Seen this one floating around online before the interview, which helped.
Start by clarifying requirements such as scale, access control, and operations needed. Then propose a data model for folders and files, discuss trade-offs of different representations, and outline how to handle common operations like listing, moving, and deleting. Finally, address scalability and consistency concerns.
Pro tip: Mention that you would use a closure table or materialized path for efficient subtree queries, and discuss how to handle concurrent moves to avoid cycles. This shows depth beyond basic adjacency lists.
Ask about scale (number of folders/files, users), access patterns (read vs write heavy), permissions, and operations (create, move, delete, list). This ensures the design meets actual needs.
Compare adjacency list, materialized path, nested set, and closure table. Recommend one based on requirements, explaining trade-offs in query performance and update complexity.
Define tables/collections for folders and files, including parent references and path fields. Describe how to implement key operations like listing a folder's contents, moving a subtree, and deleting recursively.
Discuss indexing, caching, and handling large subtrees. Cover concurrency control for moves (e.g., preventing cycles) and consistency across distributed systems if applicable.
Recap the chosen approach, highlight its strengths and weaknesses, and suggest potential optimizations or alternatives for future scaling.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.