[gregors]

This sounds like a perfect question for a company that's hiring engineers who want to focus on optimizing DNA storage. If that's your goal you should just put that in the hiring criteria. You'll get more candidates that know those type of algs. If your goal is know if the candidate knows about bloom filters a better question might be "What do you know about bloom filters?" Definitely seems like you'd get answer in less than 45 minutes.

I think "key/value counts" is absolutely the correct starting answer. Anything after that is optimization. In the real world optimization comes at length through research, learning, grokking, reading, benchmarking, sleeping, mulling things over. The only way to short change that is knowing about those optimizations in advance, so might as well just ask about those algs specifically.

All that being said, I think it's an enlightening question. Thank you for sharing it! You've educated me. I've been coding a loooooooong time and didn't know about bloom counting filters specifically.