> someone who can't discover the tortoise and hare algorithm on their own probably shouldn't have a computer science degree

This sentence is simply ridiculous. Most engineers aren't able to discover this trick. I wouldn't.

The same goes for the rod cutting problem or the maximum sub-array problem (Kadane algorithm): expecting an engineer to find them, especially in an interview, is totally inane.

Of course, nobody expects engineers and scientists to have the same skills.

Then why is tortoise and the hair credited to Floyd if it’s so trivial?

Attribution in science works in mysterious ways, and I don't claim to know how it works.

In any case, I didn't say “trivial”. If you can only derive trivial things, then you shouldn't be a computer scientist.

Are you suggesting computer scientists should be able to derive non trivial results on job interviews? Really?

This amount of nontrivial, yes. Similarly, I'd expect a computer scientist to come up with a proof of correctness for either binary search or merge sort (the out of place variant) in ~30 minutes. It's not particularly difficult.

The number of incorrect binary search algorithms published in the literature over the years would indicate otherwise…

I agree that reasoning about the correctness of a binary search algorithm is an important job skill for a computer scientist. Deriving the tortoise and hare algorithm on the fly, though, is not.