class Solution { public: vector<int> twoSum(vector<int>& nums, int target) { unordered_map<int, int> mp; for(int i = 0; i < nums.size(); i++){ if(mp.find(target - nums[i]) == mp.end()) mp[nums[i]] = i; else return {mp[target - nums[i]], i}; } return {-1, -1}; } };