[OskarS]

Anyway, looking up max heap it's trivial, no idea what my benefit would be if I knew every variation of a tree structure somebody came up with by heart.

It's not just any other tree structure. It's the tree structure that is by far the most common way of implementing a priority queue, and it's the tree structure at the heart of the algorithm "heap sort", which is not exactly obscure. It's also the tree structure that gives "the heap" its name (though modern operating systems and allocators don't use heaps for this purpose anymore). I've personally implemented heaps in a variety of languages and contexts throughout the years as part of my work.

I don't want to sound too dismissive here, but this is not some obscure data structure with only theoretical interest. It's perfectly fine to not know off the top of your head what splay trees, Fibonacci trees or skip lists are or how they work. But if you have a degree in computer science, you should know what a heap is.

[ItsMe000001]

You are not saying anything that I did not already respond to. I know trees, I know priority queues, I completely understand the data structure. What's the point of being able to assign some completely made-up and arbitrary name to it? If you think being a walking lexicon is an achievement, okay. That's spelling contest kind of "knowledge". I get it - some people really like it. Everybody is different and that is fine. Names (by themselves) mean a lot to many people. It's a low-effort signaling thing I guess. It is fine if I was ever selected against in such an interview - it would be entirely mutual. I do not believe it tests what you think it does. If you need a priority queue and don't happen to be able to come up with a good data structure on your own - or if you are too lazy to think about it - you can just google it. As long as you understand the basics of the underlying data structures - trees, arrays, lists, graphs (in general) - you easily understand the nuances of the particular variation of the base structure.