[oytis]

What a team I worked in did, is we reminded the interviewee what a binary tree is. It's a pretty simple concept, much simpler than most businesses, so it makes a good test for basic general logical thinking skills.

We were hiring for a C++ role though. I can imagine people used to higher level languages might find the very need to deal with pointers confusing

[throwaway2037]

Pointer vs reference: What's the difference? Practically, not much. All "higher level" languages (that I know ... er... except Perl) use references instead of pointers.

    > I can imagine people used to higher level languages might find the very need to deal with pointers confusing

I'm confused by this remark. What do you mean? Is this meant to be condescending? What do you use pointers for in your C++ project that references cannot do in a higher level language?

[oytis]

My point is that in higher-level languages you might spend your entire career not thinking about how your data is laid out and what points to what, while in C++ you are exposed to this reality daily even if you are working on trivial problems.

That is my hypothesis on why some people might consider inverting a binary tree an unrealistically complex problem. If you are not able to solve this problem without thinking too much you are probably not being able to write working C++ at all, but might still be able to even solve real business issues with, say, Javascript.