The core functions weren't too bad to sketch out.
Start by clarifying requirements and scale, then design the data model and API contracts. Discuss how to efficiently handle votes and sorting, considering data structures and storage options. Finally, address scalability, consistency, and potential optimizations.
Pro tip: Demonstrate awareness of Amazon's leadership principles by emphasizing customer obsession (e.g., low-latency playlist retrieval) and ownership (e.g., handling edge cases like duplicate votes).
Ask about scale (number of playlists, guides, votes), read/write ratio, consistency needs, and whether votes can be changed or retracted.
Define entities: Playlist, Guide, User, and Vote. Decide on storage (e.g., relational vs. NoSQL) and how to represent relationships and vote counts.
Specify addGuide, vote, and getPlaylist signatures. For vote, consider idempotency and updating aggregate counts. For getPlaylist, outline sorting by votes desc and timestamp asc.
Discuss indexing, caching, sharding, and asynchronous processing. Consider how to handle hot playlists and high write throughput.
Cover duplicate votes, vote changes, tie-breaking, and consistency vs. availability. Mention monitoring and failure recovery.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
I said something about pulling the sorting logic out and using method overrides, which felt right directionally but vague.
Start by clarifying the current implementation and requirements, then propose a design that decouples sorting from the core playlist retrieval logic. Discuss trade-offs between different approaches (e.g., strategy pattern vs. comparator injection) and emphasize extensibility, maintainability, and performance.
Pro tip: Mention Amazon's leadership principles like 'Customer Obsession' and 'Invent and Simplify' by tying sorting strategies to customer needs and avoiding over-engineering. Also, highlight the importance of backward compatibility and incremental rollout.
Ask questions to understand the existing getPlaylist implementation, expected sorting criteria, and non-functional requirements like performance and scalability. Confirm whether sorting should be client-driven or server-driven.
Determine where sorting logic can be abstracted, such as introducing a SortStrategy interface or using a Comparator. Ensure the core playlist retrieval remains unchanged.
Present multiple approaches (e.g., Strategy pattern, Factory, or configuration-driven) and compare them in terms of flexibility, complexity, and performance. Recommend one based on trade-offs.
Discuss how to integrate the chosen design: dependency injection, configuration management, and API changes (e.g., adding a sort parameter). Consider caching and pagination implications.
Outline unit and integration tests for each strategy, and propose a phased rollout with feature flags to mitigate risks. Mention monitoring and metrics to track usage and performance.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.