Move zeros to the front
Company: Uber
Role: Data Scientist
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Technical Screen
You are given an integer array `nums`. Reorder the array in place so that all `0` values are moved to the beginning of the array, while preserving the relative order of all non-zero elements.
Requirements:
- The transformation must be done in place.
- Use only `O(1)` extra space.
- The relative order of non-zero elements must remain unchanged.
Example:
- Input: `[4, 0, 5, 0, 3]`
- Output: `[0, 0, 4, 5, 3]`
Quick Answer: This question evaluates array manipulation and in-place algorithm competencies, including handling space-time trade-offs and preserving relative order (stability) while operating with O(1) extra space.
Move all zeros to the beginning while preserving the relative order of non-zero values.
Examples
Input: ([4, 0, 5, 0, 3],)
Expected Output: [0, 0, 4, 5, 3]
Explanation: Prompt example.
Input: ([0, 0, 1],)
Expected Output: [0, 0, 1]
Explanation: Zeros already at front.
Input: ([1, 2, 3],)
Expected Output: [1, 2, 3]
Explanation: No zeros.
Input: ([],)
Expected Output: []
Explanation: Empty array.
Hints
- Fill non-zero values from right to left, then fill the prefix with zeros.