leetcode_gym/_problems/moveZeros.md

layout, title, last_solved, category, leetcode_url, status

layout	title	last_solved	category	leetcode_url	status
page	Move Zeros	2020-06-02	array	https://leetcode.com/problems/move-zeroes/	Solved

Problem

{% highlight text %}

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]

{% endhighlight %}

Solution

• Use two pointers, one to keep track of last location and another to find nonZeros
• Move nonZeros to front (oveeride)
• fill the rest of the array with zeros

Override and replace the rest with zeros

{% highlight python %}

def moveZeroes(self, nums: List[int]) -> None:

lastNonZero = 0
fast = 0

# move nonZeros to front (override)
while fast<len(nums):
    
    if nums[fast]!=0:
        nums[lastNonZero] = nums[fast]
        lastNonZero+=1
    
    fast+=1

# fill up the rest of array with zeros
while lastNonZero<len(nums):
    nums[lastNonZero]=0
    lastNonZero+=1
    

print(nums, lastNonZero)

{% endhighlight %}

---

{% highlight python %}

def moveZeroes(self, nums: List[int]) -> None:

z = None
for i in range(len(nums)):
    
    if nums[i]==0 and z is None:
        z = i

    elif nums[i]!=0 and z is None:
        
        continue
        
    elif nums[i]!=0:
        
        tmp = nums[i]
        nums[i]=nums[z]
        nums[z]=tmp
    
        z+=1

{% endhighlight %}