leetcode-cpp/0015-3sum.cpp at main · j414j/leetcode-cpp · GitHub

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#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;

class Solution
{
public:
    vector<vector<int>> threeSum(vector<int> &nums)
    {
        vector<vector<int>> ans;
        sort(nums.begin(), nums.end());
        int n = nums.size();
        for (int i = 0; i < n; i++)
        {
            if (i == 0 || (i > 0 && nums[i] != nums[i - 1]))
            {
                int j = i + 1, k = n - 1;
                while (j < k)
                {
                    int sum = nums[i] + nums[j] + nums[k];
                    if (sum == 0)
                    {
                        ans.push_back(vector<int>{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 ans;
    }
};

int main()
{
    // vector<int> ques{-1, 0, 1, 2, -1, -4};
    // vector<int> ques{1, 1, 0};
    // vector<int> ques{-1, 0, 1, 2, -1, -4};
    vector<int> ques{0, 0, 0, 0};

    vector<vector<int>> ans = (new Solution())->threeSum(ques);
    return 0;
}