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Airbnb·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Jun 2026

Summary

Airbnb software engineering interview with a fairly domain-specific coding problem around availability and date ranges. The problem felt deceptively simple at first glance but the edge cases piled up fast.

Questions Asked (1)

Q1

Design and implement an API endpoint that suggests 'split stays': given a set of named listings each with a list of available day-numbers, and a target date range [start, end], return all pairs (X, Y) where there exists some split day d such that listing X is available for every day from start through d, and listing Y is available for every day from d+1 through end.

API & IntegrationsAlgorithms & Data StructuresSystem Design
Author's notes

The example they gave made it look easy.

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AI HintsAI Generated

Suggested Approach

Clarify the problem constraints and edge cases, then propose an efficient algorithm that precomputes availability intervals for each listing to avoid redundant checks. Design the API endpoint with clear input/output schemas, and discuss scalability, error handling, and testing.

Pro tip: Mention that you would precompute prefix and suffix availability arrays for each listing to achieve O(n) time per listing, and highlight the importance of handling edge cases like empty results or invalid date ranges.

1. Clarify requirements and constraints

Ask about input size, date range limits, whether listings can be reused, and expected output format. Confirm edge cases like no available listings or split day at boundaries.

2. Design the algorithm

For each listing, compute the longest prefix of consecutive available days from start and the longest suffix ending at end. Then for each possible split day d, find listings available for [start, d] and [d+1, end] and form pairs.

3. Define API contract

Specify the endpoint (e.g., POST /split-stays), request body with listings and date range, and response with list of pairs. Include status codes and error responses.

4. Discuss scalability and optimizations

Address time/space complexity, potential for caching, and how to handle large datasets. Mention using efficient data structures like hash maps for quick lookups.

5. Outline testing and edge cases

List unit tests for normal cases, boundary splits, no availability, and invalid inputs. Suggest integration tests for the API endpoint.

Key Points to Mention

  • Precomputing prefix and suffix availability arrays for each listing to avoid O(n^2) checks.
  • Handling the split day correctly: listing X covers [start, d], listing Y covers [d+1, end].
  • Ensuring the API is idempotent and uses appropriate HTTP methods (e.g., POST for complex queries).
  • Considering performance implications for large numbers of listings and long date ranges.
  • Validating input: start <= end, non-empty listings, valid day numbers.
  • Returning results in a consistent format, possibly sorted or deduplicated.

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