[Swift]快速排序算法

快速排序算法 - Swift

func quickSortPartition(array : [Int], left : Int, right: Int, rise : Bool) ->([Int], Int)
{
    var i = left
    var j = right
    let key = array[i]
    
    var sortArray = array
    
    
    while (i < j) {
        
        while (i < j && (rise ? (key <= sortArray[j]) : (key >= sortArray[j])) ) {
            
            j -= 1;
        }
        guard i < j else {
            continue
        }
        
        sortArray[i] = sortArray[j];
        print(">>>\(sortArray) \(key) \(i)  \(j)")
        
        while (i < j && (rise ? (key >= sortArray[i]) : (key <= sortArray[i])) ) {
            
            i += 1;
        }
        guard i < j else {
            continue
        }
        
        sortArray[j] = sortArray[i];
        print("<<<\(sortArray) \(key) \(i)  \(j)")
    }
    
    sortArray[i] = key;
    
    return (sortArray, i)
}

func sortByFast(array : [Int], left : Int, right: Int, rise : Bool) -> [Int]
{
    guard left < right else {
        return array
    }
    
    var (sortArray, p) = quickSortPartition(array: array, left: left, right: right, rise: rise)
    
    print("left_Sort \(sortArray) left :\(left) right:\(p-1)")
    sortArray = sortByFast(array: sortArray, left: left, right: p-1, rise: rise)
    print("rightSort \(sortArray) left :\(p+1) right:\(right)")
    sortArray = sortByFast(array: sortArray, left: p+1, right: right, rise: rise)
    
    return sortArray
}

var sortByFast_list : [Int] = [86, 37, 56, 29, 92, 73, 15, 63, 30, 8];
let sortByFast_list_count = sortByFast_list.count
let sortByFast_list2 = sortByFast(array: sortByFast_list, left: 0, right: sortByFast_list_count-1 , rise: true)
let sortByFast_list3 = sortByFast(array: sortByFast_list, left: 0, right: sortByFast_list_count-1 , rise: false)

[8, 15, 29, 30, 37, 56, 63, 73, 86, 92]
[92, 86, 73, 63, 56, 37, 30, 29, 15, 8]

參考文章

iOS面試題系列之常見算法 白話經典算法系列之六 快速排序 快速搞定