[java] 快速排序

package com.yune.demo;import java.util.Arrays;public class QuickSort2 {    public static void main(String[] args) {        int[] arr = {2,1,4,6,9,20,11};        quickSort(arr, 0, arr.length - 1);        System.out.println(Arrays.toString(arr));    }    public static void quickSort(int[] arr, int left, int right) {        if(left < right) {            int i = left, j = right;            int x = arr[left];            while(i < j && arr[j] >= x) {                j--;            }            if(i < j) {                arr[i] = arr[j];                i++;            }            while(i < j && arr[i] < x) {                i++;            }            if(i < j) {                arr[j] = arr[i];                j--;            }            arr[i] = x;            quickSort(arr, left, i -1);            quickSort(arr, i + 1, right);        }    }}