Leetcode: Two Sum

vector<int> twoSum(vector<int> &numbers, int target) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        vector<int> res;    int length = numbers.size();if(length < 2)return res;map<int,int> mp;for(int i = 0; i < length; ++i)mp[numbers[i]] = i;map<int,int>::iterator it = mp.end();for(int i = 0; i < length; ++i){it = mp.find(target - numbers[i]);if(it != mp.end()){res.push_back(min(i+1,it->second +1));res.push_back(max(i+1,it->second +1));break;}}return res;    }