/// https://leetcode.com/problems/two-sum/
class Solution {
public:
    vector<int> twoSum(vector<int>& A, int target) {
        vector<int> ans;
        unordered_map<int,int> mymap;
        
        for(int i=0;i<A.size();i++){
            int search = target - A[i];
            
            if(mymap.find(search) == mymap.end()){
                mymap[A[i]] = i;
            }else{
                /// search value is present 
                ans.push_back(mymap[search]);
                ans.push_back(i);
                return ans;
            }
        }
        return ans;
    }
};