leetcode347

class Solution {
public:
    static int cmp(const pair<int,int>& p1,const pair<int,int>&p2)
    {
        return p1.second > p2.second;
    }
    vector<int> topKFrequent(vector<int>& nums, int k) {
        map<int,int>mp;
        vector<int>ans;
        for(int i = 0;i<nums.size();i++)
        {
            mp[nums[i]]++;
        }
        vector<pair<int,int>>v;
        for(auto it = mp.begin();it!= mp.end();it++)
        {
            v.push_back(make_pair(it->first,it->second));
        }
        sort(v.begin(),v.end(),cmp);
        for(int i = 0;i<k;i++)
        {
            ans.push_back(v[i].first);
        }
        return ans;
    }
};