LeetCode重点题系列之【26. Remove Duplicates from Sorted Array】

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本文介绍了一个使用双向双指针技术的高效算法，该算法能在原地修改输入数组以移除重复元素，并返回新长度。文章通过两个实例展示了如何在不使用额外空间的情况下，确保每个元素只出现一次。

Given a sorted array nums, remove the duplicates in-placesuch that each element appear only once and return the new length.

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

Example 1:

Given nums = [1,1,2],

Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively.

It doesn't matter what you leave beyond the returned length.

Example 2:

Given nums = [0,0,1,1,1,2,2,3,3,4],

Your function should return length = 5, with the first five elements of nums being modified to 0, 1, 2, 3, and 4 respectively.

It doesn't matter what values are set beyond the returned length.

This question should use two pointers(单向双指针)

class Solution(object):
    def removeDuplicates(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        slow=fast=0
        while fast<len(nums):
            while fast<len(nums) and nums[fast]==nums[slow]:
                fast+=1
            while fast<len(nums) and nums[fast]!=nums[slow]:
                slow+=1
                nums[slow]=nums[fast]
                fast+=1
            if fast==len(nums):
                return slow+1