GFG PTOD | 28 Dec | Find All Triplets with Zero Sum

vector<vector<int>> findTriplets(vector<int> &arr) {
        // Code here
        // Set to handle duplicates
    set<vector<int>> resSet;
    int n = arr.size();
    unordered_map<int, vector<pair<int, int>>> mp;

    // Store sum of all the pairs with their indices
    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++)
            mp[arr[i] + arr[j]].push_back({i, j});
    }

      for (int i = 0; i < n; i++) {

        // Find remaining value to get zero sum
        int rem = -arr[i];
        if (mp.find(rem) != mp.end()) {
            vector<pair<int, int>> pairs = mp[rem];
            for (auto p : pairs) {
              
                  // Ensure no two indices are same in triplet
                if (p.first != i && p.second != i) {
                    vector<int> curr = {i, p.first, p.second};
                    sort(curr.begin(), curr.end());
                    resSet.insert(curr);
                }
            }
        }
    }

    vector<vector<int>> res(resSet.begin(), resSet.end());
    return res;
    }