Contains Duplicate

 1 class Solution {
 2 public:
 3     bool containsDuplicate(vector<int>& nums) {
 4         map<int,int> mymap;
 5         int size=nums.size();
 6         for(int i=0;i<size;i++)
 7         {
 8             if(mymap.find(nums[i])==mymap.end())
 9             {
10                 mymap.insert(pair<int,int>(nums[i],1));
11                 
12             }
13             else
14             {
15                 return true;
16             }
17         }
18         
19         return false;
20     }
21 };