Trial

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {

        unordered_multimap <int, int> m;

        for(int i = 0; i<nums.size(); i++){
            m.insert({nums[i],i});
        }

        for(auto it= m.begin(); it!=m.end(); it++){
            int rem = target - it->first;

            if(m.find(rem)!=m.end() && it->second != m.find(rem)->second){
                return {it->second, m.find(rem)->second};
            }

        }

        return {};

    }
};