def fourSum(self, nums: List[int], target: int) -> List[List[int]]:

ans = []

if nums is not None and len(nums) >= 4:

length = len(nums)

nums = sorted(nums)

for i in range(length - 3):

if i > 0 and nums[i] == nums[i - 1]:

continue

for j in range(i + 1, length - 2):

if j > i + 1 and nums[j] == nums[j - 1]:

continue

left, right = j + 1, length - 1

while left < right:

if nums[i] + nums[j] + nums[left] + nums[right] == target:

oneAns = [nums[i], nums[j], nums[left], nums[right]]

ans.append(oneAns)

left += 1

right -= 1

while left < right and nums[left] == nums[left - 1]:

left += 1

while left < right and nums[right] == nums[right + 1]:

right -= 1

elif nums[i] + nums[j] + nums[left] + nums[right] < target:

left += 1

while left < right and nums[left] == nums[left - 1]:

left += 1

else:

right -= 1

while left < right and nums[right] == nums[right + 1]:

right -= 1