ComparableQuickSort.swift

func quicksort<T: Comparable>(var list: T[]) -> T[] {
    if list.count <= 1 {
        return list
    }

    let pivot = list[0]

    var smallerList = T[]()
    var equalList = T[]()
    var biggerList = T[]()

    for x in list {
        switch x {
            case let x where x < pivot:
                smallerList.append(x)
            case let x where x == pivot:
                equalList.append(x)
            case let x where x > pivot:
                biggerList.append(x)
            default:
                break
        }
    }

    return quicksort(smallerList) + equalList + quicksort(biggerList)
}