Airbnb
6 questions · Coding · System design · Behavioral
Count the number of islands in a 2D grid of land and water.
CodingApproachFlood-fill each unvisited land cell with BFS/DFS and mark visited; count how many fills you start.
They look forGraph traversal on a grid, visited-state management, and complexity analysis.
Find two numbers in an array that sum to a target and return their indices.
CodingApproachOne pass with a hash map of value → index; for each x, check whether target − x was already seen.
They look forWhether you move from the brute-force O(n²) to a clean O(n) hash-map solution and reason about edge cases.
Design a social news feed.
System designApproachDiscuss fan-out on write vs. read, ranking, pagination, and the celebrity/hot-key problem.
They look forHandling scale skew and picking the right fan-out strategy.
Design a booking/availability system for listings.
System designApproachPrevent double-booking (locking/reservations), calendar storage, and search over availability.
They look forConcurrency correctness and real-world modeling.
Tell me about a time you disagreed with a teammate or manager.
BehavioralApproachUse STAR: the situation, your reasoning, how you disagreed respectfully and reached a decision, and the result.
They look forCommunication, judgment, and whether you can disagree-and-commit without drama.
Describe a project you are most proud of and your specific contribution.
BehavioralApproachAnchor to measurable impact; be crisp about what YOU did vs. the team, and the trade-offs you made.
They look forOwnership, impact, and honest self-attribution.
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