twoSum Algorithm : How to improve this?

Question

I felt like doing an algorithm and found this problem on leetcode

Given an array of integers, find two numbers such that they add up to a specific target num

Answer 1

An O(n) solution in c++ using hash map only exploiting Commutative rule of Addition in real numbers.

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