LeetCode-26. Remove Duplicates from Sorted Array

[ninehills]

问题

https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/
Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.

Do not allocate extra space for another array, you must do this in place with constant memory.

For example,
Given input array 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 new length.

思路

刚开始以为就是算出去除重复后的长度，但是报wrong answer，看评论才知道要求同时修改list，思路为双指针法

解答

class Solution(object):
    def removeDuplicates(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        if not nums:
            return 0
        i = 0
        for j in range(1, len(nums)):
            if nums[j] != nums[i]:
                i += 1
                nums[i] = nums[j]
        return i+1

a = [1,1,2,2,3,4]
print Solution().removeDuplicates(a)
print a

[ninehills]

#4 20170803