leetcode 347. Top K Frequent Elements

 1 struct PP
 2 {
 3     int val;
 4     int count;
 5 }te;
 6 
 7 bool cmp(PP a,PP b)
 8 {
 9     return a.count > b.count;
10 }
11 
12 class Solution {
13 public:
14     vector<int> topKFrequent(vector<int>& nums, int k) {
15         int n = nums.size();
16         vector<int> ans;
17         vector<PP> temp;
18         map<int,int> mp;
19         int i;
20         for(i = 0;i < n;i++){
21             mp[ nums[i] ]++;
22         }
23         for(map<int,int>::iterator it = mp.begin();it != mp.end();it++){
24             te.val = it -> first;
25             te.count = it -> second;
26             temp.push_back(te);
27         }
28         sort(temp.begin(),temp.end(),cmp);
29         for(i = 0;i < k;i++){
30             ans.push_back(temp[i].val);
31         }
32         return ans;
33     }
34 };