leetcode 3Sum python

# sort the array
# loop from i = 0 
# then left=i+1 right=len(nums)-1
# try nums[i] - ( nums[left]+nums[right]) = 0 
# 


class Solution(object):
    def threeSum(self, nums):
        """
        :type nums: List[int]
        :rtype: List[List[int]]
        """
        res=list()
        nums.sort()
        if len(nums) <= 2:
            return res
        
        for index in range(len(nums)-2):
            if index == 0 or nums[index] > nums[index-1]:
                left=index+1
                right=len(nums)-1
                while left < right:
                    if nums[left] + nums[right] == -nums[index]:
                        res.append( [nums[index],nums[left],nums[right] ] )
                        left+=1
                        right-=1
　　　　　　　　　　　　　　#ensure no repeat value
                        while left<right and nums[left] == nums[left-1]:
                            left+=1
                        while left < right and nums[right] == nums[right+1]:
                            right-=1
                    elif nums[left] + nums[right] < -nums[index]:
                        
                        while left < right:
                            left+=1
                            if nums[left] != nums[left-1]:
                                break
                    else:
                        while left < right:
                            right-=1
                            if nums[right] != nums[right+1]:
                                break
        return res