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Bloomberg·Software Engineer·Onsite - System Design / Architecture·Intermediate

Intermediate
Apr 2026

Summary

Bloomberg system design round for a software engineer role, focused entirely on designing an object-oriented Wordle clone. Pretty deep dive for a single question, they wanted class hierarchies, edge case handling, and extensibility all in one go.

Questions Asked (1)

Q1

Design an object-oriented Wordle game. Include classes for the word source, game state, guess validation, and feedback computation. Handle duplicate letters correctly and discuss how you'd extend the design for different word lengths, daily word mode, multiplayer, and hard mode.

System DesignTechnical Trade-offsData Modeling
Author's notes

This took me longer to get into than I expected.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints, then outline the core classes and their responsibilities. Focus on the duplicate-letter feedback algorithm and discuss extensibility for the mentioned features, emphasizing trade-offs.

Pro tip: Demonstrate test-driven development by walking through edge cases like 'SPEED' vs 'ERASE' to validate your duplicate-letter logic. This shows attention to detail and robustness.

1. Clarify Requirements

Ask about word length, allowed guesses, feedback rules, and any specific extensions. Confirm assumptions to scope the design.

2. Define Core Classes

Identify classes: WordSource (provides words), GameState (tracks guesses, remaining attempts), GuessValidator (checks validity), FeedbackCalculator (computes feedback). Define interfaces and responsibilities.

3. Design Feedback Algorithm

Explain the two-pass approach: first mark exact matches, then handle remaining letters with a frequency map to correctly handle duplicates.

4. Discuss Extensibility

Address each extension: different word lengths (parameterize), daily word mode (deterministic word selection), multiplayer (separate game sessions), hard mode (additional validation rules).

5. Summarize Trade-offs

Highlight design choices like immutability, separation of concerns, and potential performance considerations.

Key Points to Mention

  • Two-pass algorithm for duplicate letters: first pass marks exact matches, second pass uses a frequency map for remaining letters.
  • Separation of concerns: WordSource, GameState, GuessValidator, FeedbackCalculator as distinct classes with clear interfaces.
  • Extensibility: parameterize word length, use strategy pattern for word selection (daily vs random), session management for multiplayer, and decorator or rule engine for hard mode.
  • Immutability and thread-safety considerations for multiplayer or concurrent games.
  • Testing strategy: unit tests for feedback logic with edge cases like duplicate letters and all-correct guesses.
  • Trade-offs: simplicity vs flexibility, performance of feedback computation, and potential for caching.

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