> What if this person hacks blockchain merkle trees for breakfast, but can't be bothered to regurgitate tangential runtimes of whatever algo you decided to ask

> What if this person hacks blockchain merkle trees for breakfast, but can't be bothered to regurgitate tangential runtimes of whatever algo you decided to ask about, which they memorized and forgot 10 years ago? I've seen this to be a nontrivial intersection of skills. But most runtime derivations are pretty basic math and logic. You don't need to memorize a runtime of some algorithm, because if you understand the algorithm and what runtime analysis is about, you can derive it (in an informal hand-wavy way, at least) on the spot on the whiteboard. I wouldn't expect a rigorous derivation of the master theorem during an interview, but being able to reason a bit about worst-case scenarios and the iteration bounds of nested loops or a tree traversal seems like a pretty fundamental skill if you're discussing algorithmic problems.