text: class Solution {
  public:
      vector<vector<int>> threeSum(vector<int>& nums) {
          sort(nums.begin(), nums.end());
          
          vector<vector<int>> ans;
          set<vector<int>> s;
          int n = nums.size();
          
          if(n < 3) return ans;
          
          for(int i = 0; i < n - 2; ++i) {
              int curr = nums[i];
              int left = i + 1;
              int right = n - 1;
              
              while(left < right) {
                  int csum = curr + nums[left] + nums[right];
                  
                  if(csum == 0) {
                      s.insert({curr, nums[left], nums[right]});
                      
                      while (left < right && nums[left] == nums[left + 1]) left++;
                      while (left < right && nums[right] == nums[right - 1]) right--;
                      
                      left++;
                      right--;
                  } else if(csum < 0) {
                      while (left < right && nums[left] == nums[left + 1]) left++;
                      left++;
                  } else {
                      while (left < right && nums[right] == nums[right - 1]) right--;
                      right--;
                  }
              }
              
          }
          
          for(auto x: s){
              ans.push_back(x);
          }
          
          return ans;
      }
  };