15-3Sum.py

# region Sliding Window
# Space O(n)
# Time O(n)
class Solution:
    def threeSum(self, nums: List[int]) -> List[List[int]]:
        nums.sort()
        retVal = []

        for i in range(len(nums) - 2):
            if i > 0 and nums[i] == nums[i - 1]:
                continue

            left, right = i + 1, len(nums) - 1

            while left < right:
                total = nums[i] + nums[left] + nums[right]

                if total == 0:
                    retVal.append([nums[i], nums[left], nums[right]])
                    left += 1
                    right -= 1
                    while nums[left] == nums[left - 1] and left < right:
                        left += 1
                    while nums[right] == nums[right + 1] and left < right:
                        right -= 1
                elif total < 0:
                    left += 1
                else:
                    right -= 1
        return retVal


# endregion