快速排序

public static void main(String[] args) {

int[] a = {49,38,65,97,76,13,27,49,78,34,12,64,1,8};

System.out.println("---------排序之前----------");

for(int i=0;i<a.length;i++){

System.out.println(a[i]+" ");

}

//快速排序

quick(a);

System.out.println("---------排序之后----------");

        for (int i = 0; i < a.length; i++) {

            System.out.print(a[i]+" ");

        }

}

 

privatestaticvoid quick(int[] a){

if(a.length>0){

quickSort(a,0,a.length-1);

}

}

 

privatestaticvoid quickSort(int[] a,intlow,inthigh){

if(low<high){ //如果不加这个判断递归会无法退出堆栈溢出异常

int middle = getMiddle(a,low,high);

quickSort(a,0,middle-1);

quickSort(a,middle+1,high);

}

}

 

privatestaticint getMiddle(int[] a,intlow,inthigh){

int temp =a[low];//基准元素

while(low<high){

//找到比基准元素小的元素位置

    while(low<high && a[high]>=temp){

    high--;

    }

    a[low] = a[high];

    while(low<high && a[low]<=temp){

    low++;

    }

    a[high] = a[low];

}

a[low] = temp;

returnlow;

 

}