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.
Note:
The solution set must not contain duplicate triplets.
Example:
Given array nums = [-1, 0, 1, 2, -1, -4],
A solution set is:
[
[-1, 0, 1],
[-1, -1, 2]
]
class Solution:
def threeSum(self, nums: List[int]) -> List[List[int]]:
if len(nums) < 3:
return []
ans = []
nums.sort()
for i in range(0, len(nums)-2):
if i > 0 and nums[i-1] == nums[i]:
continue
left, right = i+1, len(nums)-1
while right > left:
s = nums[left] + nums[right] + nums[i]
if s == 0:
ans.append([nums[i], nums[left], nums[right]])
left += 1
right -= 1
while right > left and nums[left] == nums[left-1]:
left += 1
while right > left and nums[right] == nums[right+1]:
right -= 1
elif s < 0:
left += 1
else:
right -= 1
return ans