Move Zeroes

Given an array, move all 0s to the end while keeping the relative order of the non-zero elements. Print the resulting array, space-separated.

Example

Input: 0 1 0 3 12 Output: 1 3 12 0 0

Approach

A "write" pointer tracks where the next non-zero element should go. Scan once, moving every non-zero element to the write position, then fill the remainder with zeroes.