[blub]

This "average of a list" is a red herring, because in practice one gets some variation of dynamic programming, trees, graphs, etc.

And for these kinds of more complex algorithms problems I would not expect most architects to be able to solve them, since they're utterly irrelevant for their jobs. Heck, a huge amount of software developers can't solve them and bitterly (and at least partly legitimately) complain about them to whoever will listen.