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Whatnot·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Did a coding round for a Software Engineer role at Whatnot. First question was a LeetCode problem involving encoded numbers, solved it pretty fast and moved on.

Questions Asked (1)

Q1

Solve a number encoding/decoding problem (standard LeetCode style).

Algorithms & Data Structures
Author's notes

Recognized it immediately and just coded it up.

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AI HintsAI Generated

Suggested Approach

First, clarify the encoding/decoding rules and constraints with the interviewer, then discuss a few possible approaches (e.g., mapping, base conversion, or state machine) and their trade-offs. Choose the most efficient one, outline the algorithm, and then implement it with clean code, testing edge cases.

Pro tip: Before coding, walk through a small example to confirm your understanding and catch off-by-one errors. Also, mention how you would handle invalid inputs or edge cases, as this shows attention to detail and production readiness.

1. Clarify the problem

Ask questions to understand the encoding/decoding rules, input/output formats, constraints, and edge cases. Confirm whether the encoding is reversible and if there are any restrictions.

2. Explore approaches

Brainstorm possible algorithms (e.g., hash map, base conversion, two-pointer, recursion) and analyze their time and space complexity. Discuss trade-offs with the interviewer.

3. Design the algorithm

Select the best approach and outline the steps in plain English or pseudocode. Consider how to handle edge cases and ensure correctness.

4. Implement and test

Write clean, modular code with meaningful variable names. Test with normal cases, edge cases, and invalid inputs. Debug as needed.

5. Analyze and optimize

State the time and space complexity of your solution. Discuss potential optimizations or alternative approaches if time permits.

Key Points to Mention

  • Time and space complexity analysis of the chosen approach
  • Handling of edge cases such as empty input, invalid characters, or overflow
  • Choice of data structures (e.g., hash map for mapping, array for base conversion)
  • Modularity and readability of code (e.g., separate encode and decode functions)
  • Testing strategy including unit tests and walkthrough examples
  • Potential follow-up questions or extensions (e.g., streaming data, large inputs)

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