Given an array nums of n integers, are there elements a, b, c in nums such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.
Notice that the solution set must not contain duplicate triplets.
Example 1:
Input: nums = [-1,0,1,2,-1,-4]
Output: [[-1,-1,2],[-1,0,1]]
Example 2:
Input: nums = []
Output: []
Example 3:
Input: nums = [0]
Output: []
class Solution:
def threeSum(self, nums: List[int]) -> List[List[int]]:
nums.sort()
ans = list()
for i in range(len(nums) - 2):
if i > 0:
if nums[i] == nums[i-1]:
continue
left = i + 1
right = len(nums) - 1
while left < right:
accu = nums[i] + nums[left] + nums[right]
if accu == 0:
ans.append([nums[i], nums[left], nums[right]])
right -= 1
left += 1
while left < right and nums[left] == nums[left-1]:
left += 1
elif accu < 0:
left += 1
else: # accu > 0
right -= 1
return ans