Airbnb·Software Engineer·Technical Phone Screen·Intermediate

Intermediate

May 2026

Summary

Airbnb SWE interview with a coding problem built around their actual product, which was a nice touch. The split stay problem sounds deceptively clean until you start thinking through edge cases.

Questions Asked (1)

Implement a function that finds all valid 'split stay' combinations: given n hotels each with an unsorted list of available dates, and a requested date range [start, end], find every (A, B, s) triple where hotel A covers [start, s] and hotel B covers [s+1, end] with A != B.

Algorithms & Data StructuresTechnical Trade-offs

Author's notes

The problem is product-flavored which threw me a bit because I kept thinking about it from a UI angle instead of just treating it as a set coverage problem.

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AI HintsAI Generated

Suggested Approach

First, clarify the problem constraints and edge cases (e.g., date format, inclusivity, hotel availability). Then, propose an efficient algorithm: for each hotel, compute the maximal contiguous coverage from start and to end, then find valid split points by intersecting coverage intervals from different hotels. Finally, discuss trade-offs between time and space complexity and potential optimizations.

Pro tip: Demonstrate product thinking by relating the solution to Airbnb's business needs: split stays increase booking options and revenue, so efficiency and correctness are critical. Also, mention how you would handle large datasets with many hotels and dates.

1. Clarify requirements and constraints

Ask about date format, inclusivity of start/end, whether hotels can have overlapping availability, and if the output should be sorted or deduplicated.

2. Preprocess hotel availability

For each hotel, sort its available dates and compute the longest contiguous coverage from the start date and the longest coverage ending at the end date.

3. Find valid split points

For each hotel A, determine the furthest date s it can cover from start; then for each other hotel B, check if B covers from s+1 to end. Collect all valid (A, B, s) triples.

4. Optimize and analyze complexity

Discuss time and space complexity, and propose optimizations like using hash maps for coverage intervals or two-pointer techniques to avoid O(n^2) comparisons.

5. Test with edge cases

Walk through examples including no valid splits, single hotel, overlapping coverage, and dates at boundaries to ensure correctness.

Key Points to Mention

Date handling: parsing, sorting, and checking contiguity (e.g., using date arithmetic or converting to day numbers).
Coverage intervals: for each hotel, compute the maximal prefix coverage from start and suffix coverage to end.
Efficient matching: avoid brute-force O(n^2) by using hash maps or sorting intervals to find complementary hotels.
Edge cases: no available hotels, hotels with partial coverage, split point at start or end, and duplicate hotels.
Complexity analysis: time O(n * d log d) for sorting dates, space O(n * d) for storing availability, and potential optimizations.
Trade-offs: precomputing coverage vs. on-the-fly checking, and handling large datasets with streaming or indexing.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.