4Sum Python Solution with Tests

lcpy gen -n 18   # by problem number
lcpy gen -s four_sum   # by problem name

Input: nums = [1,0,-1,0,-2,2], target = 0
Output: [[-2,-1,1,2],[-2,0,0,2],[-1,0,0,1]]

Input: nums = [2,2,2,2,2], target = 8
Output: [[2,2,2,2]]

class Solution:
    # Time: O(n^3)
    # Space: O(1) (excluding output)
    def four_sum(self, nums: list[int], target: int) -> list[list[int]]:
        nums.sort()
        result: list[list[int]] = []
        n = len(nums)

        for i in range(n - 3):
            if i > 0 and nums[i] == nums[i - 1]:
                continue
            for j in range(i + 1, n - 2):
                if j > i + 1 and nums[j] == nums[j - 1]:
                    continue
                left, right = j + 1, n - 1
                while left < right:
                    total = nums[i] + nums[j] + nums[left] + nums[right]
                    if total == target:
                        result.append([nums[i], nums[j], nums[left], nums[right]])
                        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 total < target:
                        left += 1
                    else:
                        right -= 1
        return result