java 实现 快速排序法

public class QuickSort {
public static void swap(int [] arr,int a,int b)
{
int t;
t =arr[a] ;
arr[a] =arr[b] ;
arr[b] =t ;
}
public static int Partition(int [] arr,int low,int high)
    {
        int pivot=arr[low];//采用子序列的第一个元素作为枢纽元素
        while (low < high)
        {
            //从后往前栽后一部分中寻找第一个小于枢纽元素的元素
            while (low < high && arr[high] >= pivot)
            {
                --high;
            }
            //将这个比枢纽元素小的元素交换到前一部分
            swap(arr,low, high);
            //从前往后在前一部分中寻找第一个大于枢纽元素的元素
            while (low <high &&arr [low ]<=pivot )
            {
                ++low ;
            }
            swap(arr,low, high);//把比这个枢纽元素大的元素交换到后半部分
           
        }
       
StringBuilder sb1 = new StringBuilder();
for(int t:arr) {
sb1.append(t).append(",");
}
System.out.println(sb1);

       
        return low ;//返回枢纽元素所在的位置
    }
public static void Sort(int [] a,int low,int high)
    {
        if (low <high )
        {
            int n=Partition (a ,low ,high );
            Sort (a ,low ,n );
            Sort (a ,n +1,high );
        }
    }

public static void main(String[] args) {
int [] test={5,66,77,3,44,8,921,23,50};
StringBuilder sb1 = new StringBuilder();
for(int t:test) {
sb1.append(t).append(",");
}
System.out.println(sb1);

Sort(test,0,test.length-1);

StringBuilder sb2 = new StringBuilder();
for(int m:test) {
sb2.append(m).append(",");
}
System.out.println(sb2);
}
}