15.三数之和.py

#
# @lc app=leetcode.cn id=15 lang=python3
#
# [15] 三数之和
#

# @lc code=start

class Solution:
    def threeSum(self, nums: List[int]) -> List[List[int]]:
        result = []
        if not nums or len(nums) < 3:
            return result
        nums = sorted(nums)
        nums_len = len(nums)
        for i in range(nums_len):
            if nums[i] > 0:
                return result
            if i > 0 and nums[i] == nums[i-1]:
                continue
            left = i + 1
            right = nums_len - 1
            while left < right:
                if (nums[i] + nums[left] + nums[right]) == 0:
                    result.append([nums[i], nums[left], nums[right]])
                    while (left < right and nums[left] == nums[left+1]):
                        left += 1
                    while (left < right and nums[right] == nums[right-1]):
                        right -= 1
                    left += 1
                    right -= 1
                elif (nums[i] + nums[left] + nums[right]) > 0:
                    right -= 1
                else:
                    left += 1

        return result
# @lc code=end