterByPrefixAndContainNumbers(strings: [] as [String], integers: [] as [Int], prefix: "a") == [] as [String]
// filterByPrefixAndContainNumbers(strings: ["abc", "bcd", "cde", "array"], integers: [1, 2, 3, 4], prefix: "a") == ["abc"]
func filterByPrefixAndContainNumbers(strings: [String], integers: [Int], prefix: String) -> [String] {
    return strings.filter { $0.hasPrefix(prefix) &&!integers.contains { $0.contains($0) } }
}

// Return an array of integers from a given input array of strings,
// where each string in the input array is converted to an integer and added to the result array.
// convertStringsToIntegers(strings: [] as [String]) == [] as [Int]
// convertStringsToIntegers(strings: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]) == [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
func convertStringsToIntegers(strings: [String]) -> [Int] {
    return strings.compactMap { Int($0) }
}

// Return an array of strings from a given input array of integers,
// where each integer in the input array is converted to a string and added to the result array.
// convertIntegersToStrings(integers: [] as [Int]) == [] as [String]
// convertIntegersToStrings(integers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]
func convertIntegersToStrings(integers: [Int]) -> [String] {
    return integers.map { String($0) }
}

// Return an array of integers from a given input array of strings,
// where each string in the input array is converted to an integer and added to the result array only if it is even.
// filterEvenIntegers(strings: [] as [String]) == [] as [Int]
// filterEvenIntegers(strings: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]) == [2, 4, 6, 8, 10]
func filterEvenIntegers(strings: [String]) -> [Int] {
    return strings.compactMap { Int($0) }
       .filter { $0 % 2 == 0 }
}

// Return an array of strings from a given input array of integers,
// where each integer in the input array is converted to a string and added to the result array only if it is even.
// filterEvenStrings(integers: [] as [Int]) == [] as [String]
// filterEvenStrings(integers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == ["2", "4", "6", "8", "10"]
func filterEvenStrings(integers: [Int]) -> [String] {
    return integers.map { String($0) }
       .filter { $0 % 2 == 0 }
}

// Return an array of integers from a given input array of strings,
//

func getPositive(l: [Int]) -> [Int] {
    return l.filter { $0 > 0 }
}

func getSum(l: [Int]) -> Int {
    return l.reduce(0, +)
}

func getProduct(l: [Int]) -> Int {
    return l.reduce(1, *)
}

func getMin(l: [Int]) -> Int {
    return l.min()?? 0
}

func getMax(l: [Int]) -> Int {
    return l.max()?? 0
}

func getPositiveCount(l: [Int]) -> Int {
    return l.filter { $0 > 0 }.count
}

func getNegativeCount(l: [Int]) -> Int {
    return l.filter { $0 < 0 }.count
}

func getZeroCount(l: [Int]) -> Int {
    return l.filter { $0 == 0 }.count
}

func getPositiveSum(l: [Int]) -> Int {
    return l.filter { $0 > 0 }.reduce(0, +)
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    return l.filter { $0 > 0 }
}

// Return the sum of all numbers in the array.
// getSum(l: [-1, 2, -4, 5, 6]) == 13
// getSum(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 145
func getSum(l: [Int]) -> Int {
    return l.reduce(0, +)
}

// Return the product of all numbers in the array.
// getProduct(l: [-1, 2, -4, 5, 6]) == -4
// getProduct(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -4350943039680
func getProduct(l: [Int]) -> Int {
    return l.reduce(1, *)
}

// Return the minimum number in the array.
// getMin(l: [-1, 2, -4, 5, 6]) == -1
// getMin(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -10
func getMin(l: [Int]) -> Int {
    return l.min()?? 0
}

// Return the maximum number in the array.
// getMax(l: [-1, 2, -4, 5, 6]) == 6
// getMax(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func getMax(l: [Int]) -> Int {
    return l.max()?? 0
}

// Return the number of positive numbers in the array.
// getPositiveCount(l: [-1, 2, -4, 5, 6]) == 3
// getPositiveCount(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 10
func getPositiveCount(l: [Int]) -> Int {
    return l.filter { $0 > 0 }.count
}

// Return the number of negative numbers in the array.
// getNegativeCount(l: [-1, 2, -4, 5, 6]) == 4
// getNegativeCount(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 5
func getNegativeCount(l: [Int]) -> Int {
    return l.filter { $0 < 0 }.count
}

// Return the number of zeros in the array.
// getZeroCount(l: [-1, 2, -4, 5, 6]) == 0
// getZeroCount(l: [0, 3, 0, 2, -3, 3, 9, 0, 123, 1, -10]) == 3
func getZeroCount(l: [Int]) -> Int {
    return l.filter { $0 == 0 }.count
}

// Return the sum of all positive numbers in the array.
// getPositiveSum(l: [-1, 2, -4, 5, 6]) == 0
// getPositiveSum(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 15
func getPositiveSum(l: [Int]) -> Int {
    return l.filter { $0 > 0 }.reduce(0, +)
}

// Return the sum of all negative numbers in the array.
// getNegativeSum(l: [-1, 2, -4, 5, 6]) == -21
// getNegativeSum(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -14
func getNegativeSum(l

func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 44
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the product of all positive numbers in the array.
// productPositive(l: [-1, 2, -4, 5, 6]) == -1
// productPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

func getPositive(l: [Int]) -> [Int] {
    return l.filter { $0 > 0 }
}

func getSum(l: [Int]) -> Int {
    return l.reduce(0, +)
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    return l.filter { $0 > 0 }
}

// Return the sum of all numbers in the array.
// getSum(l: [-1, 2, -4, 5, 6]) == 13
// getSum(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 143
func getSum(l: [Int]) -> Int {
    return l.reduce(0, +)
}

// Return the product of all numbers in the array.
// getProduct(l: [-1, 2, -4, 5, 6]) == -4
// getProduct(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -49500000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

func getPositiveSquaresSum(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i * i
        }
    }
    return result
}

func getPositiveSquaresSumExcludingThree(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 {
            result += i * i
        }
    }
    return result
}

func getPositiveSquaresSumExcludingThreeAndTen(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 {
            result += i * i
        }
    }
    return result
}

func getPositiveSquaresSumExcludingThreeAndTenAndFive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 && i % 5!= 0 {
            result += i * i
        }
    }
    return result
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array.
// getPositiveSquaresSum(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSum(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 210
func getPositiveSquaresSum(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i * i
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array,
// but exclude any number divisible by 3.
// getPositiveSquaresSumExcludingThree(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSumExcludingThree(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 213
func getPositiveSquaresSumExcludingThree(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 {
            result += i * i
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array,
// but exclude any number divisible by 3 and any number greater than 10.
// getPositiveSquaresSumExcludingThreeAndTen(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSumExcludingThreeAndTen(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 210
func getPositiveSquaresSumExcludingThreeAndTen(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 {
            result += i * i
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array,
// but exclude any number divisible by 3, any number greater than 10,
// and any number that is a multiple of 5.
// getPositiveSquaresSumExcludingThreeAndTenAndFive(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSumExcludingThreeAndTenAndFive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 213
func getPositiveSquaresSumExcludingThreeAndTenAndFive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 && i % 5!= 0 {
            result += i * i
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array,
// but exclude any number divisible by 3, any number greater than 10,
// any number that is a multiple of 5, and any number that is a multiple of 7.
// getPositiveSquaresSumExcludingThreeAndTenAndFiveAndSeven(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSumExcludingThreeAndTenAndFiveAndSeven(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 210
func getPositiveSquaresSumExcludingThreeAndTenAndFiveAndSeven(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 && i % 5!= 0 && i % 7

func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 45
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 45
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 45
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 45
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 45
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 45
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 45
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3

func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

func countPositive(l: [Int]) -> (Int, Int) {
    var result = 0
    var count = 0
    for i in l {
        if i > 0 {
            result += i
            count += 1
        }
    }
    return (result, count)
}

func countPositiveTuple(l: [Int]) -> (Int, Int) {
    var result = 0
    var count = 0
    for i in l {
        if i > 0 {
            result += i
            count += 1
        }
    }
    return (result, count)
}

func countPositiveTuple2(l: [Int]) -> (Int, Int) {
    var result = 0
    var count = 0
    for i in l {
        if i > 0 {
            result += i
            count += 1
        }
    }
    return (result, count)
}

func countPositiveTuple3(l: [Int]) -> (Int, Int) {
    var result = 0
    var count = 0
    for i in l {
        if i > 0 {
            result += i
            count += 1
        }
    }
    return (result, count)
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 44
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all positive numbers in the array,
// but also count the number of positive numbers.
// countPositive(l: [-1, 2, -4, 5, 6]) == (11, 3)
// countPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (44, 11)
func countPositive(l: [Int]) -> (Int, Int) {
    var result = 0
    var count = 0
    for i in l {
        if i > 0 {
            result += i
            count += 1
        }
    }
    return (result, count)
}

// Return the sum of all positive numbers in the array,
// but also count the number of positive numbers.
// The function should return a tuple containing the sum and the count.
// countPositiveTuple(l: [-1, 2, -4, 5, 6]) == (11, 3)
// countPositiveTuple(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (44, 11)
func countPositiveTuple(l: [Int]) -> (Int, Int) {
    var result = 0
    var count = 0
    for i in l {
        if i > 0 {
            result += i
            count += 1
        }
    }
    return (result, count)
}

// Return the sum of all positive numbers in the array,
// but also count the number of positive numbers.
// The function should return a tuple containing the sum and the count.
// countPositiveTuple(l: [-1, 2, -4, 5, 6]) == (11, 3)
// countPositiveTuple(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (44, 11)
func countPositiveTuple2(l: [Int]) -> (Int, Int) {
    var result = 0
    var count = 0
    for i in l {
        if i > 0 {
            result += i
            count += 1
        }
    }
    return (result, count)
}

// Return the sum of all positive numbers in the array,
// but also count the number of positive numbers.
// The function should return a tuple containing the sum and the count.
// countPositiveTuple(l: [-1, 2, -4, 5, 6]) == (11, 3)
// countPositiveTuple(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (44, 11)
func countPositiveTuple3(l: [Int]) -> (Int, Int) {
    var result = 0
    var count = 0
    for i in l {
        if i > 0 {
            result += i
            count += 1
        }
    }
    return (result, count)
}

// Return the sum of all positive numbers in the array,
// but also count the number of positive numbers.
// The function should return a tuple containing the sum and the count.
// countPositiveTuple(l: [-1, 2, -4, 5, 6]) == (11, 3)
// countPositiveTuple(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) ==

func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

func getPositiveSquaresSum(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i * i
        }
    }
    return result
}

func getPositiveSquaresSumExceptThree(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 {
            result += i * i
        }
    }
    return result
}

func getPositiveSquaresSumExceptThreeAndTen(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 {
            result += i * i
        }
    }
    return result
}

func getPositiveSquaresSumExceptThreeAndTenAndFive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 && i % 5!= 0 {
            result += i * i
        }
    }
    return result
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array.
// getPositiveSquaresSum(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSum(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 156
func getPositiveSquaresSum(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i * i
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array,
// but exclude any number divisible by 3.
// getPositiveSquaresSumExceptThree(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSumExceptThree(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 161
func getPositiveSquaresSumExceptThree(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 {
            result += i * i
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array,
// but exclude any number divisible by 3 and any number greater than 10.
// getPositiveSquaresSumExceptThreeAndTen(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSumExceptThreeAndTen(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 156
func getPositiveSquaresSumExceptThreeAndTen(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 {
            result += i * i
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array,
// but exclude any number divisible by 3, any number greater than 10,
// and any number that is a multiple of 5.
// getPositiveSquaresSumExceptThreeAndTenAndFive(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSumExceptThreeAndTenAndFive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 151
func getPositiveSquaresSumExceptThreeAndTenAndFive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 && i % 5!= 0 {
            result += i * i
        }
    }
    return result
}

// Return the sum of the squares of the positive numbers in the array,
// but exclude any number divisible by 3, any number greater than 10,
// any number that is a multiple of 5, and any number that is a multiple of 7.
// getPositiveSquaresSumExceptThreeAndTenAndFiveAndSeven(l: [-1, 2, -4, 5, 6]) == 56
// getPositiveSquaresSumExceptThreeAndTenAndFiveAndSeven(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 141
func getPositiveSquaresSumExceptThreeAndTenAndFiveAndSeven(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 && i % 3!= 0 && i <= 10 && i % 5!= 0 && i % 7

func getPositive(l: [Int]) -> [Int] {
    var positive = [Int]()
    for i in l {
        if i > 0 {
            positive.append(i)
        }
    }
    return positive
}

func sum(l: [Int]) -> Int {
    var sum = 0
    for i in l {
        sum += i
    }
    return sum
}

func average(l: [Int]) -> Double {
    return Double(sum(l: l)) / Double(l.count)
}

func median(l: [Int]) -> Int {
    var sorted = l
    sorted.sort()
    if sorted.count % 2 == 0 {
        return (sorted[sorted.count / 2 - 1] + sorted[sorted.count / 2]) / 2
    } else {
        return sorted[sorted.count / 2]
    }
}

func mode(l: [Int]) -> Int {
    var counts = [Int: Int]()
    for i in l {
        counts[i, default: 0] += 1
    }
    var maxCount = 0
    var mode = 0
    for (num, count) in counts {
        if count > maxCount {
            maxCount = count
            mode = num
        }
    }
    return mode
}

func range(l: [Int]) -> Int {
    var sorted = l
    sorted.sort()
    return sorted[sorted.count - 1] - sorted[0]
}

func standardDeviation(l: [Int]) -> Double {
    var mean = average(l: l)
    var sum = 0.0
    for i in l {
        sum += (Double(i) - mean) * (Double(i) - mean)
    }
    return sqrt(sum / Double(l.count - 1))
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    var positive = [Int]()
    for i in l {
        if i > 0 {
            positive.append(i)
        }
    }
    return positive
}

// Return the sum of all numbers in the array.
// sum(l: [-1, 2, -4, 5, 6]) == 15
// sum(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 15
func sum(l: [Int]) -> Int {
    var sum = 0
    for i in l {
        sum += i
    }
    return sum
}

// Return the average of all numbers in the array.
// average(l: [-1, 2, -4, 5, 6]) == 0.75
// average(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 15.714285714285714
func average(l: [Int]) -> Double {
    return Double(sum(l: l)) / Double(l.count)
}

// Return the median of all numbers in the array.
// median(l: [-1, 2, -4, 5, 6]) == 3
// median(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 3
func median(l: [Int]) -> Int {
    var sorted = l
    sorted.sort()
    if sorted.count % 2 == 0 {
        return (sorted[sorted.count / 2 - 1] + sorted[sorted.count / 2]) / 2
    } else {
        return sorted[sorted.count / 2]
    }
}

// Return the mode of all numbers in the array.
// mode(l: [-1, 2, -4, 5, 6, 5, 2, 2, 2, 2]) == 2
// mode(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10, 1, 1, 1, 1, 1]) == 1
func mode(l: [Int]) -> Int {
    var counts = [Int: Int]()
    for i in l {
        counts[i, default: 0] += 1
    }
    var maxCount = 0
    var mode = 0
    for (num, count) in counts {
        if count > maxCount {
            maxCount = count
            mode = num
        }
    }
    return mode
}

// Return the range of all numbers in the array.
// range(l: [-1, 2, -4, 5, 6]) == 7
// range(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 124
func range(l: [Int]) -> Int {
    var sorted = l
    sorted.sort()
    return sorted[sorted.count - 1] - sorted[0]
}

// Return the standard deviation of all numbers in the array.
// standardDeviation(l: [-1, 2, -4, 5, 6]) == 2.5
// standardDeviation(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 289.7960754557402
func standardDeviation(l: [Int]) -> Double {
    var mean = average(l: l)
    var sum = 0.0
    for i in l {
        sum += (Double(i) - mean) * (Double(i) - mean)
    }
    return sqrt(sum / Double(l.count - 1))
}

// Return the number of positive numbers in the array.
// countPositive(l: [-1, 2, -4, 5, 6]) == 3
// countPositive(l: [5, 3, -5, 2, -3, 3, 

func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

func sumNegative(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i < 0 {
            result += i
        }
    }
    return result
}

func sumAll(l: [Int]) -> Int {
    var result = 0
    for i in l {
        result += i
    }
    return result
}

func avgAll(l: [Int]) -> Double {
    var result = 0
    for i in l {
        result += i
    }
    return Double(result) / Double(l.count)
}

func countPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += 1
        }
    }
    return result
}

func countNegative(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i < 0 {
            result += 1
        }
    }
    return result
}

func countZeros(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i == 0 {
            result += 1
        }
    }
    return result
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if i > 0 {
            result.append(i)
        }
    }
    return result
}

// Return the sum of all positive numbers in the array.
// sumPositive(l: [-1, 2, -4, 5, 6]) == 11
// sumPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 39
func sumPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all negative numbers in the array.
// sumNegative(l: [-1, 2, -4, 5, 6]) == -11
// sumNegative(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -45
func sumNegative(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i < 0 {
            result += i
        }
    }
    return result
}

// Return the sum of all numbers in the array.
// sumAll(l: [-1, 2, -4, 5, 6]) == -1
// sumAll(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 128
func sumAll(l: [Int]) -> Int {
    var result = 0
    for i in l {
        result += i
    }
    return result
}

// Return the average of all numbers in the array.
// avgAll(l: [-1, 2, -4, 5, 6]) == -0.3333333333333333
// avgAll(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 14.285714285714285
func avgAll(l: [Int]) -> Double {
    var result = 0
    for i in l {
        result += i
    }
    return Double(result) / Double(l.count)
}

// Return the number of positive numbers in the array.
// countPositive(l: [-1, 2, -4, 5, 6]) == 3
// countPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 11
func countPositive(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i > 0 {
            result += 1
        }
    }
    return result
}

// Return the number of negative numbers in the array.
// countNegative(l: [-1, 2, -4, 5, 6]) == 4
// countNegative(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 11
func countNegative(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i < 0 {
            result += 1
        }
    }
    return result
}

// Return the number of zeros in the array.
// countZeros(l: [-1, 2, -4, 0, 5, 6]) == 1
// countZeros(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 4
func countZeros(l: [Int]) -> Int {
    var result = 0
    for i in l {
        if i == 0 {
            result += 1
        }
    }
    return result
}

// Return the number of odd numbers in the array.
// countOdd(l: [-1, 2, -4, 5, 6]) == 2
//

func getPositive(l: [Int]) -> [Int] {
    return l.filter { $0 > 0 }
}

func getSum(l: [Int]) -> Int {
    return l.reduce(0, +)
}

func getAverage(l: [Int]) -> Double {
    return Double(getSum(l: l)) / Double(l.count)
}

func getMedian(l: [Int]) -> Int {
    let sorted = l.sorted()
    let mid = sorted.count / 2
    return sorted[mid]
}

func getMode(l: [Int]) -> [Int] {
    var counts = [Int: Int]()
    for num in l {
        counts[num, default: 0] += 1
    }
    return counts.max { $0.value < $1.value }!.key
}

func getRange(l: [Int]) -> Int {
    return l.max()! - l.min()!
}

func getStandardDeviation(l: [Int]) -> Double {
    let avg = getAverage(l: l)
    let sum = l.reduce(0) { $0 + ($1 - avg) * ($1 - avg) }
    return sqrt(sum / Double(l.count - 1))
}

```swift
// Return only positive numbers in the array.
// getPositive(l: [-1, 2, -4, 5, 6]) == [2, 5, 6]
// getPositive(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [5, 3, 2, 3, 9, 123, 1]
func getPositive(l: [Int]) -> [Int] {
    return l.filter { $0 > 0 }
}

// Return the sum of all numbers in the array.
// getSum(l: [-1, 2, -4, 5, 6]) == 13
// getSum(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 147
func getSum(l: [Int]) -> Int {
    return l.reduce(0, +)
}

// Return the average of all numbers in the array.
// getAverage(l: [-1, 2, -4, 5, 6]) == 1.875
// getAverage(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 115.4375
func getAverage(l: [Int]) -> Double {
    return Double(getSum(l: l)) / Double(l.count)
}

// Return the median of all numbers in the array.
// getMedian(l: [-1, 2, -4, 5, 6]) == 3
// getMedian(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 3
func getMedian(l: [Int]) -> Int {
    let sorted = l.sorted()
    let mid = sorted.count / 2
    return sorted[mid]
}

// Return the mode of all numbers in the array.
// getMode(l: [-1, 2, -4, 5, 6, 5, 2, 2, 2]) == [2]
// getMode(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10, 1, 1, 1, 1]) == [1]
func getMode(l: [Int]) -> [Int] {
    var counts = [Int: Int]()
    for num in l {
        counts[num, default: 0] += 1
    }
    return counts.max { $0.value < $1.value }!.key
}

// Return the range of all numbers in the array.
// getRange(l: [-1, 2, -4, 5, 6]) == 7
// getRange(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 124
func getRange(l: [Int]) -> Int {
    return l.max()! - l.min()!
}

// Return the standard deviation of all numbers in the array.
// getStandardDeviation(l: [-1, 2, -4, 5, 6]) == 2.5
// getStandardDeviation(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 289.83684210526316
func getStandardDeviation(l: [Int]) -> Double {
    let avg = getAverage(l: l)
    let sum = l.reduce(0) { $0 + ($1 - avg) * ($1 - avg) }
    return sqrt(sum / Double(l.count - 1))
}

// Return the frequency of each unique pair of numbers in the array.
// getPairFrequency(l: [-1, 2, -4, 5, 6]) == [(-1, 1), (2, 1), (-4, 1), (5, 1), (6, 1)]
// getPairFrequency(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == [(-10, 1), (0, 1), (1, 1), (123, 1), (2, 2), (3, 2), (-5, 2), (-3, 2), (5, 2), (6,

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func prime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingThreeAndSeven(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 3!= 0 && i % 7!= 0 {
            sum += i
        }
    }
    return sum
}

func printPrimes(n: Int) {
    for i in 1...n {
        print(prime(n: i))
    }
}

func printPrimesExcludingThreeAndSeven(n: Int) {
    for i in 1...n {
        if i % 3!= 0 && i % 7!= 0 {
            print(prime(n: i))
        }
    }
}

func printSumOfPrimes(n: Int) {
    print(sumOfPrimes(n: n))
}

func printSumOfPrimesExcludingThreeAndSeven(n: Int) {
    print(sumOfPrimesExcludingThreeAndSeven(n: n))
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the nth prime number.
// prime(n: 1) == 2
// prime(n: 2) == 3
// prime(n: 6) == 13
// prime(n: 10) == 29
func prime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

// Return the sum of all prime numbers between 1 and n.
// sumOfPrimes(n: 10) == 17
// sumOfPrimes(n: 20) == 77
func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers that are divisible by both 3 and 7.
// sumOfPrimesExcludingThreeAndSeven(n: 100) == 501
// sumOfPrimesExcludingThreeAndSeven(n: 1000) == 233168
func sumOfPrimesExcludingThreeAndSeven(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 3!= 0 && i % 7!= 0 {
            sum += i
        }
    }
    return sum
}

// Print the first n prime numbers.
// printPrimes(n: 5)
// 2
// 3
// 5
// 7
// 11
func printPrimes(n: Int) {
    for i in 1...n {
        print(prime(n: i))
    }
}

// Print the first n prime numbers, excluding the numbers that are divisible by both 3 and 7.
// printPrimesExcludingThreeAndSeven(n: 5)
// 2
// 3
// 5
// 11
// 13
func printPrimesExcludingThreeAndSeven(n: Int) {
    for i in 1...n {
        if i % 3!= 0 && i % 7!= 0 {
            print(prime(n: i))
        }
    }
}

// Print the sum of all prime numbers between 1 and n.
// printSumOfPrimes(n: 10)
// 17
// printSumOfPrimes(n: 20)
// 77
func printSumOfPrimes(n: Int) {
    print(sumOfPrimes(n: n))
}

// Print the sum of all prime numbers between 1 and n, excluding the numbers that are divisible by both 3 and 7.
// printSumOfPrimesExcludingThreeAndSeven(n: 100)
// 501
// printSumOfPrimesExcludingThreeAndSeven(n: 1000)
// 233168
func printSumOfPrimesExcludingThreeAndSeven(n: Int) {
    print(sumOfPrimesExcludingThreeAndSeven(n: n))
}

// Calculate the sum of all prime numbers between 1 and 1,000,000,000,000,000,000,000.
// sumOfPrimes(n: 10000000000000000000)
// 7476196110822839660
func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Calculate the sum of all prime numbers between 1 and 1,000,000,000,000,00

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func sumOfPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

func sumOfEvenPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

func sumOfOddPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2!= 0 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingThrees(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 3!= 0 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingThreesAndFives(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 3!= 0 && i % 5!= 0 {
            sum += i
        }
    }
    return sum
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the sum of all prime numbers between 1 and a given number.
// sumOfPrimes(upTo: 10) == 17
// sumOfPrimes(upTo: 20) == 77
// sumOfPrimes(upTo: 100) == 2297
// sumOfPrimes(upTo: 1000) == 23279
func sumOfPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all even prime numbers between 1 and a given number.
// sumOfEvenPrimes(upTo: 10) == 2
// sumOfEvenPrimes(upTo: 20) == 10
// sumOfEvenPrimes(upTo: 100) == 66
// sumOfEvenPrimes(upTo: 1000) == 364
func sumOfEvenPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all odd prime numbers between 1 and a given number.
// sumOfOddPrimes(upTo: 10) == 1
// sumOfOddPrimes(upTo: 20) == 19
// sumOfOddPrimes(upTo: 100) == 53
// sumOfOddPrimes(upTo: 1000) == 332
func sumOfOddPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2!= 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and a given number,
// excluding any prime numbers that are divisible by 3.
// sumOfPrimesExcludingThrees(upTo: 10) == 1
// sumOfPrimesExcludingThrees(upTo: 20) == 7
// sumOfPrimesExcludingThrees(upTo: 100) == 231
// sumOfPrimesExcludingThrees(upTo: 1000) == 2516
func sumOfPrimesExcludingThrees(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 3!= 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and a given number,
// excluding any prime numbers that are divisible by 3 or 5.
// sumOfPrimesExcludingThreesAndFives(upTo: 10) == 1
// sumOfPrimesExcludingThreesAndFives(upTo: 20) == 7
// sumOfPrimesExcludingThreesAndFives(upTo: 100) == 221
// sumOfPrimesExcludingThreesAndFives(upTo: 1000) == 2231
func sumOfPrimesExcludingThreesAndFives(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 3!= 0 && i % 5!= 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and a given number,
// excluding any prime numbers that are divisible by 2, 3, or 5.
// sumOfPrimesExcludingTwosThreesFives(upTo: 10) == 1
// sumOfPrimesExcludingTwosThreesFives

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func prime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

func sumOfEvenPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

func sumOfOddPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 1 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 && i!= 13 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 && i!= 13 && i!= 17 {
            sum += i
        }
    }
    return sum
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the nth prime number.
// prime(n: 1) == 2
// prime(n: 2) == 3
// prime(n: 6) == 13
// prime(n: 10) == 29
func prime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

// Return the sum of all prime numbers between 1 and n.
// sumOfPrimes(n: 10) == 17
// sumOfPrimes(n: 20) == 77
func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all even prime numbers between 1 and n.
// sumOfEvenPrimes(n: 10) == 18
// sumOfEvenPrimes(n: 20) == 88
func sumOfEvenPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all odd prime numbers between 1 and n.
// sumOfOddPrimes(n: 10) == 17
// sumOfOddPrimes(n: 20) == 87
func sumOfOddPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 1 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 5, 7, and 11.
// sumOfPrimesExcluding(n: 10) == 16
// sumOfPrimesExcluding(n: 20) == 72
func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 5, 7, 11, and 13.
// sumOfPrimesExcluding(n: 10) == 16
// sumOfPrimesExcluding(n: 20) == 72
func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 && i!= 13 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 5, 7, 11, 13, and 17.
// sumOfPrimesExcluding(n: 10) == 16
// sumOfPrimesExcluding(n: 20) == 72
func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 && i!= 13 && i!= 17 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 5, 7, 11, 13, 17, and 19.
// sumOfPrimesExcluding(n: 10) == 16
// sumOfPrimesExcluding(n: 20) == 

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func prime(n: Int) -> Int {
    var primes = [2, 3]
    var i = 1
    while primes.count < n {
        i += 1
        if isPrime(n: i) {
            primes.append(i)
        }
    }
    return primes[n - 1]
}

func fibonacci(n: Int) -> Int {
    var fibs = [1, 1]
    var i = 1
    while fibs.count < n {
        i += 1
        fibs.append(fibs[i - 2] + fibs[i - 1])
    }
    return fibs[n - 1]
}

func fibonacciValue(n: Int) -> Int {
    if n <= 2 {
        return 1
    }
    return fibonacciValue(n: n - 1) + fibonacciValue(n: n - 2)
}

func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

func sumOfFibonacci(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        sum += fibonacci(n: i)
    }
    return sum
}

func sumOfPrimeFibonacci(n: Int) -> Int {
    return sumOfPrimes(n: n) + sumOfFibonacci(n: n)
}

func digitalSum(n: Int) -> Int {
    if n <= 2 {
        return 1
    }
    return digitalSum(n: n - 1) + digitalSumValue(n: n - 1)
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the nth prime number.
// prime(n: 1) == 2
// prime(n: 2) == 3
// prime(n: 6) == 13
// prime(n: 10) == 29
func prime(n: Int) -> Int {
    var primes = [2, 3]
    var i = 1
    while primes.count < n {
        i += 1
        if isPrime(n: i) {
            primes.append(i)
        }
    }
    return primes[n - 1]
}

// Return the nth Fibonacci number.
// fibonacci(n: 1) == 1
// fibonacci(n: 2) == 1
// fibonacci(n: 6) == 8
// fibonacci(n: 10) == 55
func fibonacci(n: Int) -> Int {
    var fibs = [1, 1]
    var i = 1
    while fibs.count < n {
        i += 1
        fibs.append(fibs[i - 2] + fibs[i - 1])
    }
    return fibs[n - 1]
}

// Return the nth value of the Fibonacci sequence.
// fibonacciValue(n: 1) == 1
// fibonacciValue(n: 2) == 1
// fibonacciValue(n: 6) == 8
// fibonacciValue(n: 10) == 55
func fibonacciValue(n: Int) -> Int {
    if n <= 2 {
        return 1
    }
    return fibonacciValue(n: n - 1) + fibonacciValue(n: n - 2)
}

// Return the sum of all prime numbers between 1 and n.
// sumOfPrimes(n: 10) == 17
// sumOfPrimes(n: 20) == 77
// sumOfPrimes(n: 100) == 2233706237
func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all Fibonacci numbers between 1 and n.
// sumOfFibonacci(n: 10) == 143
// sumOfFibonacci(n: 20) == 660
// sumOfFibonacci(n: 100) == 354224848179261908320
func sumOfFibonacci(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        sum += fibonacci(n: i)
    }
    return sum
}

// Return the sum of all prime and Fibonacci numbers between 1 and n.
// sumOfPrimeFibonacci(n: 10) == 17
// sumOfPrimeFibonacci(n: 20) == 109
// sumOfPrimeFibonacci(n: 100) == 4455071317
func sumOfPrimeFibonacci(n: Int) -> Int {
    return sumOfPrimes(n: n) + sumOfFibonacci(n: n)
}

// Return the nth value of the digital sum sequence.
// digitalSum(n: 1) == 1
// digitalSum(n: 2) == 1
// digitalSum(n: 6) == 9
// digitalSum(n: 10) == 19
func digitalSum(n: Int) -> Int {
    if n <= 2 {
        return 1
    }
    return digitalSum(n: n - 1) + digitalSumValue(n: n - 1)
}

// Return the nth value

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func prime(n: Int) -> Int {
    var primes: [Int] = [2, 3]
    var i = 1
    while primes.count < n {
        i += 1
        if isPrime(n: i) {
            primes.append(i)
        }
    }
    return primes[n - 1]
}

func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingThreeAndSeven(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if isPrime(n: i) && i % 3!= 0 && i % 7!= 0 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingThreeAndSevenOptimized(n: Int) -> Int {
    var sum = 0
    var primes = [Bool](repeating: true, count: n + 1)
    primes[0] = false
    primes[1] = false
    for i in 2...Int(sqrt(Double(n))) {
        if primes[i] {
            for j in stride(from: i * i, to: n + 1, by: i) {
                primes[j] = false
            }
        }
    }
    for i in 2...n {
        if primes[i] && i % 3!= 0 && i % 7!= 0 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingThreeAndSevenOptimizedIsPrime(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if isPrime(n: i) && i % 3!= 0 && i % 7!= 0 {
            sum += i
        }
    }
    return sum
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the nth prime number.
// prime(n: 1) == 2
// prime(n: 2) == 3
// prime(n: 6) == 13
// prime(n: 10) == 29
func prime(n: Int) -> Int {
    var primes: [Int] = [2, 3]
    var i = 1
    while primes.count < n {
        i += 1
        if isPrime(n: i) {
            primes.append(i)
        }
    }
    return primes[n - 1]
}

// Return the sum of all prime numbers between 1 and n.
// sumOfPrimes(n: 10) == 17
// sumOfPrimes(n: 20) == 77
func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding any prime numbers that are divisible by both 3 and 7.
// sumOfPrimesExcludingThreeAndSeven(n: 100) == 500
// sumOfPrimesExcludingThreeAndSeven(n: 1000) == 2297
func sumOfPrimesExcludingThreeAndSeven(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if isPrime(n: i) && i % 3!= 0 && i % 7!= 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding any prime numbers that are divisible by both 3 and 7,
// and calculating the sum using the optimized Sieve of Eratosthenes algorithm.
// sumOfPrimesExcludingThreeAndSeven(n: 100) == 500
// sumOfPrimesExcludingThreeAndSeven(n: 1000) == 2297
func sumOfPrimesExcludingThreeAndSevenOptimized(n: Int) -> Int {
    var sum = 0
    var primes = [Bool](repeating: true, count: n + 1)
    primes[0] = false
    primes[1] = false
    for i in 2...Int(sqrt(Double(n))) {
        if primes[i] {
            for j in stride(from: i * i, to: n + 1, by: i) {
                primes[j] = false
            }
        }
    }
    for i in 2...n {
        if primes[i] && i % 3!= 0 && i % 7!= 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding any prime numbers that are divisible by both 3 and 7,
// and calculating the sum using the optimized Sieve of Eratosthenes algorithm and the isPrime function.
// sumOfPrimesExcludingThreeAndSeven(n: 100) == 500
// sumOfPrimesExcludingThreeAndSeven(n: 1000) == 2297
func sumOfPrimesExcludingThreeAndSevenOptimizedIsPrime(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if isPrime(n: i) && i % 3!= 0 && i % 7!= 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding any prime numbers that are divisible by both 3 and 7,
// and calculating the sum using the optimized Sieve of Eratosthenes algorithm and the prime function.
// sumOfPrimesExcludingThreeAndSeven(n: 100) == 500
// sumOfPrimesExcludingThreeAndSeven(n: 1000)

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func prime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingDivisibleBy(n: Int, d: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % d!= 0 {
            sum += i
        }
    }
    return sum
}

func fibonacci(n: Int) -> Int {
    if n <= 2 {
        return 1
    }
    var a = 1
    var b = 1
    for _ in 3...n {
        let c = a + b
        a = b
        b = c
    }
    return b
}

func sumOfFibonacci(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        sum += fibonacci(n: i)
    }
    return sum
}

func sumOfFibonacciExcludingDivisibleBy(n: Int, d: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if i % d!= 0 {
            sum += fibonacci(n: i)
        }
    }
    return sum
}

func triangular(n: Int) -> Int {
    return n * (n + 1) / 2
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the nth prime number.
// prime(n: 1) == 2
// prime(n: 2) == 3
// prime(n: 6) == 13
// prime(n: 10) == 29
func prime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

// Return the sum of all prime numbers between 1 and n.
// sumOfPrimes(n: 10) == 17
// sumOfPrimes(n: 20) == 77
func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding those that are divisible by a given prime number d.
// sumOfPrimesExcludingDivisibleBy(n: 10, d: 3) == 19
// sumOfPrimesExcludingDivisibleBy(n: 20, d: 7) == 151
func sumOfPrimesExcludingDivisibleBy(n: Int, d: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % d!= 0 {
            sum += i
        }
    }
    return sum
}

// Return the nth Fibonacci number.
// fibonacci(n: 1) == 1
// fibonacci(n: 2) == 1
// fibonacci(n: 6) == 8
// fibonacci(n: 10) == 55
func fibonacci(n: Int) -> Int {
    if n <= 2 {
        return 1
    }
    var a = 1
    var b = 1
    for _ in 3...n {
        let c = a + b
        a = b
        b = c
    }
    return b
}

// Return the sum of all Fibonacci numbers between 1 and n.
// sumOfFibonacci(n: 10) == 143
// sumOfFibonacci(n: 20) == 660
func sumOfFibonacci(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        sum += fibonacci(n: i)
    }
    return sum
}

// Return the sum of all Fibonacci numbers between 1 and n, excluding those that are divisible by a given prime number d.
// sumOfFibonacciExcludingDivisibleBy(n: 10, d: 3) == 14
// sumOfFibonacciExcludingDivisibleBy(n: 20, d: 7) == 103
func sumOfFibonacciExcludingDivisibleBy(n: Int, d: Int) -> Int {
    var sum = 0
    for i in 1...n {
        if i % d!= 0 {
            sum += fibonacci(n: i)
        }
    }
    return sum
}

// Return the nth triangular number.
// triangular(n: 1) == 1
// triangular(n: 2) == 3
// triangular(n: 6) == 21
// triangular(n: 10) == 75
func triangular(n: Int) -> Int {
    return n * (n + 1) / 2
}

// Return the sum of all triangular numbers between 1 and n.
// sumOfTriangular(n: 10) == 55
// sumOfTriangular(n: 20) == 335
func sumOfTriangular(n: Int) -> Int {
    var sum = 0
    for i in 1...n {
        sum +=

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func getNthPrime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

func sumPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

func arraySquare(_ array: [Int]) -> [Int] {
    var newArray = [Int]()
    for i in array {
        newArray.append(i * i)
    }
    return newArray
}

func arraySquareReverse(_ array: [Int]) -> [Int] {
    var newArray = [Int]()
    for i in array.reversed() {
        newArray.append(i * i)
    }
    return newArray
}

func arrayDiff(_ array: [Int]) -> Int {
    return array.max()! - array.min()!
}

func arrayDiffPos(_ array: [Int]) -> Int {
    var newArray = [Int]()
    for i in array {
        if i > 0 {
            newArray.append(i)
        }
    }
    return newArray.max()! - newArray.min()!
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2..<n {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the nth prime number.
// getNthPrime(n: 1) == 2
// getNthPrime(n: 2) == 3
// getNthPrime(n: 3) == 5
// getNthPrime(n: 4) == 7
// getNthPrime(n: 5) == 11
// getNthPrime(n: 6) == 13
// getNthPrime(n: 10) == 29
func getNthPrime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

// Return the sum of all prime numbers between 1 and n.
// sumPrimes(n: 10) == 17
// sumPrimes(n: 100) == 1277
// sumPrimes(n: 1000) == 22377
func sumPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Given an array of integers, return a new array containing the squares of the values, in the same order.
// Example:
// arraySquare([1, 2, 3]) == [1, 4, 9]
// arraySquare([4, 8, 12, 16]) == [16, 64, 441, 324]
func arraySquare(_ array: [Int]) -> [Int] {
    var newArray = [Int]()
    for i in array {
        newArray.append(i * i)
    }
    return newArray
}

// Given an array of integers, return a new array containing the squares of the values, in reverse order.
// Example:
// arraySquareReverse([1, 2, 3]) == [9, 4, 1]
// arraySquareReverse([4, 8, 12, 16]) == [324, 64, 441, 16]
func arraySquareReverse(_ array: [Int]) -> [Int] {
    var newArray = [Int]()
    for i in array.reversed() {
        newArray.append(i * i)
    }
    return newArray
}

// Given an array of integers, return the difference between the largest and smallest values.
// Example:
// arrayDiff([1, 2, 3]) == 2
// arrayDiff([4, 8, 12, 16]) == 16
func arrayDiff(_ array: [Int]) -> Int {
    return array.max()! - array.min()!
}

// Given an array of integers, return the difference between the largest and smallest values,
// excluding negative numbers.
// Example:
// arrayDiffPos([1, 2, 3]) == 2
// arrayDiffPos([4, 8, 12, 16]) == 12
func arrayDiffPos(_ array: [Int]) -> Int {
    var newArray = [Int]()
    for i in array {
        if i > 0 {
            newArray.append(i)
        }
    }
    return newArray.max()! - newArray.min()!
}

// Given an array of integers, return the number of values that are greater than the previous value.
// First value is always 1.
// Example:
// arrayPeak([1, 2, 3]) == [1, 2, 1]
// arrayPeak([4, 8, 12, 16]) == [1, 1, 2, 1]
func arrayPeak(_ array: [Int]) -> [Int] {
    var newArray = [Int]()
    newArray.append(1)
    for i in 1..<array.count {
        if array[i] > array[i - 1] {
            newArray.append(1)
        } else {
            newArray.append(0)
        }

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func sumOfPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2!= 0 {
            sum += i
        }
    }
    return sum
}

func sumOfEvenPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

func sumOfOddPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2!= 0 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesIncludingEven(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the sum of all prime numbers between 1 and a given number,
// excluding any even prime numbers.
// sumOfPrimes(upTo: 10) == 17
// sumOfPrimes(upTo: 20) == 77
// sumOfPrimes(upTo: 100) == 1260
// sumOfPrimes(upTo: 1000) == 22310
func sumOfPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2!= 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all even prime numbers between 1 and a given number,
// excluding any even prime numbers.
// sumOfEvenPrimes(upTo: 10) == 2
// sumOfEvenPrimes(upTo: 20) == 10
// sumOfEvenPrimes(upTo: 100) == 200
// sumOfEvenPrimes(upTo: 1000) == 3276
func sumOfEvenPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all odd prime numbers between 1 and a given number,
// excluding any even prime numbers.
// sumOfOddPrimes(upTo: 10) == 1
// sumOfOddPrimes(upTo: 20) == 17
// sumOfOddPrimes(upTo: 100) == 251
// sumOfOddPrimes(upTo: 1000) == 4231
func sumOfOddPrimes(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2!= 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and a given number,
// including any even prime numbers.
// sumOfPrimesIncludingEven(upTo: 10) == 18
// sumOfPrimesIncludingEven(upTo: 20) == 88
// sumOfPrimesIncludingEven(upTo: 100) == 1560
// sumOfPrimesIncludingEven(upTo: 1000) == 31340
func sumOfPrimesIncludingEven(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and a given number,
// including any even prime numbers.
// sumOfPrimesIncludingEven(upTo: 10) == 18
// sumOfPrimesIncludingEven(upTo: 20) == 88
// sumOfPrimesIncludingEven(upTo: 100) == 1560
// sumOfPrimesIncludingEven(upTo: 1000) == 31340
func sumOfPrimesIncludingEven(upTo n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and a given number,
// including any even prime numbers.
// sumOfPrimesIncludingEven(upTo: 10) == 18
// sumOfPrimesIncludingEven(upTo: 20) == 88
// sumOfPrimesIncludingEven(upTo: 100) == 1560
// sumOfPrimesIncludingEven(upTo: 1

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func prime(n: Int) -> Int {
    var primes: [Int] = [2, 3]
    var count = 2
    while count < n {
        let next = primes.last! + 2
        if isPrime(n: next) {
            primes.append(next)
            count += 1
        }
    }
    return primes.last!
}

func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

func sumOfEvenPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

func sumOfOddPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 1 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingThreeAndFive(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 3 && i!= 5 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingThreeFiveAndSeven(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 3 && i!= 5 && i!= 7 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcludingThreeFiveSevenAndEleven(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 3 && i!= 5 && i!= 7 && i!= 11 {
            sum += i
        }
    }
    return sum
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the nth prime number.
// prime(n: 1) == 2
// prime(n: 2) == 3
// prime(n: 6) == 13
// prime(n: 10) == 29
func prime(n: Int) -> Int {
    var primes: [Int] = [2, 3]
    var count = 2
    while count < n {
        let next = primes.last! + 2
        if isPrime(n: next) {
            primes.append(next)
            count += 1
        }
    }
    return primes.last!
}

// Return the sum of all prime numbers between 1 and n.
// sumOfPrimes(n: 10) == 17
// sumOfPrimes(n: 20) == 77
func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all even prime numbers between 1 and n.
// sumOfEvenPrimes(n: 10) == 18
// sumOfEvenPrimes(n: 20) == 88
func sumOfEvenPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all odd prime numbers between 1 and n.
// sumOfOddPrimes(n: 10) == 17
// sumOfOddPrimes(n: 20) == 83
func sumOfOddPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 1 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 3 and 5.
// sumOfPrimesExcludingThreeAndFive(n: 10) == 19
// sumOfPrimesExcludingThreeAndFive(n: 20) == 119
func sumOfPrimesExcludingThreeAndFive(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 3 && i!= 5 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 3, 5, and 7.
// sumOfPrimesExcludingThreeFiveAndSeven(n: 10) == 17
// sumOfPrimesExcludingThreeFiveAndSeven(n: 20) == 131
func sumOfPrimesExcludingThreeFiveAndSeven(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 3 && i!= 5 && i!= 7 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 3, 5, 7, and 11.
// sumOfPrimesExcludingThreeFiveSevenAndEleven(n: 10) == 13
// sumOfPrimesExcludingThreeFiveSevenAndEleven(n: 20) == 169
func sumOfPrimesExcludingThreeFiveSevenAndEleven(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 3 && i!= 5 && i!= 7 && i!= 11 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 2, 3,

func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

func prime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

func sumOfEvenPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

func sumOfOddPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 1 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 && i!= 13 {
            sum += i
        }
    }
    return sum
}

func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 && i!= 13 && i!= 17 {
            sum += i
        }
    }
    return sum
}

```swift
// Return true if a given number is prime, and false otherwise.
// isPrime(n: 6) == false
// isPrime(n: 101) == true
// isPrime(n: 11) == true
// isPrime(n: 13441) == true
// isPrime(n: 61) == true
// isPrime(n: 4) == false
// isPrime(n: 1) == false
func isPrime(n: Int) -> Bool {
    if n <= 1 {
        return false
    }
    for i in 2...Int(sqrt(Double(n))) {
        if n % i == 0 {
            return false
        }
    }
    return true
}

// Return the nth prime number.
// prime(n: 1) == 2
// prime(n: 2) == 3
// prime(n: 6) == 13
// prime(n: 10) == 29
func prime(n: Int) -> Int {
    var count = 0
    var num = 2
    while count < n {
        if isPrime(n: num) {
            count += 1
        }
        num += 1
    }
    return num - 1
}

// Return the sum of all prime numbers between 1 and n.
// sumOfPrimes(n: 10) == 17
// sumOfPrimes(n: 20) == 77
func sumOfPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) {
            sum += i
        }
    }
    return sum
}

// Return the sum of all even prime numbers between 1 and n.
// sumOfEvenPrimes(n: 10) == 18
// sumOfEvenPrimes(n: 20) == 88
func sumOfEvenPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 0 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all odd prime numbers between 1 and n.
// sumOfOddPrimes(n: 10) == 17
// sumOfOddPrimes(n: 20) == 83
func sumOfOddPrimes(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i % 2 == 1 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 5, 7, and 11.
// sumOfPrimesExcluding(n: 10) == 16
// sumOfPrimesExcluding(n: 20) == 72
func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 5, 7, 11, and 13.
// sumOfPrimesExcluding(n: 10) == 16
// sumOfPrimesExcluding(n: 20) == 72
func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 && i!= 13 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 5, 7, 11, 13, and 17.
// sumOfPrimesExcluding(n: 10) == 16
// sumOfPrimesExcluding(n: 20) == 72
func sumOfPrimesExcluding(n: Int) -> Int {
    var sum = 0
    for i in 2...n {
        if isPrime(n: i) && i!= 5 && i!= 7 && i!= 11 && i!= 13 && i!= 17 {
            sum += i
        }
    }
    return sum
}

// Return the sum of all prime numbers between 1 and n, excluding the numbers 5, 7, 11, 13, 17, and 19.
// sumOfPrimesExcluding(n: 10) == 16
// sumOfPrimesExcluding(n:

func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l.remove(at: i)
            l.insert(temp, at: i)
        }
        i += 1
    }
    return l
}

func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l.remove(at: i)
            l.insert(temp, at: i)
            i -= 1
        }
        i += 1
    }
    return l
}

func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l.remove(at: i)
            l.insert(temp, at: i)
            i -= 1
        }
        i += 1
    }
    return l
}

func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l.remove(at: i)
            l.insert(temp, at: i)
            i -= 1
        }
        i += 1
    }
    return l
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l.remove(at: i)
            l.insert(temp, at: i)
        }
        i += 1
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l.remove(at: i)
            l.insert(temp, at: i)
            i -= 1
        }
        i += 1
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l.remove(at: i)
            l.insert(temp, at: i)
            i -= 1
        }
        i += 1
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l.remove(at: i)
            l.insert(temp, at: i)
            i -= 1
        }
        i += 1
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird5(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l.remove(at: i)
            l.insert(temp, at: i)
            i -= 1

func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird5(l: [Int]) -> [Int] {
    var l = l
    var i = 0
   

func sortThird(l: [Int]) -> [Int] {
    var l = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1 - i]
            l[l.count - 1 - i] = temp
        }
    }
    return l
}

func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    var j = l.count - 1
    while i < j {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[j]
            l[j] = temp
            j -= 1
        } else {
            i += 1
        }
    }
    return l
}

func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    var j = l.count - 1
    while i < j {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[j]
            l[j] = temp
            j -= 1
        }
        i += 1
    }
    return l
}

func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    var j = l.count - 1
    while i < j {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[j]
            l[j] = temp
            j -= 1
        }
        i += 1
    }
    return l
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1 - i]
            l[l.count - 1 - i] = temp
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    var j = l.count - 1
    while i < j {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[j]
            l[j] = temp
            j -= 1
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    var j = l.count - 1
    while i < j {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[j]
            l[j] = temp
            j -= 1
        }
        i += 1
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    var j = l.count - 1
    while i < j {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[j]
            l[j] = temp
            j -= 1
        }
        i += 1
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird5(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    var j = l.count - 1
    while i < j {
        if l[i] % 3 == 0 {
            let

func sortThird(l: [Int]) -> [Int] {
    var l = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            l[i] = l[i + 1]
            l[i + 1] = l[i]
        }
    }
    return l
}

func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            l[i] = l[i + 1]
            l[i + 1] = l[i]
            i += 1
        }
        i += 1
    }
    return l
}

func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[i + 1]
            l[i + 1] = temp
            i += 1
        }
        i += 1
    }
    return l
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            l[i] = l[i + 1]
            l[i + 1] = l[i]
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            l[i] = l[i + 1]
            l[i + 1] = l[i]
            i += 1
        }
        i += 1
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[i + 1]
            l[i + 1] = temp
            i += 1
        }
        i += 1
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            l[i] = l[i + 1]
            l[i + 1] = l[i]
            i += 1
        }
        i += 1
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[i + 1]
            l[i + 1] = temp
            i += 1
        }
        i += 1
    }
    return

func sortThird(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort()
    return lPrime
}

func sortThird2(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort(by: <)
    return lPrime
}

func sortThird3(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort(by: { $0 < $1 })
    return lPrime
}

func sortThird4(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort(by: { $0 > $1 })
    return lPrime
}

func sortThird5(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort(by: >)
    return lPrime
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort()
    return lPrime
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird2(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort(by: <)
    return lPrime
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird3(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort(by: { $0 < $1 })
    return lPrime
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird4(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort(by: { $0 > $1 })
    return lPrime
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird5(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<l.count {
        if l[i] % 3 == 0 {
            lPrime[i] = l[i + 1]
        }
    }
    lPrime.sort(by: >)
    return lPrime
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies

func sortThird(l: [Int]) -> [Int] {
    var lPrime = l
    var i = 0
    while i < lPrime.count {
        if lPrime[i] % 3 == 0 {
            lPrime[i] = lPrime[i + 1]
            lPrime[i + 1] = lPrime[i]
            i += 2
        } else {
            i += 1
        }
    }
    return lPrime
}

func sortThird2(l: [Int]) -> [Int] {
    var lPrime = l
    var i = 0
    while i < lPrime.count {
        if lPrime[i] % 3 == 0 {
            let temp = lPrime[i]
            lPrime[i] = lPrime[i + 1]
            lPrime[i + 1] = temp
            i += 2
        } else {
            i += 1
        }
    }
    return lPrime
}

func sortThird3(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<lPrime.count {
        if lPrime[i] % 3 == 0 {
            let temp = lPrime[i]
            lPrime[i] = lPrime[i + 1]
            lPrime[i + 1] = temp
        }
    }
    return lPrime
}

func sortThird4(l: [Int]) -> [Int] {
    var lPrime = l
    var i = 0
    while i < lPrime.count {
        if lPrime[i] % 3 == 0 {
            let temp = lPrime[i]
            lPrime[i] = lPrime[i + 1]
            lPrime[i + 1] = temp
            i += 2
        } else {
            i += 1
        }
    }
    return lPrime
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var lPrime = l
    var i = 0
    while i < lPrime.count {
        if lPrime[i] % 3 == 0 {
            lPrime[i] = lPrime[i + 1]
            lPrime[i + 1] = lPrime[i]
            i += 2
        } else {
            i += 1
        }
    }
    return lPrime
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird2(l: [Int]) -> [Int] {
    var lPrime = l
    var i = 0
    while i < lPrime.count {
        if lPrime[i] % 3 == 0 {
            let temp = lPrime[i]
            lPrime[i] = lPrime[i + 1]
            lPrime[i + 1] = temp
            i += 2
        } else {
            i += 1
        }
    }
    return lPrime
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird3(l: [Int]) -> [Int] {
    var lPrime = l
    for i in 0..<lPrime.count {
        if lPrime[i] % 3 == 0 {
            let temp = lPrime[i]
            lPrime[i] = lPrime[i + 1]
            lPrime[i + 1] = temp
        }
    }
    return lPrime
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird4(l: [Int]) -> [Int] {
    var lPrime = l
    var i = 0
    while i < lPrime.count {
        if lPrime[i] % 3 == 0 {
            let temp = lPrime[i]
            lPrime[i] = lPrime[i + 1]
            lPrime[i + 1] = temp
            i += 2
        } else {
            i += 1
        }
    }
    return lPrime
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird5(l: [Int]) -> [Int] {
    var lPrime = l
    var i = 0
    while i < lPrime.count {

func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird5(l: [Int]) -> [Int] {
    var l = l
    var i = 0
   

func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird5(l: [Int]) -> [Int] {
    var l = l
    var i = 0
   

func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird5(l: [Int]) -> [Int] {
    var l = l
    var i = 0
   

func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

```swift
// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird2(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird3(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird4(l: [Int]) -> [Int] {
    var l = l
    var i = 0
    while i < l.count {
        if l[i] % 3 == 0 {
            let temp = l[i]
            l[i] = l[l.count - 1]
            l[l.count - 1] = temp
            l.removeLast()
        } else {
            i += 1
        }
    }
    return l
}

// This function takes an array l and returns an array l' such that
// l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
// to the values of the corresponding indicies of l, but sorted.
// sortThird(l: [1, 2, 3]) == [1, 2, 3]
// sortThird(l: [5, 6, 3, 4, 8, 9, 2]) == [2, 6, 3, 4, 8, 9, 5]
func sortThird5(l: [Int]) -> [Int] {
    var l = l
    var i = 0
   

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

func unique(l: [String]) -> [String] {
    var result = [String]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    var set = Set<T>()
    for i in l {
        if!set.contains(i) {
            set.insert(i)
            result.append(i)
        }
    }
    return result
}

func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    var set = Set<T>()
    for i in l {
        if!set.contains(i) {
            set.insert(i)
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Comparable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    var set = Set<T>()
    for i in l {
        if!set.contains(i) {
            set.insert(i)
            result.append(i)
        }
    }
    return result.sorted(by: isOrderedBefore)
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [String]) -> [String] {
    var result = [String]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    var set = Set<T>()
    for i in l {
        if!set.contains(i) {
            set.insert(i)
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    var set = Set<T>()
    for i in l {
        if!set.contains(i) {
            set.insert(i)
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    var set = Set<T>()
    for i in l {
        if!set.contains(i) {
            set.insert(i)
            result.append(i)
        }
    }
    return result.sorted(by: isOrderedBefore)
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    var set = Set<T>()
    for i in l {
        if!set.contains(i) {
            set.insert(i)
            result.append(i)
        }
    }
    return result.sorted(by: isOrderedBefore)
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    var set = Set<T>()
    for i in l {
        if!set.contains(i) {
            set.insert(i)
            result.append(i)
        }
    }
    return result.sorted(by: isOrderedBefore)
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
   

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    var unique = Set<Int>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    var unique = Set<Int>()
    for (k, v) in d {
        if!unique.contains(v) {
            result[k] = v
            unique.insert(v)
        }
    }
    return result
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    var unique = Set<Int>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]) == ["h": 0, "i": 123, "a": 5, "b": 3, "d": 2, "f": 3, "g": 9]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    var unique = Set<Int>()
    for (k, v) in d {
        if!unique.contains(v) {
            result[k] = v
            unique.insert(v)
        }
    }
    return result
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]) == ["h": 0, "i": 123, "a": 5, "b": 3, "d": 2, "f": 3, "g": 9]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    var unique = Set<Int>()
    for (k, v) in d {
        if!unique.contains(v) {
            result[k] = v
            unique.insert(v)
        }
    }
    return result
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]) == ["h": 0, "i": 123, "a": 5, "b": 3, "d": 2, "f": 3, "g": 9]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    var unique = Set<Int>()
    for (k, v) in d {
        if!unique.contains(v) {
            result[k] = v
            unique.insert(v)
        }
    }
    return result
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]) == ["h": 0, "i": 123, "a": 5, "b": 3, "d": 2, "f": 3, "g": 9]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    var unique = Set<Int>()
    for (k, v) in d {
        if!unique.contains(v) {
            result[k] = v
            unique.insert(v)
        }
    }
    return result
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]) == ["h": 0, "i": 123, "a": 5, "b": 3, "d": 2, "f": 3, "g": 9]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    var unique = Set<Int>()
    for (k, v) in d {
        if!unique.contains(v) {
            result[k] = v
            unique.insert(v)
        }
    }

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique(l: [String]) -> [String] {
    var result = [String]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Equatable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T>(l: [T], isEqual: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { isEqual(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Hashable>(l: [T], isEqual: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { isEqual(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Comparable>(l: [T], isEqual: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { isEqual(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [String]) -> [String] {
    var result = [String]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Equatable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T>(l: [T], isEqual: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { isEqual(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Hashable>(l: [T], isEqual: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { isEqual(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T], isEqual: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { isEqual(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9,

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    var unique = Set<Int>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

func unique(l: [String]) -> [String] {
    var result = [String]()
    var unique = Set<String>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    var unique = Set<T>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    var unique = Set<T>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

func unique<T: Equatable>(l: [T]) -> [T] {
    var result = [T]()
    var unique = Set<T>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    var unique = Set<Int>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: ["hello", "hello", "world", "foo", "bar", "foo", "bar"]) == ["bar", "foo", "hello", "world"]
func unique(l: [String]) -> [String] {
    var result = [String]()
    var unique = Set<String>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    var unique = Set<T>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: ["hello", "hello", "world", "foo", "bar", "foo", "bar"]) == ["bar", "foo", "hello", "world"]
func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    var unique = Set<T>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    var unique = Set<T>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: ["hello", "hello", "world", "foo", "bar", "foo", "bar"]) == ["bar", "foo", "hello", "world"]
func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    var unique = Set<T>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Equatable>(l: [T]) -> [T] {
    var result = [T]()
    var unique = Set<T>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: ["hello", "hello", "world", "foo", "bar", "foo", "bar"]) == ["bar", "foo", "hello", "world"]
func unique<T: Equatable>(l: [T]) -> [T] {
    var result = [T]()
    var unique = Set<T>()
    for i in l {
        if!unique.contains(i) {
            result.append(i)
            unique.insert(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 12

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    for (k, v) in d {
        if!result.contains(where: { $0.value == v }) {
            result[k] = v
        }
    }
    return result.sorted(by: { $0.key < $1.key })
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]) == ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    for (k, v) in d {
        if!result.contains(where: { $0.value == v }) {
            result[k] = v
        }
    }
    return result.sorted(by: { $0.key < $1.key })
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]) == ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    for (k, v) in d {
        if!result.contains(where: { $0.value == v }) {
            result[k] = v
        }
    }
    return result.sorted(by: { $0.key < $1.key })
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]) == ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    for (k, v) in d {
        if!result.contains(where: { $0.value == v }) {
            result[k] = v
        }
    }
    return result.sorted(by: { $0.key < $1.key })
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]) == ["a": 5, "b": 3, "c": 5, "d": 2, "e": 3, "f": 3, "g": 9, "h": 0, "i": 123]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    for (k, v) in d {
        if!result.contains(where: { $0.value == v }) {
            result[k] = v
        }
    }
    return result.sorted(by: { $0.key < $1.

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    for (k, v) in d {
        if!result.keys.contains(k) {
            result[k] = v
        }
    }
    return result.sorted(by: { $0.key < $1.key })
}

func unique(s: Set<Int>) -> [Int] {
    var result = [Int]()
    for i in s {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique(t: (Int, Int, Int, Int, Int, Int, Int, Int, Int, Int)) -> (Int, Int, Int, Int, Int, Int, Int, Int, Int, Int) {
    var result = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
    (result.0, result.1, result.2, result.3, result.4, result.5, result.6, result.7, result.8, result.9) = t
    return (
        result.0,
        result.1,
        result.2,
        result.3,
        result.4,
        result.5,
        result.6,
        result.7,
        result.8,
        result.9
    )
}

func unique(t: (Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int)) -> (Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int) {
    var result = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
    (result.0, result.1, result.2, result.3, result.4, result.5, result.6, result.7, result.8, result.9, result.10, result.11, result.12, result.13, result.14, result.15, result.16, result.17, result.18, result.19) = t
    return (
        result.0,
        result.1,
        result.2,
        result.3,
        result.4,
        result.5,
        result.6,
        result.7,
        result.8,
        result.9,
        result.10,
        result.11,
        result.12,
        result.13,
        result.14,
        result.15,
        result.16,
        result.17,
        result.18,
        result.19
    )
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in a dictionary
// unique(d: ["a": 1, "b": 2, "c": 1, "d": 3]) == ["a": 1, "b": 2, "c": 1, "d": 3]
func unique(d: [String: Int]) -> [String: Int] {
    var result = [String: Int]()
    for (k, v) in d {
        if!result.keys.contains(k) {
            result[k] = v
        }
    }
    return result.sorted(by: { $0.key < $1.key })
}

// Return sorted unique elements in a set
// unique(s: [1, 3, 5, 3, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(s: Set<Int>) -> [Int] {
    var result = [Int]()
    for i in s {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in a tuple
// unique(t: (1, 3, 5, 3, 2, 3, 3, 9, 0, 123)) == (0, 2, 3, 5, 9, 123)
func unique(t: (Int, Int, Int, Int, Int, Int, Int, Int, Int, Int)) -> (Int, Int, Int, Int, Int, Int, Int, Int, Int, Int) {
    var result = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
    (result.0, result.1, result.2, result.3, result.4, result.5, result.6, result.7, result.8, result.9) = t
    return (
        result.0,
        result.1,
        result.2,
        result.3,
        result.4,
        result.5,
        result.6,
        result.7,
        result.8,
        result.9
    )
}

// Return sorted unique elements in a tuple
// unique(t: (1, 3, 5, 3, 2, 3, 3, 9, 0, 123)) == (0, 2, 3, 5, 9, 123)
func unique(t: (Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int)) -> (Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int) {
    var result = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
    (result.0, result.1, result.2, result.3, result.4, result.5, result.6, result.7, result.8, result.9, result.10, result.11, result.12, result.13, result.14, result.15, result.16, result.17, result.18, result.19) = t
    return (
        result.0,
        result.1,
        result.2,
        result.3,
        result.4,
        result.5,
        result.6,
        result.7,
        result.8,
        result.9,
        result.10,
        result.11,
        result.12,
        result.13,
        result.14,
        result.15,
        result.16,
        result.17,
        result.18,
        result.19
    )
}

// Return sorted unique elements in a tuple
// unique(t: (1, 3, 5, 3,

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique(l: [String]) -> [String] {
    var result = [String]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Equatable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T>(l: [T], comparator: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { comparator(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

func unique<T: Hashable>(l: [T], comparator: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { comparator(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [String]) -> [String] {
    var result = [String]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Equatable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T>(l: [T], comparator: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { comparator(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T>(l: [T], comparator: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { comparator(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Hashable>(l: [T], comparator: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(where: { comparator(i, $0) }) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0,

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result.sorted()
}

// Return sorted unique

func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

func unique(l: [String]) -> [String] {
    var result = [String]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

func unique<T: Equatable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

func unique<T: Comparable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

func unique<T: Hashable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

func unique<T: Equatable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

```swift
// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [Int]) -> [Int] {
    var result = [Int]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique(l: [String]) -> [String] {
    var result = [String]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Hashable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Equatable>(l: [T]) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Hashable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Equatable>(l: [T], isOrderedBefore: (T, T) -> Bool) -> [T] {
    var result = [T]()
    for i in l {
        if!result.contains(i) {
            result.append(i)
        }
    }
    return result
}

// Return sorted unique elements in an array
// unique(l: [5, 3, 5, 2, 3, 3, 9, 0, 123]) == [0, 2, 3, 5, 9, 123]
func unique<T: Comparable>(l: [T], isOrderedBefore:

func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in l {
        if i > max {
            max = i
        }
    }
    return max
}

func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 0..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 0..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in l {
        if i < min {
            min = i
        }
    }
    return min
}

func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 0..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 0..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

func count(l: [Int], e: Int) -> Int {
    var count = 0
    for i in l {
        if i == e {
            count += 1
        }
    }
    return count
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in l {
        if i > max {
            max = i
        }
    }
    return max
}

// Return the index of the maximum element in the array.
// maxElementIndex(l: [1, 2, 3]) == 2
// maxElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 10
func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 0..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

// Return the maximum element and its index in the array.
// maxElementAndIndex(l: [1, 2, 3]) == (3, 2)
// maxElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (123, 10)
func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 0..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

// Return the minimum element in the array.
// minElement(l: [1, 2, 3]) == 1
// minElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -10
func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in l {
        if i < min {
            min = i
        }
    }
    return min
}

// Return the index of the minimum element in the array.
// minElementIndex(l: [1, 2, 3]) == 0
// minElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 3
func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 0..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

// Return the minimum element and its index in the array.
// minElementAndIndex(l: [1, 2, 3]) == (1, 0)
// minElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (-10, 10)
func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 0..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

// Return the number of occurrences of the given element in the array.
// count(l: [1, 2, 3, 1, 2, 3, 1, 2, 3], e: 1) == 3
// count(l: [1, 2, 3, 1, 2, 3, 1, 2, 3], e: 5) == 0
func count(l: [Int], e: Int) -> Int {
    var count = 0
    for i in l {
        if i == e {
            count += 1
        }
    }
    return count
}

// Return the number of occurrences of the given element in the array.
// count(l: [1, 2, 3, 1, 2, 3, 1, 2, 3], e: 1) == 3
// count(l: [

func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var index = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            index = i
        }
    }
    return index
}

func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var index = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            index = i
        }
    }
    return (max, index)
}

func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
        }
    }
    return min
}

func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var index = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            index = i
        }
    }
    return index
}

func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var index = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            index = i
        }
    }
    return (min, index)
}

func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == element {
            count += 1
        }
    }
    return count
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

// Return the index of the maximum element in the array.
// maxElementIndex(l: [1, 2, 3]) == 2
// maxElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 10
func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var index = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            index = i
        }
    }
    return index
}

// Return the maximum element and its index in the array.
// maxElementAndIndex(l: [1, 2, 3]) == (3, 2)
// maxElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (123, 10)
func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var index = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            index = i
        }
    }
    return (max, index)
}

// Return the minimum element in the array.
// minElement(l: [1, 2, 3]) == 1
// minElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -10
func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
        }
    }
    return min
}

// Return the index of the minimum element in the array.
// minElementIndex(l: [1, 2, 3]) == 0
// minElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 7
func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var index = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            index = i
        }
    }
    return index
}

// Return the minimum element and its index in the array.
// minElementAndIndex(l: [1, 2, 3]) == (1, 0)
// minElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (-10, 7)
func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var index = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            index = i
        }
    }
    return (min, index)
}

// Return the number of occurrences of the given element in the array.
// countOccurrences(l: [1, 2, 3, 2, 4, 2], element: 2) == 3
// countOccurrences(l: ["a", "b", "c", "a", "b", "c"], element: "b") == 2
func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == element {
            count += 1
        }
    }
    return count
}

// Return the number of occurrences of the given element in the array.
// countOccurrences(l: ["a", "b", "c", "a", "b", "c"], element: "b") == 2
// countOccurrences(

func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in l {
        if i > max {
            max = i
        }
    }
    return max
}

func secondMaxElement(l: [Int]) -> Int? {
    var max = l[0]
    var secondMax = l[0]
    for i in l {
        if i > max {
            secondMax = max
            max = i
        } else if i > secondMax {
            secondMax = i
        }
    }
    if max == secondMax {
        return nil
    } else {
        return secondMax
    }
}

func thirdMaxElement(l: [Int]) -> Int? {
    var max = l[0]
    var secondMax = l[0]
    var thirdMax = l[0]
    for i in l {
        if i > max {
            thirdMax = secondMax
            secondMax = max
            max = i
        } else if i > secondMax {
            thirdMax = secondMax
            secondMax = i
        } else if i > thirdMax {
            thirdMax = i
        }
    }
    if max == secondMax {
        return nil
    } else {
        return thirdMax
    }
}

func countElements(l: [Int], target: Int) -> Int {
    var count = 0
    for i in l {
        if i < target {
            count += 1
        }
    }
    return count
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in l {
        if i > max {
            max = i
        }
    }
    return max
}

// Return the second maximum element in the array.
// If the array has less than two elements, return nil.
// secondMaxElement(l: [1, 2, 3]) == nil
// secondMaxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 9
func secondMaxElement(l: [Int]) -> Int? {
    var max = l[0]
    var secondMax = l[0]
    for i in l {
        if i > max {
            secondMax = max
            max = i
        } else if i > secondMax {
            secondMax = i
        }
    }
    if max == secondMax {
        return nil
    } else {
        return secondMax
    }
}

// Return the third maximum element in the array.
// If the array has less than three elements, return nil.
// thirdMaxElement(l: [1, 2, 3]) == nil
// thirdMaxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 0
func thirdMaxElement(l: [Int]) -> Int? {
    var max = l[0]
    var secondMax = l[0]
    var thirdMax = l[0]
    for i in l {
        if i > max {
            thirdMax = secondMax
            secondMax = max
            max = i
        } else if i > secondMax {
            thirdMax = secondMax
            secondMax = i
        } else if i > thirdMax {
            thirdMax = i
        }
    }
    if max == secondMax {
        return nil
    } else {
        return thirdMax
    }
}

// Return the number of elements that are smaller than the target number.
// countElements(l: [1, 2, 3, 4, 5], target: 3) == 2
// countElements(l: [1, 2, 3, 4, 5], target: 6) == 0
func countElements(l: [Int], target: Int) -> Int {
    var count = 0
    for i in l {
        if i < target {
            count += 1
        }
    }
    return count
}

// Return the number of elements that are smaller than the target number.
// countElements(l: [1, 2, 3, 4, 5], target: 3) == 2
// countElements(l: [1, 2, 3, 4, 5], target: 6) == 0
func countElements(l: [Int], target: Int) -> Int {
    var count = 0
    for i in l {
        if i < target {
            count += 1
        }
    }
    return count
}

// Return the number of elements that are smaller than the target number.
// countElements(l: [1, 2, 3, 4, 5], target: 3) == 2
// countElements(l: [1, 2, 3, 4, 5], target: 6) == 0
func countElements(l: [Int], target: Int) -> Int {
    var count = 0
    for i in l {
        if i < target {
            count += 1
        }
    }
    return count
}

// Return the number of elements that are smaller than the target number.
// countElements(l: [1, 2, 3, 4, 5], target: 3) == 2
// countElements(l: [1, 2, 3, 4, 5], target: 6) == 0
func countElements(l: [Int], target: Int) -> Int {
    var count = 0
    for i in l {
        if i < target {
            count += 1
        }
    }
    return count
}

// Return the number of elements that are smaller than the target number.
// countElements(l: [1, 2, 3, 4, 5], target: 3) == 2
// countElements(l: [1, 2, 3, 4, 5], target: 6) == 0
func countElements(l: [Int],

func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
        }
    }
    return min
}

func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == element {
            count += 1
        }
    }
    return count
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

// Return the index of the maximum element in the array.
// maxElementIndex(l: [1, 2, 3]) == 2
// maxElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 10
func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

// Return the maximum element and its index in the array.
// maxElementAndIndex(l: [1, 2, 3]) == (3, 2)
// maxElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (123, 10)
func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

// Return the minimum element in the array.
// minElement(l: [1, 2, 3]) == 1
// minElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -10
func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
        }
    }
    return min
}

// Return the index of the minimum element in the array.
// minElementIndex(l: [1, 2, 3]) == 0
// minElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 1
func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

// Return the minimum element and its index in the array.
// minElementAndIndex(l: [1, 2, 3]) == (1, 0)
// minElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (-10, 1)
func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

// Return the number of occurrences of the given element in the array.
// countOccurrences(l: [1, 2, 3, 2, 4, 2], element: 2) == 3
func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == element {
            count += 1
        }
    }
    return count
}

// Return the index of the first occurrence of the given element in the array.
// firstOccurrence(l: [1, 2, 3, 2, 4, 2], element: 2) == 1
// firstOccurrence(l: [1, 2, 3, 2, 4, 2],

func maxElement(l: [Int]) -> Int {
    if l.count == 0 {
        return 0
    }
    
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

func maxElementIndex(l: [Int]) -> Int {
    if l.count == 0 {
        return 0
    }
    
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

func maxElementIndexLast(l: [Int]) -> Int {
    if l.count == 0 {
        return 0
    }
    
    var max = l[0]
    var maxIndex = 0
    var lastMax = max
    var lastMaxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            lastMax = max
            lastMaxIndex = maxIndex
            max = l[i]
            maxIndex = i
        } else if l[i] == max {
            lastMax = max
            lastMaxIndex = maxIndex
        }
    }
    return lastMaxIndex
}

func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    if l.count == 0 {
        return (0, 0)
    }
    
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

func maxElementAndIndexLast(l: [Int]) -> (Int, Int) {
    if l.count == 0 {
        return (0, 0)
    }
    
    var max = l[0]
    var maxIndex = 0
    var lastMax = max
    var lastMaxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            lastMax = max
            lastMaxIndex = maxIndex
            max = l[i]
            maxIndex = i
        } else if l[i] == max {
            lastMax = max
            lastMaxIndex = maxIndex
        }
    }
    return (lastMax, lastMaxIndex)
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    if l.count == 0 {
        return 0
    }
    
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

// Return the index of the first occurrence of the maximum element in the array.
// maxElementIndex(l: [1, 2, 3]) == 0
// maxElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 10
func maxElementIndex(l: [Int]) -> Int {
    if l.count == 0 {
        return 0
    }
    
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

// Return the index of the last occurrence of the maximum element in the array.
// maxElementIndex(l: [1, 2, 3]) == 0
// maxElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 10
func maxElementIndexLast(l: [Int]) -> Int {
    if l.count == 0 {
        return 0
    }
    
    var max = l[0]
    var maxIndex = 0
    var lastMax = max
    var lastMaxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            lastMax = max
            lastMaxIndex = maxIndex
            max = l[i]
            maxIndex = i
        } else if l[i] == max {
            lastMax = max
            lastMaxIndex = maxIndex
        }
    }
    return lastMaxIndex
}

// Return the maximum element and its index in the array.
// maxElementAndIndex(l: [1, 2, 3]) == (3, 2)
// maxElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (123, 10)
func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    if l.count == 0 {
        return (0, 0)
    }
    
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

// Return the maximum element and its index in the array.
// maxElementAndIndex(l: [1, 2, 3]) == (3, 2)
// maxElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (123, 10)
func maxElementAndIndexLast(l: [Int]) -> (Int, Int) {
    if l.count == 0 {
        return (0, 0)
    }
    
    var max = l[0]
    var maxIndex = 0
    var lastMax = max
    var lastMaxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            lastMax = max
            lastMaxIndex = maxIndex
            max = l[i]
            maxIndex = i
        } else if l[i] == max {
            lastMax = max
            lastMaxIndex = maxIndex
        }
    }
    return (lastMax, lastMaxIndex)
}

// Return the maximum element and its index in the array.
// maxElementAndIndex(l: [1, 2, 3]) == (3, 2)
// maxElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (123, 10)
func maxElementAndIndexFirst(l: [Int]) -> (Int, Int) {
    if l.count == 0 {
        return

func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
        }
    }
    return min
}

func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == element {
            count += 1
        }
    }
    return count
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

// Return the index of the maximum element in the array.
// maxElementIndex(l: [1, 2, 3]) == 2
// maxElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 10
func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

// Return the maximum element and its index in the array.
// maxElementAndIndex(l: [1, 2, 3]) == (3, 2)
// maxElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (123, 10)
func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

// Return the minimum element in the array.
// minElement(l: [1, 2, 3]) == 1
// minElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -10
func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
        }
    }
    return min
}

// Return the index of the minimum element in the array.
// minElementIndex(l: [1, 2, 3]) == 0
// minElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 1
func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

// Return the minimum element and its index in the array.
// minElementAndIndex(l: [1, 2, 3]) == (1, 0)
// minElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (-10, 1)
func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

// Return the number of occurrences of the given element in the array.
// countOccurrences(l: [1, 2, 3, 2, 4, 2], element: 2) == 3
// countOccurrences(l: ["a", "b", "c", "a", "b", "a"], element: "a") == 3
func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == element {
            count += 1
        }
    }
    return count
}

// Return the number of occurrences of the given element in the array.
// countOccurrences(l: ["apple", "banana", "cherry", "apple", "banana", "apple

func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in l {
        if i > max {
            max = i
        }
    }
    return max
}

func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 0..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 0..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in l {
        if i < min {
            min = i
        }
    }
    return min
}

func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 0..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 0..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in l {
        if i == element {
            count += 1
        }
    }
    return count
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in l {
        if i > max {
            max = i
        }
    }
    return max
}

// Return the index of the maximum element in the array.
// maxElementIndex(l: [1, 2, 3]) == 2
// maxElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 10
func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 0..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

// Return the maximum element and its index in the array.
// maxElementAndIndex(l: [1, 2, 3]) == (3, 2)
// maxElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (123, 10)
func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 0..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

// Return the minimum element in the array.
// minElement(l: [1, 2, 3]) == 1
// minElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -10
func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in l {
        if i < min {
            min = i
        }
    }
    return min
}

// Return the index of the minimum element in the array.
// minElementIndex(l: [1, 2, 3]) == 0
// minElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 1
func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 0..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

// Return the minimum element and its index in the array.
// minElementAndIndex(l: [1, 2, 3]) == (1, 0)
// minElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (-10, 1)
func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 0..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

// Return the number of occurrences of the given element in the array.
// countOccurrences(l: [1, 2, 3, 2, 4, 2], element: 2) == 3
// countOccurrences(l: ["a", "b", "a", "c", "a", "b"], element: "a") == 2
func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in l {
        if i == element {
            count += 1
        }
    }
    return count
}

// Return the number of occurrences of the given element in the array.
// countOccurrences(l: ["a", "b", "a", "c", "a", "b"], element: "a") == 2
// countOccurrences(l: ["a", "b", "a", "c", "a", "b"], element

func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

func firstIndexOf(l: [Int], target: Int) -> Int {
    for i in 0..<l.count {
        if l[i] == target {
            return i
        }
    }
    return -1
}

func lastIndexOf(l: [Int], target: Int) -> Int {
    var index = -1
    for i in 0..<l.count {
        if l[i] == target {
            index = i
        }
    }
    return index
}

func countGreater(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] > target {
            count += 1
        }
    }
    return count
}

func countSmaller(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] < target {
            count += 1
        }
    }
    return count
}

func countGreaterOrEqual(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] >= target {
            count += 1
        }
    }
    return count
}

func countSmallerOrEqual(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] <= target {
            count += 1
        }
    }
    return count
}

func countEqual(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == target {
            count += 1
        }
    }
    return count
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

// Return the index of the first element in the array that is equal to the given target.
// If there are no such elements, return -1.
// firstIndexOf(l: [1, 2, 3], target: 2) == 1
// firstIndexOf(l: [1, 2, 3], target: 4) == -1
func firstIndexOf(l: [Int], target: Int) -> Int {
    for i in 0..<l.count {
        if l[i] == target {
            return i
        }
    }
    return -1
}

// Return the index of the last element in the array that is equal to the given target.
// If there are no such elements, return -1.
// lastIndexOf(l: [1, 2, 3], target: 2) == 1
// lastIndexOf(l: [1, 2, 3], target: 4) == -1
func lastIndexOf(l: [Int], target: Int) -> Int {
    var index = -1
    for i in 0..<l.count {
        if l[i] == target {
            index = i
        }
    }
    return index
}

// Return the number of elements in the array that are greater than the given target.
// countGreater(l: [1, 2, 3], target: 2) == 1
// countGreater(l: [1, 2, 3], target: 4) == 0
func countGreater(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] > target {
            count += 1
        }
    }
    return count
}

// Return the number of elements in the array that are smaller than the given target.
// countSmaller(l: [1, 2, 3], target: 2) == 2
// countSmaller(l: [1, 2, 3], target: 4) == 0
func countSmaller(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] < target {
            count += 1
        }
    }
    return count
}

// Return the number of elements in the array that are greater than or equal to the given target.
// countGreaterOrEqual(l: [1, 2, 3], target: 2) == 2
// countGreaterOrEqual(l: [1, 2, 3], target: 4) == 0
func countGreaterOrEqual(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] >= target {
            count += 1
        }
    }
    return count
}

// Return the number of elements in the array that are smaller than or equal to the given target.
// countSmallerOrEqual(l: [1, 2, 3], target: 2) == 1
// countSmallerOrEqual(l: [1, 2, 3], target: 4) == 0
func countSmallerOrEqual(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] <= target {
            count += 1
        }
    }
    return count
}

// Return the number of elements in the array that are equal to the given target.
// countEqual(l: [1, 2, 3], target: 2) == 1
// countEqual(l: [1, 2, 3], target: 4) == 0
func countEqual(l: [Int], target: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == target {
            count += 1
        }
    }
    return count
}

// Return the number of elements in the array that are not equal to the given target.
// countNotEqual(l: [1, 2, 3], target: 2) == 2
// countNotEqual(l: [1, 2

func maxElement(l: [Int]) -> Int {
    if l.count == 1 {
        return l[0]
    } else {
        let mid = l.count / 2
        let leftMax = maxElement(l: Array(l[0..<mid]))
        let rightMax = maxElement(l: Array(l[mid..<l.count]))
        return max(leftMax, rightMax)
    }
}

func countElements(l: [Int], threshold: Int) -> Int {
    if l.count == 0 {
        return 0
    } else {
        let mid = l.count / 2
        if l[mid] > threshold {
            return 1 + countElements(l: Array(l[0..<mid]), threshold: threshold) + countElements(l: Array(l[mid+1..<l.count]), threshold: threshold)
        } else {
            return countElements(l: Array(l[0..<mid]), threshold: threshold) + countElements(l: Array(l[mid+1..<l.count]), threshold: threshold)
        }
    }
}

func sumElements(l: [Int]) -> Int {
    if l.count == 0 {
        return 0
    } else {
        let mid = l.count / 2
        return l[mid] + sumElements(l: Array(l[0..<mid])) + sumElements(l: Array(l[mid+1..<l.count]))
    }
}

func productElements(l: [Int]) -> Int {
    if l.count == 0 {
        return 1
    } else {
        let mid = l.count / 2
        return l[mid] * productElements(l: Array(l[0..<mid])) * productElements(l: Array(l[mid+1..<l.count]))
    }
}

func minElement(l: [Int]) -> Int {
    if l.count == 1 {
        return l[0]
    } else {
        let mid = l.count / 2
        let leftMin = minElement(l: Array(l[0..<mid]))
        let rightMin = minElement(l: Array(l[mid..<l.count]))
        return min(leftMin, rightMin)
    }
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    if l.count == 1 {
        return l[0]
    } else {
        let mid = l.count / 2
        let leftMax = maxElement(l: Array(l[0..<mid]))
        let rightMax = maxElement(l: Array(l[mid..<l.count]))
        return max(leftMax, rightMax)
    }
}

// Return the number of elements in the array that are greater than the threshold.
// countElements(l: [1, 2, 3], threshold: 1) == 2
// countElements(l: [1, 2, 3], threshold: 2) == 1
// countElements(l: [1, 2, 3], threshold: 3) == 0
func countElements(l: [Int], threshold: Int) -> Int {
    if l.count == 0 {
        return 0
    } else {
        let mid = l.count / 2
        if l[mid] > threshold {
            return 1 + countElements(l: Array(l[0..<mid]), threshold: threshold) + countElements(l: Array(l[mid+1..<l.count]), threshold: threshold)
        } else {
            return countElements(l: Array(l[0..<mid]), threshold: threshold) + countElements(l: Array(l[mid+1..<l.count]), threshold: threshold)
        }
    }
}

// Return the sum of all elements in the array.
// sumElements(l: [1, 2, 3]) == 6
// sumElements(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 122
func sumElements(l: [Int]) -> Int {
    if l.count == 0 {
        return 0
    } else {
        let mid = l.count / 2
        return l[mid] + sumElements(l: Array(l[0..<mid])) + sumElements(l: Array(l[mid+1..<l.count]))
    }
}

// Return the product of all elements in the array.
// productElements(l: [1, 2, 3]) == 6
// productElements(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -199999999999999960
func productElements(l: [Int]) -> Int {
    if l.count == 0 {
        return 1
    } else {
        let mid = l.count / 2
        return l[mid] * productElements(l: Array(l[0..<mid])) * productElements(l: Array(l[mid+1..<l.count]))
    }
}

// Return the minimum value in the array.
// minElement(l: [1, 2, 3]) == 1
// minElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -10
func minElement(l: [Int]) -> Int {
    if l.count == 1 {
        return l[0]
    } else {
        let mid = l.count / 2
        let leftMin = minElement(l: Array(l[0..<mid]))
        let rightMin = minElement(l: Array(l[mid..<l.count]))
        return min(leftMin, rightMin)
    }
}

// Return the maximum value in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    if l.count == 1 {
        return l[0]
    } else {
        let mid = l.count / 2
        let leftMax = maxElement(l: Array(l[0..<mid]))
        let rightMax = maxElement(l: Array(l[mid..<l.count]))
        return max(leftMax, rightMax)
    }
}

// Return the number of elements in

func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
        }
    }
    return min
}

func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == element {
            count += 1
        }
    }
    return count
}

```swift
// Return maximum element in the array.
// maxElement(l: [1, 2, 3]) == 3
// maxElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 123
func maxElement(l: [Int]) -> Int {
    var max = l[0]
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
        }
    }
    return max
}

// Return the index of the maximum element in the array.
// maxElementIndex(l: [1, 2, 3]) == 2
// maxElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 10
func maxElementIndex(l: [Int]) -> Int {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return maxIndex
}

// Return the maximum element and its index in the array.
// maxElementAndIndex(l: [1, 2, 3]) == (3, 2)
// maxElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (123, 10)
func maxElementAndIndex(l: [Int]) -> (Int, Int) {
    var max = l[0]
    var maxIndex = 0
    for i in 1..<l.count {
        if l[i] > max {
            max = l[i]
            maxIndex = i
        }
    }
    return (max, maxIndex)
}

// Return the minimum element in the array.
// minElement(l: [1, 2, 3]) == 1
// minElement(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == -10
func minElement(l: [Int]) -> Int {
    var min = l[0]
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
        }
    }
    return min
}

// Return the index of the minimum element in the array.
// minElementIndex(l: [1, 2, 3]) == 0
// minElementIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == 1
func minElementIndex(l: [Int]) -> Int {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return minIndex
}

// Return the minimum element and its index in the array.
// minElementAndIndex(l: [1, 2, 3]) == (1, 0)
// minElementAndIndex(l: [5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10]) == (-10, 1)
func minElementAndIndex(l: [Int]) -> (Int, Int) {
    var min = l[0]
    var minIndex = 0
    for i in 1..<l.count {
        if l[i] < min {
            min = l[i]
            minIndex = i
        }
    }
    return (min, minIndex)
}

// Return the number of occurrences of the given element in the array.
// countOccurrences(l: [1, 2, 3, 2, 4, 2], element: 2) == 3
func countOccurrences(l: [Int], element: Int) -> Int {
    var count = 0
    for i in 0..<l.count {
        if l[i] == element {
            count += 1
        }
    }
    return count
}

// Return the index of the first occurrence of the given element in the array.
// firstOccurrence(l: [1, 2, 3, 2, 4, 2], element: 2) == 1
// firstOccurrence(l: [1, 2, 3, 2, 4, 2],