Competitive_Programming/LeetCode/15.3Sum.cpp at master · Pankajcoder1/Competitive_Programming · GitHub

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/*
    written by Pankaj Kumar.
    country:-INDIA
*/
typedef long long ll ;
const ll INF=1e18;
const ll mod1=1e9+7;
const ll mod2=998244353;
//Add main code here

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

        for (int i = 0; i < n; i++)
        {
            if (i > 0 && nums[i] == nums[i - 1])
                continue;
            int j = i + 1, k = n - 1;
            while (j < k)
            {
                int sum = nums[i] + nums[j] + nums[k];
                if (sum == 0)
                {
                    res.push_back({nums[i], nums[j], nums[k]});
                    while (j < k && nums[j] == nums[j + 1])
                        j++;
                    while (j < k && nums[k] == nums[k - 1])
                        k--;
                    j++;
                    k--;
                }
                else if (sum < 0)
                {
                    j++;
                }
                else
                {
                    k--;
                }
            }
        }

        return res;
    }
};