347.md

好像没什么好讲的，priority_queue的迭代器比较奇怪..

typedef pair<int, int> P;
struct cmp{
    bool operator() (P a, P b){
        return a.first > b.first;
    }
};
class Solution {
public:
    vector<int> topKFrequent(vector<int>& nums, int k) {
        sort(nums.begin(), nums.end());
        priority_queue<P, vector<P>, cmp> a;
        vector<int> ans;
        for(auto it = nums.begin(); it != nums.end(); ){
            int count = 1;
            while(*it == *(++it))
                count++;
            if(k > a.size())
                a.push(make_pair(count, *(it-1)));
            else if(count > a.top().first)
                a.pop(),a.push(make_pair(count, *(it-1)));
        }
        while(a.size())
            ans.push_back(a.top().second), a.pop();
        return ans;
    }
};