Go语言实现快速排序

快速排序原理不再赘述，以下是golang实现。

其中，math/rand包中有个Perm方法：

Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [o,n).

返回一个有n个元素的，[0,n)范围内整数的伪随机排列的切片

func (r *Rand) Perm(n int) []int {
    m := make([]int, n)
    for i := 0; i < n; i++ {
        j := r.Intn(i+1)
        m[i] = m[j]
        m[j] = i
    }
    return m
}

package main

import (
    "fmt"
    "math/rand"
)

func main() {
    origin := rand.Perm(10)
	//origin := []int{5,6,7,4,5,6,8,3,5,8}
	fmt.Println("origin: ", origin)
	qsort(origin, 0, len(origin))
	fmt.Println("q-sort: ", origin)
}

func qsort(p []int, l,r int) {
	if r>l {
		mid := proc(p, l, r)
		qsort(p, l, mid)
		qsort(p, mid+1, r)
	}
}

func proc(p []int, l,r int) (i int) {
	v := p[l]
	i = l
	for j := i+1; j<r; j++ {
		if p[j] < v {
			i++
			p[i], p[j] = p[j], p[i]
		}
	}	
	p[i], p[l] = p[l], p[i]
	return i
}