LeetCode--283--移动0

问题描述：

给定一个数组 nums，编写一个函数将所有 0 移动到数组的末尾，同时保持非零元素的相对顺序。

示例:

输入: [0,1,0,3,12]
输出: [1,3,12,0,0]

说明:

必须在原数组上操作，不能拷贝额外的数组。
尽量减少操作次数。

方法1：检测到为0纪录0的个数，不为0时进行赋值运算nums[i - k] = nums[i]

　　　　最后将检测到的0补到nums的最后

 1 class Solution(object):
 2     def moveZeroes(self, nums):
 3         """
 4         :type nums: List[int]
 5         :rtype: void Do not return anything, modify nums in-place instead.
 6         """
 7         if len(nums) == 2:
 8             if nums[0] == 0:
 9                 nums[0],nums[1] = nums[1],nums[0]
10                 return
11             else:
12                 return
13         k = 0
14         for i in range(len(nums)):
15             if nums[i] == 0:
16                 k += 1
17             elif nums[i] != 0 :
18                 nums[i - k] = nums[i]
19         for j in range(len(nums) - k,len(nums)):
20             nums[j] = 0

方法2：每次将元素等于0的位置变成[]。

 1 class Solution(object):
 2     def moveZeroes(self, nums):
 3         """
 4         :type nums: List[int]
 5         :rtype: void Do not return anything, modify nums in-place instead.
 6         """
 7         i = 0
 8         length = len(nums)
 9         while i < len(nums):
10             while nums != [] and nums[i] == 0:
11                 nums[i:i+1] = []
12                 if i == len(nums):
13                     break
14             i += 1
15         nums += (length - len(nums))*[0]

将方法1改进:

 1 class Solution(object):
 2     def moveZeroes(self, nums):
 3         """
 4         :type nums: List[int]
 5         :rtype: void Do not return anything, modify nums in-place instead.
 6         """
 7         length = len(nums)
 8         i = 0
 9         n = 0
10         while i + n < length:
11             if nums[i] == 0:
12                 n += 1
13                 del nums[i]
14             else:
15                 i += 1
16         nums += [0]*n

2018-09-23 09:07:49