每日一题--三数之和

class Solution:
    def threeSum(self, nums: List[int]) -> List[List[int]]:
        res = []
        nums.sort()
        n = len(nums)
        for i in range(n):
            if nums[i] > 0: return res
            if i>0 and nums[i] == nums[i-1]: continue
            L = i+1
            R = n - 1
            while(L < R):
                if nums[i] + nums[L] + nums[R] == 0:
                    res.append([nums[i], nums[L], nums[R]])
                    while L < R and nums[L] == nums[L+1]:
                        L+=1
                    while L < R and nums[R] == nums[R-1]:
                        R-=1
                    L += 1
                    R -= 1
                elif nums[i] + nums[L] + nums[R] > 0:
                    R -= 1
                else: 
                    L += 1
        return res