1. #解1
    2. class Solution:
    3.     def removeDuplicates(self, nums: List[int]) -> int:
    4.         i = 1
    5.         while i < len(nums):
    6.             while i < len(nums) and nums[i] == nums[i-1]:
    7.                 del nums[i]
    8.             i += 1
    9.         return len(nums)
    12. #解2  用指针（下标），时间复杂度贼小 
    13. class Solution:
    14.     def removeDuplicates(self, nums: List[int]) -> int:
    15.         if not nums:
    16.             return 0
    18.         n = len(nums)
    19.         fast = slow = 1
    20.         while fast < n:
    21.             if nums[fast] != nums[fast - 1]:
    22.                 nums[slow] = nums[fast]
    23.                 slow += 1
    24.             fast += 1
    26.         return slow
    28. #解2.5 我写的仿照上面的，不知道为什么时间复杂度低一点
    29. class Solution:
    30.     def removeDuplicates(self, nums: List[int]) -> int:
    31.         slow = 1; fast = 1
    32.         while fast < len(nums):
    33.             if nums[fast] == nums[fast-1]:
    34.                 fast += 1
    35.             else:
    36.                 nums[slow] = nums[fast]
    37.                 fast += 1
    38.                 slow += 1
    39.         return slow