import java.util.Arrays;
import java.util.Random;

public class KuaiSuSort {
    public static void main(String[] args) {
        int []a=randomArray();
        System.out.println(Arrays.toString(a));
        System.out.println("==================================");
        sort(a,0,a.length-1);
        System.out.println("==================================");
        System.out.println(Arrays.toString(a));
    }

    private static void sort(int[] a, int lo, int hi) {
        /**
         * [77, 65, 79, 95, 37, 89, 98, 41, 84]
         * t=77
         * 
         *  low                             hi
         * [ 65, 79, 95, 37, 89, 98, 41, 84]
         *  i                              找<-j
         *  i                          找<-j
         *  
         */
        if(lo>=hi)return;//最简问题
        int i=lo;
        int j=hi;
        int t=a[lo];
        while(i<j)
        {
            //j向左找<=t的值
            while(a[j]>t&&j>i){
                j--;
            }
            a[i]=a[j];
            //i向右找>t的值
            while(a[i]<=t&&j>i)
            {
                i++;
            }
            a[j]=a[i];
        }
        a[i]=t;
        System.out.println(t);
        System.out.println("-------");
        System.out.println(Arrays.toString(a));
        sort(a,lo,i-1);
        sort(a,i+1,hi);
    }

    private static int[] randomArray() {
        //5+[0,6)随机长度的数组，填入100以内随机值
        int[] a=new int[new Random().nextInt(6)+5];
        for (int i = 0; i < a.length; i++) {
            a[i]=new Random().nextInt(100);
        }
        return a;
    }


}

运行结果

[54, 22, 44, 44, 70, 59]
==================================
54
-------
[44, 22, 44, 54, 70, 59]
44
-------
[44, 22, 44, 54, 70, 59]
44
-------
[22, 44, 44, 54, 70, 59]
70
-------
[22, 44, 44, 54, 59, 70]
==================================
[22, 44, 44, 54, 59, 70]