leetcode692 Top K Frequent Words

思路：

堆。
实现：

 #include <bits/stdc++.h>
 using namespace std;

 class Solution
 {
 public:
     inline bool cmp(pair<int, string> a, pair<int, string> b)
     {
         if (a.first > b.first) return true;
         if (a.first == b.first && a.second < b.second) return true;
         return false;
     }
     struct cmp1
     {
         bool operator()(const pair<int, string>& a, const pair<int, string>& b) const
         {
             if (a.first > b.first) return true;
             if (a.first == b.first && a.second < b.second) return true;
             return false;
         }
     };
     vector<string> topKFrequent(vector<string>& words, int k)
     {
         unordered_map<string, int> mp;
         for (auto it : words) mp[it]++;
         priority_queue<pair<int, string>, vector<pair<int, string>>, cmp1> q;
         int cnt = ;
         for (auto it : mp)
         {
             pair<int, string> tmp(it.second, it.first);
             if (cnt < k)
             {
                 q.push(tmp);
             }
             else if (cmp(tmp, q.top()))
             {
                 q.push(tmp);
                 q.pop();
             }
             cnt++;
         }
         vector<string> ret;
         while (!q.empty())
         {
             ret.push_back(q.top().second); q.pop();
         }
         reverse(ret.begin(), ret.end());
         return ret;
     }
 };
 int main()
 {
     vector<string> v = {"i", "love", "leetcode", "i", "love", "coding"};
     vector<string> ret = Solution().topKFrequent(v, );
     for (auto it : ret)
     {
         cout << it << " ";
     }
     cout << endl;
     return ;
 }