Ex Amazon here. We never asked silly puzzle questions, but asking questions about algorithmic complexity paid off when hiring strong, senior engineers.

> Much more important is to have the experience of how code complexity accumulates, and how to mitigate that

That's part of the reason. The average developer knows how to pick a popular library and throw code at it until it works. When entire teams do that you end up with endless complexity.

That's why Google and Amazon are known for [re]inventing their own solutions.