Move zeros
Input
nums = [0, 1, 0, 3, 12]
Output
[1, 3, 12, 0, 0]
All non-zero elements keep their relative order and zeros are moved to the end.
Full lesson preview
Move Zeros Using Extra Space
Reorder an array so that all zeros appear at the end while keeping the relative order of the non-zero elements.
Python practice13 minArrays – Fundamentals & PatternsIntermediateLast updated March 25, 2026
Problem statement
Given an array nums, move all 0's to the end while maintaining the relative order of the non-zero elements. The function should return the new array (it may modify the input or create a new one). Aim for O(n) time and O(1) extra space (excluding output).
Task
Implement an in-place (or output-creating) algorithm that compacts non-zero elements to the front and appends zeros to the end in O(n) time and O(1) extra space.
Examples
Input format
Function input: move_zeros(nums) where nums is a list of integers.
Output format
Return a list of integers with zeros moved to the end and relative order preserved for non-zero elements.
Constraints
0 <= len(nums) <= 10^5. -10^9 <= nums[i] <= 10^9. Use O(n) time and O(1) extra space where possible.
Samples
Sample 1
Input
nums = [1, 2, 3]
Output
[1, 2, 3]
No zeros to move; output equals input.