Solution.py

class Solution:
    def threeSum(self, nums: List[int]) -> List[List[int]]:
        n, res = len(nums), []
        if n < 3:
            return res
        nums.sort()
        for i in range(n - 2):
            if nums[i] > 0:
                break
            if i > 0 and nums[i] == nums[i - 1]:
                continue
            j, k = i + 1, n - 1
            while j < k:
                if nums[i] + nums[j] + nums[k] == 0:
                    res.append([nums[i], nums[j], nums[k]])
                    j += 1
                    k -= 1
                    while j < n and nums[j] == nums[j - 1]:
                        j += 1
                    while k > i and nums[k] == nums[k + 1]:
                        k -= 1
                elif nums[i] + nums[j] + nums[k] < 0:
                    j += 1
                else:
                    k -= 1
        return res