Leetcode: Move Zeros

The Simpsons — Giphy

Move Zeroes is a leetcode challenge that prompts you to move all the zeroes in an array to the end of that array.

The Problem:

Given an array of 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:

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

Now, there are many ways of doing this algorithm, I will be displaying two different ways to approach this very challenge!

The First Approach

The Pseudocode:

we can create a pointer called j, and assign j to 0
iterate through the array with a for loop 
now --> 
if the number we encounter is not a 0
then we take j and assign that value to that non zero number, increment j to the next index up.
once that loop is complete
loop through the array again 
this time i is assigned to j during the lop 
assign i to 0 <== essentially what this is doing is filling the rest of the array with the necessary zeroes at the end.