> In reality it's more often than not a role-playing exercise where you are pretending to be coworkers trying to solve problems together. Sure you'd be the one leading the problem solving, but being capable to explain your thought process effectively, having the ability to exchange ideas with the interviewer, and just being able to come across as a good teammate is probably more important than getting that last 5% of optimization.

Agreed. A lot of times the interviewer will give you hints in the right direction without holding it against you. They usually want you to succeed.