quick sort for golang

quick_sort.go

package main

import (
	"math/rand"
	"sort"
	"time"
)

func main() {
	slice := rand.Perm(1000)

	QuickSort(slice)

	sorted := sort.SliceIsSorted(slice, func(i, j int) bool {
		return slice[i] < slice[j]
	})
	if !sorted {
		panic("not sorted")
	}
}

// QuickSort is quick sort
// TODO: three way quick sort
func QuickSort(src []int) {
	rand.Seed(time.Now().UnixNano())
	quickSort(src, 0, len(src)-1)
}

func quickSort(src []int, l, r int) {
	if l >= r {
		return
	}
	pos := partition(src, l, r)
	quickSort(src, l, pos-1)
	quickSort(src, pos+1, r)
}

func partition(src []int, l, r int) int {
	pos := rand.Intn(r-l+1) + l
	src[pos], src[l] = src[l], src[pos]

	pivot := src[l]
	j := l
	for i := l + 1; i <= r; i++ {
		if src[i] < pivot {
			j++
			src[j], src[i] = src[i], src[j]
		}
	}

	src[l], src[j] = src[j], src[l]
	return j
}