[leetcode:python]26.Remove Duplicates from Sorted Array

题目：

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.

题意：

给定一个有序数组，移除重复的元素，返回新的长度

不要分配额外空间给新的数组，空间复杂度为O（1）

方法一：性能82ms

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

方法二：性能75ms

class Solution(object):
def removeDuplicates(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
if len(nums) == 0:
return None
current = nums[0]
same = 0
for index in range(1, len(nums)):
if nums[index] == current:
same += 1
else:
nums[index-same] = nums[index]
current = nums[index]

return len(nums)-same