217. Contains Duplicate

class Solution {public:    bool containsDuplicate(vector<int>& nums) {        map<int,int>m;        for(int i=0;i<nums.size();i++)        {            m[nums[i]]++;        }        for(auto it=m.begin();it!=m.end();it++)        {            if((*it).second>=2)                return true;        }        return false;    }};