Untitled

#define ll long long
class Solution {
public:
    vector<vector<int>> threeSum(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        int n = nums.size();
        
        vector< vector<int> > output;
        unordered_set<ll> triplets;
            
        for(int i=0;i<n;i++) {
            int l = i + 1, r = n - 1;
            while (l < r) {
                int sum = nums[i] + nums[l] + nums[r];
                if (sum == 0) {
                    ll hash = (ll)nums[i] * 1e10L + (ll)nums[l] * 1e5L + (ll)nums[r];
                    if (triplets.find(hash) == triplets.end()) {
                        vector<int> aux{ nums[i], nums[l], nums[r] };
                        output.push_back(aux);
                        triplets.insert(hash);
                    }
                    l++, r--;
                } else if (sum < 0)
                    l++;
                else
                    r--;
            }
        }
        return output;
    }
};