Leetcode 15.三数之和

解法：两处去重+二分法

class Solution:def threeSum(self, nums: List[int]) -> List[List[int]]:nums.sort()res = []visited_numi = [] # 第一处去重for i in range(len(nums) - 2):if nums[i] not in visited_numi:visited_numi.append(nums[i])sortnums = nums[i+1: ]l, r = 0, len(sortnums) - 1while r > l:if sortnums[l] + sortnums[r] == - nums[i]: res.append([nums[i], sortnums[l], sortnums[r]])while l < r and sortnums[l + 1] == sortnums[l]: l += 1 # 第二处去重while l < r and sortnums[r - 1] == sortnums[r]: r -= 1l += 1r -= 1elif sortnums[l] + sortnums[r] > - nums[i]: r -= 1else: l += 1return res