Are you referring to tortoise-hare algorithm? I refuse to believe CS freshmen regularly come up with this on their own. Maybe a few percent, everyone else is googling or relying on huge hints from the lecturer.
If you were referring to a more trivial algorithm (e.g. linear space), I think you misinterpreted what the interviewer was expecting and would not have gotten the job.
It's also worth noting -- esp if you're referring to the TH algorithm -- that CS curricula are not standardized and that there are probably dozens of "clever trick" algorithms you haven't seen and couldn't come up with on the spot (e.g. can you initialize an array in constant time?), but someone else thinks is trivial because they happened to see it in a lecture/read it online.
If you were referring to a more trivial algorithm (e.g. linear space), I think you misinterpreted what the interviewer was expecting and would not have gotten the job.
It's also worth noting -- esp if you're referring to the TH algorithm -- that CS curricula are not standardized and that there are probably dozens of "clever trick" algorithms you haven't seen and couldn't come up with on the spot (e.g. can you initialize an array in constant time?), but someone else thinks is trivial because they happened to see it in a lecture/read it online.