java常用算法之快速排序

package com.zjp.start.sort;

import java.util.Arrays;

/**
* 快排
*/
public class QuickSort {
public static void main(String[] args) {
int[] arr = {10, 7, 2, 4, 7, 62, 3, 4, 2, 1, 8, 9, 19};
quickSort(arr, 0, arr.length - 1);
System.out.println(Arrays.toString(arr));
}

private static void quickSort(int[] arr, int left, int right) {
if (left > right) {
return;
}
int tmp = arr[left];
int i = left;
int j = right;
while (i < j) {
//从右至左寻找小于基数的值得索引
while (i < j && arr[j] >= tmp) {
j--;
}
//从左至右寻找大于基数的值的索引
while (i < j && arr[i] <= tmp) {
i++;
}
if (i < j) {
//交换位置
int a = arr[i];
arr[i] = arr[j];
arr[j] = a;
}
}
//交换基数和i的值
arr[left] = arr[i];
arr[i] = tmp;
//对左边的数组进行快排
quickSort(arr, left, i - 1);
//对右边的数组会进行快排
quickSort(arr, i + 1, right);
}
}