QuickSort.swift

func partition<T: Comparable>(inout array: [T], first: Int, last: Int) -> Int {
    let pivot = first
    let pivotVal = array[pivot]
    (array[first], array[pivot]) = (array[pivot], array[first])
    var i = first + 1
    var j = first + 1
    while j < last {
        if array[j] < pivotVal {
            (array[i], array[j]) = (array[j], array[i])
            i += 1
        }
        j += 1
    }
    (array[i-1], array[first]) = (array[first], array[i-1])
    return (i - 1)
}

func quicksort<T: Comparable>(inout array: [T], first: Int, last: Int) {
    if last-first<1 {return}
    let pivot = partition(&array, first: first, last: last)
    quicksort(&array, first: first, last: pivot)
    quicksort(&array, first: pivot+1, last: last)
}

var list = [ 3,9,8,4,6,10,2,5,7,1]
quicksort(&list, first: 0, last: list.count)