dsa-competitive-programming/leetcode/two-sum/TwoPass.cpp

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