The core algorithm is just DFS, so I got through the implementation pretty fast.
Clarify the API contracts and edge cases first, then implement a recursive depth-first traversal that deletes children before the parent. Discuss iterative alternatives and trade-offs like stack depth, error handling, and performance.
Pro tip: Mention that you would confirm whether the delete API is idempotent and whether the children API returns files or only directories, as these details drastically affect the implementation and error handling.
Ask about the exact behavior of the children API (does it return files and directories? pagination?) and the delete API (does it delete empty directories? is it idempotent?). Also consider edge cases like empty directories, symlinks, and permission errors.
Decide between recursion and iteration. Recursion is simpler but may hit stack limits for deep directories; iteration with an explicit stack avoids that but is more complex. Discuss the trade-offs.
Write a function that, for a given path, fetches its children. For each child, if it's a directory, recursively delete it; if it's a file, delete it directly. Finally, delete the original directory (if the API supports it) or ensure it's empty.
Add error handling for API failures (e.g., network issues, permission denied). Decide whether to fail fast or continue and report errors. Consider retries for transient errors.
Discuss time complexity (O(n) where n is number of files/directories) and space complexity (O(d) for recursion depth). Mention potential optimizations like parallel deletion or batching API calls if allowed.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.