打卡群刷题总结0624——四数之和

class Solution(object):
    def fourSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[List[int]]
        """
        nums.sort()
        res = []
        for i in range(len(nums) - 3):
            if i > 0 and nums[i] == nums[i - 1]:
                continue
            for j in range(i + 1, len(nums) - 2):
                if j > i + 1 and nums[j] == nums[j - 1]:
                    continue

                l, r = j + 1, len(nums) - 1
                while l < r:
                    if l > j + 1 and nums[l] == nums[l - 1]:
                        l += 1
                        continue
                    if r < len(nums) - 1 and nums[r] == nums[r + 1]:
                        r -= 1
                        continue

                    sum_ijlr = nums[i] + nums[j] + nums[l] + nums[r]
                    if sum_ijlr == target:
                        res.append([nums[i], nums[j], nums[l], nums[r]])
                        l += 1
                        r -= 1
                    elif sum_ijlr < target:
                        l += 1
                    else:
                        r -= 1
        return res