# LeetCode 283. Move Zeroes

## The Problem

Link to original problem on Leetcode.

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.

## My Solution

This $O(n)$ time solution uses two variables, `i`

and `j`

, in a `for`

loop. The first, `i`

, is used to actually count iterations and stop before hitting the array’s length. The second, `j`

, keeps track of which index in the constantly mutating `nums`

array you’re currently looking at.

Every time `nums[j]`

is a `0`

, it gets `splice`

d out and `push`

ed to the end. Everything that was after `nums[j]`

will shift ahead by `1`

index value, so `j`

is decremented by `1`

to make sure we’re look at what came after that `0`

instead of what was two places after it. After `i`

iterations, we can safely assume we’ve checked the entire `nums`

array.

```
const moveZeroes = nums => {
for (let i = 0, j = 0; i < nums.length; i++, j++) {
if (nums[j] === 0) {
nums.push(nums.splice(j, 1));
j--;
}
}
};
```