Being able to write algorithms is a different thing than being able to do it without any reference or documentation on the state of the art, basically from scra

Being able to write algorithms is a different thing than being able to do it without any reference or documentation on the state of the art, basically from scratch and from the top of your head, as commonly found in interview situations. The point is that as an interviewer/employer you risk not getting the information you've asked for. Someone who is able to memorize interview algorithms isn't necessarily a good fit for the role you are trying to fill. Forcing people to memorize the details of these concepts just to comply in an interview is often a waste of time for both parties. Even as a gamedev/ML guy you don't have to reinvent the wheel everyday. You have to understand what is available, judge about the pros and cons of different solutions, pick the right one and build a good system. Preferably on time.