← Bytedance Interview Insights

Bytedance·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Bytedance SRE interview, coding round. Not much to report, it was pretty quick and straightforward.

Questions Asked (1)

Q1

Given an array of integers, move all zeroes to the end while maintaining the relative order of the non-zero elements.

Algorithms & Data Structures
Author's notes

Only had about 15 minutes left at this point so I just pushed through it fast.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Start by clarifying the problem constraints (e.g., in-place, stability) and then present a two-pointer solution that maintains the relative order of non-zero elements. Walk through the algorithm step-by-step, analyze its time and space complexity, and test with edge cases.

Pro tip: Mention that while a two-pointer approach is optimal for in-place modification, if stability weren't required, a simpler partition could be used; this shows you understand trade-offs. Also, discuss potential follow-ups like handling other values or streaming data.

1. Clarify requirements

Ask if the operation should be in-place, if the relative order of non-zero elements must be preserved, and if the array can be modified.

2. Propose approach

Explain the two-pointer technique: one pointer to track the position for the next non-zero element, and another to iterate through the array.

3. Walk through algorithm

Describe how to swap or shift elements: when a non-zero is found, move it to the write pointer and increment; after traversal, fill remaining positions with zeros.

4. Analyze complexity

State that the time complexity is O(n) and space complexity is O(1) for the in-place version.

5. Test edge cases

Discuss cases like all zeros, no zeros, single element, and arrays with multiple zeros to ensure correctness.

Key Points to Mention

  • Two-pointer technique for in-place modification
  • Stability: preserving relative order of non-zero elements
  • Time complexity O(n) and space complexity O(1)
  • Edge cases: all zeros, no zeros, single element
  • Alternative approaches (e.g., using extra space) and their trade-offs
  • Potential follow-up: handling other values or streaming data

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.