Hash Table Collisions

What this hash table collision interview question tests

This is a medium-difficulty digital design question that probes your understanding of hash table collision strategies in a hardware context. Rather than asking about software implementations, it grounds the problem in FPGA memory constraints and real-time order-book semantics, where both correctness and latency matter.

To reason through this question, you need to evaluate common collision-resolution techniques—such as chaining, open addressing, double hashing, and cuckoo hashing—and assess which are practical when the underlying storage is block RAM (BRAM) with fixed access patterns. The question rewards candidates who can think about trade-offs between memory utilization, lookup time, and implementation complexity on silicon.

• Collision resolution strategies (chaining, probing, rehashing)
• BRAM access patterns and port limitations
• Trade-offs between deterministic latency and memory efficiency
• Order preservation and data integrity in financial systems