3sum.cpp

class Solution {
public:
    vector<vector<int>> threeSum(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        vector<vector<int>> result;

        for(int i = 0; i < nums.size(); i++){
            if(i > 0 && nums[i] == nums[i - 1])
                continue;
            
            int left = i + 1;
            int right = nums.size() - 1;
            
            while(left < right){
                int sum = nums[i] + nums[left] + nums[right];

                if(sum < 0)
                    left++;
                else if(sum > 0)
                    right--;
                else{
                    result.push_back({nums[i], nums[left], nums[right]});

                    while(left < right && nums[left] == nums[left + 1])
                        left++;
                    while(left < right && nums[right] == nums[right - 1])
                        right--;
                    left++;
                    right--;
                }
            }
        }

        return result;
    }
};