Leetcode 215. Kth Largest Element in an Array

Leetcode 215. Kth Largest Element in an Array

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题目描述

Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.

For example,
Given [3,2,1,5,6,4] and k = 2, return 5.

Note:
You may assume k is always valid, 1 ≤ k ≤ array’s length.

输入：一个数组及序数k
输出：数组中第K大的数

思路

利用数据结构堆，将数组压入堆中，并进行k次出堆操作。时间复杂度

代码

class Solution {
public:
    int findKthLargest(vector<int>& nums, int k) {
        priority_queue<int> pq;
        if(nums.size()==0) return 0;

        for(int i =0;i<nums.size();i++){
            pq.push(nums[i]);
        }

        for(int i =1;i<k;i++){
            if(pq.size()!=0)
                pq.pop();
        }

        return pq.top();

    }
};