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Apple·Software Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say
Jun 2026

Summary

Apple SWE interview with a low-level C coding problem centered on an airplane seat reservation system. Pretty involved for a single session, lots of edge cases to think through on the fly.

Questions Asked (1)

Q1

Implement a set of C functions for an airplane seat reservation system: create an airplane struct with configurable rows, seats per row, and two aisle positions; print its layout; free all allocated memory; and reserve a specific seat by name, with an optional fallback to a nearby seat if the requested one is taken.

System DesignAlgorithms & Data StructuresTechnical Trade-offs
Author's notes

This was a lot to hold in your head at once.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and edge cases, then design a clean data structure with proper memory management. Implement the functions incrementally, ensuring correctness and efficiency, and discuss trade-offs like fallback strategies and error handling.

Pro tip: Demonstrate awareness of real-world constraints: mention that seat reservation systems must handle concurrency and memory safety, and propose using a 2D array with sentinel values for aisles to simplify indexing.

1. Clarify Requirements and Constraints

Ask about expected seat naming convention, fallback proximity definition, and whether the system needs to handle concurrent reservations. Confirm memory allocation expectations and error handling.

2. Design Data Structures

Propose a struct with rows, seats per row, aisle positions, and a 2D array (or 1D flattened) of seat statuses. Consider using an enum for seat states (available, reserved, aisle).

3. Implement Core Functions

Write create_airplane, print_layout, free_airplane, and reserve_seat. For reserve_seat, parse the seat name, check availability, and if taken, search for the nearest available seat using a distance metric.

4. Handle Edge Cases and Errors

Validate inputs (e.g., invalid seat names, out-of-bounds), handle allocation failures, and ensure free_airplane releases all memory. Discuss fallback behavior when no nearby seat is available.

5. Test and Discuss Trade-offs

Walk through test cases (e.g., reserving aisle seats, full flight). Discuss time/space complexity and alternative designs like linked lists or bitsets for large airplanes.

Key Points to Mention

  • Memory management: allocate and free all dynamically allocated memory, avoid leaks.
  • Seat naming convention: e.g., row number + seat letter (e.g., 1A), and how aisles affect lettering.
  • Fallback strategy: define 'nearby' (e.g., same row, then adjacent rows) and implement search efficiently.
  • Error handling: return error codes or booleans, and handle invalid inputs gracefully.
  • Concurrency considerations: mention mutexes or atomic operations if multiple threads may reserve seats.
  • Trade-offs: simplicity vs. performance, e.g., 2D array vs. bitset, and how aisle representation affects indexing.

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