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Whatnot·Software Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say
May 2026

Summary

Whatnot software engineer interview with four coding questions back to back, each requiring a walkthrough of the approach before writing any code. The pace was brutal and I was using Java which did not help. Ended with bugs in my output and no time to clean anything up.

Questions Asked (4)

Q1

Coding problem 1: implement a solution and walk through your approach before writing any code.

Algorithms & Data Structures
Author's notes

They wanted to hear the plan before any code went down.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem, constraints, and edge cases with the interviewer, then outline a high-level algorithm and its complexity before writing any code. Walk through a concrete example to validate your approach, and only then implement the solution cleanly, explaining each step as you go.

Pro tip: Verbalize your thought process continuously, including trade-offs between different approaches, to demonstrate strong communication and problem-solving skills. If you get stuck, don't panic—ask clarifying questions or propose a brute-force solution first, then optimize.

1. Understand and Clarify

Restate the problem in your own words, ask clarifying questions about input/output, constraints, and edge cases. Confirm assumptions with the interviewer before proceeding.

2. Explore Approaches

Brainstorm multiple solutions, from brute force to optimized, and discuss their time and space complexities. Choose the best approach based on constraints and explain your reasoning.

3. Walk Through an Example

Pick a representative example (including edge cases) and manually step through your chosen algorithm to verify correctness and catch any logical flaws.

4. Implement Code

Write clean, modular code with meaningful variable names, explaining each part as you write. Handle edge cases and avoid premature optimization.

5. Test and Review

Test your code with the example and additional edge cases, debug if necessary, and discuss potential improvements or alternative solutions.

Key Points to Mention

  • Clarify input/output format, constraints, and edge cases (e.g., empty input, large data, duplicates).
  • Discuss time and space complexity trade-offs between different approaches.
  • Use a concrete example to validate the algorithm before coding.
  • Write clean, readable code with meaningful names and modular structure.
  • Test the solution with normal and edge cases, and explain how you would debug.
  • Communicate your thought process clearly and ask for feedback if needed.

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

Q2

Coding problem 2: second in a series of four questions, same format of discuss then implement.

Algorithms & Data Structures
Author's notes

By the second question I was already feeling the clock.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem constraints and edge cases, then discuss a brute-force solution before optimizing with appropriate data structures or algorithms. Verbally walk through your thought process, and once you have a clear plan, implement it cleanly with meaningful variable names and test with examples.

Pro tip: Since this is the second in a series, the interviewer may expect you to build on the first problem or reuse code. Explicitly mention any connections to the previous question and ask if you should extend your previous solution.

1. Clarify the problem

Ask questions to understand input/output formats, constraints, edge cases, and expected time/space complexity. Confirm any assumptions with the interviewer.

2. Discuss approaches

Propose a brute-force solution first, then analyze its complexity and suggest optimizations using appropriate data structures or algorithms. Compare trade-offs.

3. Outline the algorithm

Write pseudocode or step-by-step logic to ensure the interviewer follows your plan. Get their buy-in before coding.

4. Implement the solution

Write clean, modular code with clear variable names. Handle edge cases and avoid off-by-one errors. Comment on key steps.

5. Test and verify

Walk through test cases including normal, edge, and large inputs. Check for correctness and complexity. Discuss potential improvements if time permits.

Key Points to Mention

  • Time and space complexity analysis for each approach
  • Edge cases such as empty input, single element, duplicates, or large values
  • Choice of data structures (e.g., hash maps, heaps, trees) and why they are optimal
  • Modularity and code readability for maintainability
  • Testing strategy including unit tests and manual walkthroughs
  • Connection to previous problem in the series, if applicable

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

Q3

Coding problem 3: third question in the sequence.

Algorithms & Data Structures
Author's notes

Blanked a bit here.

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AI HintsAI Generated

Suggested Approach

Clarify the problem statement, constraints, and edge cases before diving into a solution. Discuss a brute-force approach first, then optimize using appropriate data structures and algorithms, analyzing time and space complexity. Write clean, modular code and test with examples.

Pro tip: Communicate your thought process continuously and show enthusiasm for solving the problem; interviewers value clear reasoning and collaboration over silent coding.

1. Understand the Problem

Ask clarifying questions to confirm input/output formats, constraints, and edge cases. Restate the problem in your own words to ensure alignment.

2. Explore Approaches

Brainstorm multiple solutions, starting with a brute-force method. Discuss trade-offs and identify the optimal approach based on time and space complexity.

3. Implement the Solution

Write clean, well-structured code with meaningful variable names. Explain your logic as you code and handle edge cases explicitly.

4. Test and Debug

Walk through your code with sample inputs, including edge cases. If bugs are found, debug systematically and explain your fixes.

5. Analyze Complexity

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

Key Points to Mention

  • Clarify constraints and edge cases before coding
  • Start with a brute-force solution and then optimize
  • Use appropriate data structures (e.g., hash maps, heaps, trees) based on problem requirements
  • Analyze time and space complexity of the final solution
  • Write modular and readable code with meaningful names
  • Test with examples and edge cases to ensure correctness

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

Q4

Coding problem 4 with a follow-up: extend your solution to handle negative numbers in the input data.

Algorithms & Data StructuresTechnical Trade-offs
Author's notes

The negative numbers follow-up is what killed me.

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AI HintsAI Generated

Suggested Approach

First, clarify the original problem and your initial solution, then systematically analyze how negative numbers break assumptions (e.g., ordering, zero handling, overflow). Adapt the algorithm by adjusting comparisons, initial values, or data structures, and validate with edge cases like all negatives, mixed signs, and zeros.

Pro tip: Proactively discuss trade-offs between modifying the existing algorithm versus using a more general approach (e.g., prefix sums with a hash map for subarray problems), and mention potential pitfalls like integer overflow when negating values.

1. Clarify the original problem and solution

Restate the problem and explain your initial approach, highlighting any assumptions that rely on non-negative inputs.

2. Identify where negatives break the solution

Pinpoint specific steps (e.g., sorting, two-pointer, greedy choices) that fail with negative numbers and explain why.

3. Adapt the algorithm

Modify the approach to handle negatives, such as changing initial values, using absolute values, or switching to a more robust technique.

4. Test with edge cases

Walk through examples with all negatives, mixed signs, zeros, and extreme values to ensure correctness.

5. Analyze complexity and trade-offs

Discuss time/space complexity of the extended solution and compare with alternatives, noting any performance or readability trade-offs.

Key Points to Mention

  • Assumptions in the original solution that fail with negative numbers
  • Specific modifications needed (e.g., initializing max to -infinity, using prefix sums with hash map)
  • Edge cases: all negatives, zeros, mixed signs, integer overflow
  • Time and space complexity of the extended solution
  • Alternative approaches and their trade-offs
  • Testing strategy to validate correctness

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