快速排序算法原理：

b站https://b23.tv/uJqRYN

package main

import "fmt"

//[]int{1,2,3,4,5,6,7,8}
func qsort(ori []int) []int {

	copy := append([]int{}, ori...)

	var inner func(ori []int)
	inner = func(ori []int) {

		if len(ori) == 0 || len(ori) == 1 {
			return
		}
		//找一个参考点最左边 元素个数>=2之后进行比较
		ref := ori[0]
		var i, j int
		loopj := true
		for i, j = 0, len(ori)-1; i != j; {
			if loopj {
				if ori[j] < ref {
					ori[i] = ori[j]
					i++ //该位置已经替换需要更新
					loopj = false
				} else {
					j--
				}
			} else {
				if ori[i] > ref {
					ori[j] = ori[i]
					j--
					loopj = true
				} else {
					i++
				}
			}
		}
		ori[i] = ref

		inner(ori[0:i])
		//if i < len(ori) {
		inner(ori[i+1:]) //equal ori[i+1:len(ori)]
		//	}

	}
	inner(copy)
	return copy

}

/*
ori = []int{1, 4, 3, 2}
output = []int{1,2,3,4}
*/
func main() {

	ori := []int{1, 4, 3, 2}
	fmt.Println(qsort(ori))

}