I was asked this question when I interviewed in 2020 and finished in about 35 minutes without any C experience. I can confirm that this question made me very interested in working for MemSQL/Singlestore: I loved the experience. The next step of the interview was to implement a pretty large concurrent program. I was given conflicting/very little information from the recruiter on how to complete the assignment, which I thought was odd given that in my estimation this was far too large for an interview question. I submitted my work after a couple hours of effort in an incomplete state because I decided I didn't really want to work for the company anymore. I never heard back. Really soured me on the company.

Seconded this. I interviewed at MemSQL in 2013 as an intern, and that (plus other algo based questions) get me really hooked to MemSQL.