Returns three numbers from an array that add up to 0

threeSum.cpp

#include<iostream>
#include<vector>
#include<unordered_set>
#include<unordered_map>
using namespace std;

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

int main(){
    vector<int>v={-1, 0, 1, 2, -1, -4};
    auto vv=Solution().threeSum(v);
    for(int i:vv)
        cout<<i<<" ";
}