【leetcode】26. Remove Duplicates from Sorted Array

一、题目描述(删除重复元素)

https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/

给定排序的数组nums，就地删除重复项，使每个元素只出现一次并返回新的长度。
不要为另一个数组分配额外的空间，必须通过使用O（1）额外内存修改输入数组来实现此目的。

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.

二、题目分析

删除重复元素，要求不能申请新的空间，哦原来要用两套下标呀，i和j，那就整吧

i为遍历下标，遍历整个数组，j为新数组下标，出现不同的数字，j增加1，不同的数字插入下标为j的数组中。（其实就是插在数组i前面部分，i已经遍历到后半截了，不会影响遍历的放心········）

三、代码实现

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class Solution:
    def removeDuplicates(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        if len(nums)==0:
            return 0
        l=len(nums)
        j=1
        for i in range(1,len(nums)):
            if nums[i]==nums[i-1]:
                l=l-1
            else:
                nums[j]=nums[i]
                j=j+1
        return l