package main

import (
    "fmt"
)

func QSort(arr []int, start int, end int) {
    var (
        key  int = arr[start]
        low  int = start
        high int = end
    )
    for {
        for low < high {
            if arr[high] < key {
                arr[low] = arr[high]
                break
            }
            high--
        }
        for low < high {
            if arr[low] > key {
                arr[high] = arr[low]
                break
            }
            low++
        }
        if low >= high {
            arr[low] = key
            break
        }
    }
    if low-1 > start {
        QSort(arr, start, low-1)
    }
    if high+1 < end {
        QSort(arr, high+1, end)
    }
}

func main() {
    arr := []int{5, 1, 3, 0, 9, 8, 7, 4, 6}
    fmt.Println(arr)
    QSort(arr, 0, len(arr)-1)
    fmt.Println(arr)
}