[LeetCode] Challenge log 283

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283. Move Zeros

The key is to use no extra space, hence swap is most convenient. To optimize operation, only swap when encounter zeroes.

Given an array nums, write a function to move all 0‘s to the end of it while maintaining the relative order of the non-zero elements.

Example:

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Input: [0,1,0,3,12]
Output: [1,3,12,0,0]

Note:

  1. You must do this in-place without making a copy of the array.
  2. Minimize the total number of operations.
Soulution:

standard solution: 

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class Solution:
    def moveZeroes(self, nums):
        """
        :type nums: List[int]
        :rtype: void Do not return anything, modify nums in-place instead.
        """
        cur = 0
        tail = 0
        n = len(nums)
        while cur < n:
            if nums[cur] != 0:
                nums[cur], nums[tail] = nums[tail], nums[cur]
                tail += 1
            cur += 1

my solution: 

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class Solution:
    def moveZeroes(self, nums):
        """
        :type nums: List[int]
        :rtype: void Do not return anything, modify nums in-place instead.
        """
        if nums == []: return []
        n = len(nums)
        i = 0
        while i < n :
            if nums[i] == 0:
                del nums[i]
                nums.append(0)
                n -= 1
                i -= 1
            i += 1
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