leetcode 26

class Solution:
    def removeDuplicates(self, nums: List[int]) -> int:
        if not nums:
            return None
        j = 0
        for i in range(len(nums)):
            if i > 0 and nums[i] != nums[i-1]:
                nums[j] = nums[i]
                j = j+1
            if i == 0:
                j = j+1
            return j

有疑问 待更新