LeetCode 215. Kth Largest Element in an Array

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.

Example 1:

Input: [3,2,1,5,6,4] and k = 2
Output: 5

Example 2:

Input: [3,2,3,1,2,4,5,5,6] and k = 4
Output: 4

题目思路

代码 C++

• 思路一、注意不能用 set ，set不允许有重复元素

class Solution {
public:
    int findKthLargest(vector& nums, int k) {
        multiset temp;
        
        for(int i=0; i < k; i++){
            temp.insert(nums[i]);
        }
        
        for(int i=k; i < nums.size(); i++){
            auto tt = temp.begin();
            if(*tt < nums[i]){
                temp.erase(tt);
                temp.insert(nums[i]);
            }
        }
        
        auto tt = temp.begin();
        return *tt;
    }
};

总结展望