leetcode 215

简介

使用大顶堆 和快排实现
奇怪的是, 使用大顶堆还比快排慢.

code

class Solution {
public:
    int findKthLargest(vector<int>& nums, int k) {
        std::priority_queue<int> big_heap;   // 构造一个默认最大堆
        for(auto it: nums) {
            big_heap.push(it);
        }
        int num = 0;
        while(k){
            k--;
            num = big_heap.top();
            big_heap.pop();
        }
        return num;
    }
};

class Solution {
    public int findKthLargest(int[] nums, int k) {
        Arrays.sort(nums);
        return nums[nums.length-k];
    }
}

class Solution {
public:
    int findKthLargest(vector<int>& nums, int k) {
        sort(nums.begin(), nums.end());
        return nums[nums.size() - k];
        
    }
};