It's much more important to explain your thought process, work through the problem, and come up with any solution than it is to come up with the optimal solution in these interviews. I think that's what people who rail on standard coding interviews don't understand.

It's not about memorizing the answer to algorithm puzzles. In fact - if a candidate seems to know a problem by heart, that interviewer's feedback will often be discarded. It's about putting the candidate in a position where they have to think through a problem critically and seeing what trade-offs they make, what constraints they assume, and how they communicate their intent.

I have recommended hires for candidates who don't find the canonical solution many times.