ExtensionSorts.swift

extension Array {
    mutating func swapItems(itemAtIndex firstIndex: Index, withItemAtIndex secondIndex: Index) {
        if firstIndex != secondIndex {
            swap(&self[firstIndex], &self[secondIndex])
        }
    }
}

extension Sequence where Iterator.Element: Comparable {
    
    static func selectionSort(_ items: [Iterator.Element]) -> [Iterator.Element] {
        var results = items
        var length = results.count
        
        for i in 0..<length {
            var minIndex = i
            
            for j in i + 1..<length {
                if results[j] < results[minIndex] {
                    minIndex = j
                }
                
                results.swapItems(itemAtIndex: i, withItemAtIndex: minIndex)
            }
        }
        return results
    }
    
    
    static func insertionSort(_ items: [Iterator.Element]) -> [Iterator.Element] {
        var results = items
        
        let length = results.count
        
        for i in 1..<length {
            for j in stride(from: i, to: 0, by: -1) {
                if results[j] < results[j - 1] {
                    results.swapItems(itemAtIndex: j, withItemAtIndex: j - 1)
                } else {
                    break
                }
            }
        }
        return results
    }
}