twoSum Leetcode C++ solution - accompanying solution at www.carmencincotti.com

twoSum.cpp

// View accompanying article at www.carmencincotti.com/algorithms/leetcode/01-twosum

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        unordered_map<int, int> m;
        for(int i; i<nums.size();i++) {
            int complement = target-nums[i];
            if(m.find(complement) != m.end())
                return {i, m[complement]};
            else
                m[nums[i]] = i;
        }
        return {-1, -1}; // Needed to compile.
    }
};