This question has a lot of layers and I underestimated how many until I was already mid-explanation.
Clarify requirements and constraints first, then outline the API contract (endpoint, request/response schema) and the core algorithm. The algorithm should iterate over possible split points, check availability for each listing segment, and collect valid combinations while ensuring no gaps and at most one move.
Pro tip: Discuss how to handle edge cases like same-day turnover, time zones, and partial availability, and mention that you'd optimize by pre-filtering listings that cover any part of the range to reduce the search space.
Ask about date range inclusivity, time zone handling, definition of 'valid' (e.g., check-in/check-out times), and whether listings can be used more than once. Confirm that a split-stay means exactly two listings with one move.
Specify the HTTP method (POST), endpoint (e.g., /split-stays), request body (date range and listings with availability intervals), and response format (list of valid combinations with listing IDs and split date).
For each possible split date between start and end, check if there exists a listing available from start to split and another from split to end. Ensure no overlap and no gap, and that the two listings are distinct.
Pre-process listings to index availability, use efficient interval checks, and handle edge cases like same-day turnover, time zones, and empty results. Discuss time/space complexity.
Mention how to scale for many listings (e.g., using interval trees, caching), and potential extensions like supporting more than two listings or filtering by price.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.