[数据结构与算法]快速排序算法

package sort;

import org.junit.jupiter.api.Test;

/**
 * @Author fandayong001
 * @Date 2021-08-04
 * @description
 */
public class FastSortMy {

    int[] arr = new int[]{4,5,7,2,3,9,8,6,8,5};

    @Test
    public void test(){
        quickSort(arr, 0, arr.length - 1);
        for (int i = 0; i < arr.length; i++) {
            System.out.println(arr[i]);
        }
    }

    /**
     * 快排怎么排的
     * @param arr
     * @param low
     * @param high
     */
    public void quickSort(int[] arr,int low,int high){
        if(low>high){
            return;
        }
        int i,j,temp,t;
        i = low;
        j = high;
        temp = arr[low];
        // 先找出中间的值再去快排左和右
        while(i<j){
            while(arr[j]>temp&&i<j){
                j--;
            }
            while(arr[i]<=temp&&i<j){
                i++;
            }
            if(i!=j){
                t = arr[j];
                arr[j] = arr[i];
                arr[i] = t;
            }
        }
        arr[low] = arr[i];
        arr[i] = temp;
        quickSort(arr,low,i-1);
        quickSort(arr,i+1,high);
    }
}