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Upstart·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Upstart software engineer screen, just one coding question. Pretty straightforward stuff, nothing that'll keep you up at night.

Questions Asked (1)

Q1

Given an integer array, remove all odd numbers and return the remaining even numbers in reverse order.

Algorithms & Data Structures
Author's notes

Easier than I expected, honestly braced for something harder.

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AI HintsAI Generated

Suggested Approach

Clarify the problem constraints (e.g., input size, whether the array can be modified in-place, and expected output format) before proposing a solution. Then walk through a two-pass approach: first filter out odd numbers, then reverse the remaining evens, discussing time and space complexity. Finally, consider edge cases and potential optimizations.

Pro tip: Demonstrate awareness of production concerns by mentioning that in a real system, you'd likely use a single pass with a stack or two-pointer technique to avoid unnecessary intermediate arrays, and you'd discuss trade-offs between readability and performance.

1. Clarify requirements and constraints

Ask about input size, whether the array can be modified in-place, and the expected output format (e.g., new array vs. in-place). This shows you think about practical implications.

2. Outline a straightforward solution

Describe a two-step approach: iterate through the array to collect even numbers, then reverse the collected list. Mention time complexity O(n) and space complexity O(k) where k is the number of evens.

3. Discuss optimizations and alternatives

Propose a single-pass solution using a stack or two-pointer technique to achieve O(n) time and O(1) extra space if in-place modification is allowed. Explain the trade-offs.

4. Handle edge cases

Mention edge cases such as empty array, all odd numbers, all even numbers, and very large arrays. Explain how your solution handles them.

5. Write clean code and test

If coding is required, write modular, readable code with meaningful variable names. Walk through a small example to verify correctness.

Key Points to Mention

  • Time and space complexity analysis for each approach
  • In-place vs. out-of-place modification and its implications
  • Use of appropriate data structures (e.g., stack, two pointers)
  • Edge cases: empty array, all odds, all evens, large input
  • Readability and maintainability of code
  • Potential follow-up: how to handle streaming data or memory constraints

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