快速排序

class QuickSort{

    int partition(int[] a,int low,int high){
        int pivot = a[low]; //第一个元素作为枢轴
        while (low < high){ //用low、high搜索枢轴的位置
            while (low < high && a[high] >= pivot)
                high--;
            a[low] = a[high];//比枢轴小的元素移动到左端
            while (low < high && a[low] < pivot)
                low++;
            a[high] = a[low];//比枢轴大的元素移动到右端
        }
        a[low] = pivot;//枢轴元素放到最终位置
        return low;
    }
    public void sort(int[] a,int low,int high){
        
        if (low < high)//递归跳出的条件
        {
            int pivotpos = partition(a,low,high);//划分
            sort(a,low,pivotpos-1);//划分左子表
            sort(a,pivotpos+1,high);//划分右子表
        }
    }
}