Find the Kth largest number in the array

 

Title description

There is an array of integers. Please find the K-th largest number in the array according to the idea of ​​quick sort.

Given an integer array a, given its size n and the K you are looking for (K is between 1 and n), please return the Kth largest number to ensure that the answer exists.

Example 1

enter

[1,3,5,2,2],5,3

return value

2

代码实现：

import java.util.*;

public class Solution {
    public int findKth(int[] a, int n, int K) {
       PriorityQueue<Integer> queue = new PriorityQueue<>();
        for (int i = 0; i < K; i++) {
            queue.add(a[i]);
        }
        for (int i = K; i< n; i++) {
            if (a[i] > queue.peek()) {
                queue.poll();
                queue.add(a[i]);
            }
        }
        return queue.poll();
    }
}