My Favorite Seat!

Solving the queue-based seat-assignment problem in linear time

This hard C++ coding problem tests whether you can simulate a queue-based process efficiently without naive repeated iteration. It's the kind of problem quant firms pose to distinguish candidates who understand data structure trade-offs from those who brute-force their way to time-limit exceeded.

The core challenge is that a straightforward simulation—dequeuing, checking occupancy, and re-enqueueing on conflict—can degrade to O(n²) or worse when many people compete for the same seats. The constraint demands O(n) time complexity, which means you must avoid redundant lookups and recognize patterns in how seat preferences evolve. Key insights include tracking which seats are occupied, managing the queue state efficiently, and possibly observing how each person's preferred seat advances when conflicts occur.

• Queue data structures and circular buffers
• Set membership testing and occupancy tracking
• Identifying when to advance a preference vs. when to defer processing
• Proving worst-case bounds under conflict scenarios