[throwawaymath]

That has not been my experience as an interviewee. Implementing the naive solution for small n has been well received in my interviews, and from there (imperfectly) optimizing it is a collaborative experience.

I don't doubt you've experienced differently. But if you have, I think it's likely the interviewer, not the question. Lots of interview questions can be abused, not just basic algorithms and data structures questions.