编辑代码

class Main {
	public static void main(String[] args) {
        int[] arr = {11,8,3,9,7,1,2,5};
        int result = quickSort(arr,0,arr.length-1,1);
        System.out.print(result);
	}


    public static int quickSort(int[] arr,int start,int end,int k){
        if(end<start){
            return -1;
        }
        int standard = arr[start];
        int i = start;
        int j = end;
        
        while(i<j){
            while(i<j&&arr[j]<=standard){
                j--;
            }
            if(i<j)
                arr[i++] = arr[j];
            
            while(i<j&&arr[i]>=standard){
                i++;
            }
            if(i<j)
                arr[j--] = arr[i];
        }
        arr[i] = standard;
        if(i==k) return arr[i];
        else if(i<k) return quickSort(arr,i+1,end,k);           //返回
        else return quickSort(arr,start,i-1,k);
    }
}