The cycle-handling part I got immediately, just a visited set on URLs.
Clarify the problem: each URL is a room, and we need to traverse via HTTP requests to find an exit. Use BFS or DFS with a visited set to avoid cycles, making HTTP requests to fetch room contents and extract links. Return the exit URL if found, else None.
Pro tip: Mention that you would use a queue for BFS (or stack for DFS) and a set for visited URLs, and that you would handle HTTP errors and timeouts gracefully, possibly with retries or a session object for efficiency.
Ask about the format of the room content (e.g., HTML with links), how to identify an exit (e.g., a specific marker), and whether the starting URL is guaranteed to be valid. Confirm that cycles are possible and must be handled.
Decide between BFS and DFS. BFS is often preferred for finding the shortest path to an exit, but DFS uses less memory. Either works; state your choice and rationale.
Use a queue (BFS) or stack (DFS) to manage URLs to visit, and a set to track visited URLs. For each URL, make an HTTP GET request, parse the response to extract links, and check if the current room is an exit.
Use an HTTP library (e.g., requests in Python) to fetch pages. Parse links using an HTML parser (e.g., BeautifulSoup) or regex. Handle errors (timeouts, non-200 status) by logging and skipping or retrying.
Return the exit URL as soon as it's found, or None if traversal completes without finding one. Mention potential optimizations like concurrent requests, caching, or respecting robots.txt.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
This is where it got interesting and kind of messy.
Start by clarifying the requirements and constraints, such as retry limits and backoff strategy, then outline a modular design that separates error handling from core maze logic. Explain how you would capture and store authorization keys from successful responses and inject them into subsequent requests, while ensuring thread safety and avoiding infinite loops.
Pro tip: Mention that you would use exponential backoff with jitter for 503 retries to avoid thundering herd, and that you would treat 401 as a signal to refresh credentials rather than retry immediately. Also, highlight the importance of logging and monitoring to detect patterns in failures.
Ask about retry limits, backoff strategy, and whether authorization keys are per-session or per-user. Confirm if the maze-solving function is synchronous or asynchronous.
Implement a retry mechanism with exponential backoff and a maximum retry count. Ensure that retries are idempotent and do not cause duplicate side effects.
Extract authorization keys from successful room responses and store them securely. On 401, refresh the key if possible or fail gracefully, and forward the key in subsequent requests.
Wrap the maze-solving function with a request handler that applies the retry and auth logic. Ensure that the core algorithm remains decoupled from HTTP concerns.
Write unit tests for retry and auth scenarios, and add logging/metrics to track retry counts and auth failures. Consider circuit breakers for repeated failures.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.