func quicksort[arr: Array] : I64
    do_quicksort(arr, 0, Array.size(arr)-1)
    return 0

func do_quicksort[arr: Array, low: I64, high: I64] : I64
    if low < high
        let i: I64 = partition(arr, low, high)
        do_quicksort(arr, low, i - 1)
        do_quicksort(arr, i + 1, high)
    return 0

func partition[arr: Array, low: I64, high: I64] : I64
    let pivot: I64 = Array.nth(arr, high)
    let i: I64 = low - 1
    for j in low:high
        if Array.nth(arr, j) <= pivot
            i = i + 1
            let temp: I64 = Array.nth(arr, i)
            Array.set(arr, i, Array.nth(arr, j))
            Array.set(arr, j, temp)
    let temp: I64 = Array.nth(arr, i + 1)
    Array.set(arr, i + 1, Array.nth(arr, high))
    Array.set(arr, high, temp)
    return i + 1

func main[] : I64
    let arr: Array = [340, 252, 352, 117, 650, 652, 322, 175, 714, 268, 725, 664]

    for i in 0:Array.size(arr)
        print_i64(Array.nth(arr, i))
    print("------------")

    quicksort(arr)

    for i in 0:Array.size(arr)
        print_i64(Array.nth(arr, i))