***Leetcode 692. Top K Frequent Words

Posted 2022-12-14 Z-Pilgrim

https://leetcode.com/problems/top-k-frequent-words/description/

用于练习优先队列了。。实际排序也行

struct cmp 
  bool operator() (const auto& a, const auto&b) 
      if (a.second != b.second) return a.second < b.second;
      return a.first > b.first;
    
;

class Solution 
public:
    vector<string> topKFrequent(vector<string>& words, int k) 
        priority_queue< pair<string, int>, vector< pair<string, int> >, cmp > q;
        unordered_map< string, int > mp;
        for (int i = 0; i < words.size(); i++) 
            mp[ words[i] ] ++;
        
        for (auto p: mp) 
            q.push( make_pair(p.first, p.second) );
        
        vector<string> ret;
        while (!q.empty()) 
            ret.push_back( q.top().first );
            q.pop();
            if (ret.size() >= k) break;
        
        return ret;
    
;