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LeetCode 283 Move Zeros - Easy

283. Move Zeroes

·1 min read·#LeetCode#Easy#Python

283. Move Zeros — Easy

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Problem

  1. Move Zeroes Easy

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:

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

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

Solution

### 无法保证minimize的普通解， 机遇swap。
class Solution:
    """
    @param nums: an integer array
    @return: nothing
    """
    def moveZeroes(self, nums):
        left, right = 0, 0
        while right < len(nums):
            if nums[right] != 0:
                nums[left], nums[right] = nums[right], nums[left]
                left += 1
            right += 1
            
 
### 保证minimize的最优解， 不着急swap，先赋值，最后直接改。
class Solution:
    def moveZeroes(self, nums):
        """
        Do not return anything, modify nums in-place instead.
        """
        ### minimize the write operations:
        ### EX:
        ### 1 0 2 3 0
        ### L
        ### R
        ### 1 0 2 3 0
        ###   L
        ###   R(nums[R] == 0, skip)
        ### 1 0 2 3 0
        ###   L
        ###     R(nums[R] != 0, change  L, L += 1)
        ### 1 2 2 3 0
        ###     L
        ###       R(nums[R] != 0, change  L, L += 1)
        ### 1 2 3 3 0
        ###       L
        ###         R(nums[R] == 0, skip, end of loop)
        ### 1 2 3 3 0
        ###       L (L is not zero, change to 0, L += 1)
        ### 1 2 3 0 0
        ###         L (end)
        # write your code here
        left, right = 0, 0
        while right < len(nums):
            if nums[right] != 0:
                if left != right:
                    nums[left] = nums[right]
                left += 1
            right += 1
            
        while left < len(nums):
            if nums[left] != 0:
                nums[left] = 0
            left += 1

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