sum.py

class Solution:
    def threeSum(self, nums: List[int]) -> List[List[int]]:
        res = []
        nums.sort()
        length = len(nums)
        
        for i in range(length-2):
            if i>0 and nums[i]==nums[i-1]:
                continue
            l = i+1
            r = length-1
            
            while l<r :
                total = nums[i]+nums[l]+nums[r]
                if total < 0:
                    l=l+1
                elif total > 0:
                    r = r-1
                else :
                    res.append([nums[i],nums[l],nums[r]])
                    
                    while l<r and nums[l]==nums[l+1]:
                        l = l+1
                    while l<r and nums[r] == nums[r-1]:
                        r = r -1 
                    l = l+1
                    r = r -1
        return res