Fizzbuzz is such an incredibly simple problem if you can’t do it I struggle to see how you’d be able to complete any task that requires very basic reasoning and very basic coding knowledge. And if an AI system can do those parts, what am I getting for spending tens of thousands of pounds per year by hiring a person who can’t? Wouldn’t I just tag codex on the tickets?

I’m not talking about gotcha level stuff here where the first time it didn’t compile because of a bracket or anything, or even first time wrong. They couldn’t do Fizzbuzz in a language of their choice, at all.

Those that could were always annoyed at having to do such things because how could someone coming for a contract position not be able to do this? Without seeing what a filter it really was.

I feel the same way about inverting a binary tree, but a lot of people act like it's an arduous request. I am guessing it's because they've never read the description of what inverting a binary tree is, but maybe people are just that bad at recursion.

You can go your entire career without recursing, or using a tree data structure in its raw form (i.e. you only use it as part of a library)

Right. For the first many decades of computing, recursion was just always the wrong answer for a production software system. (Feel free to provide a counter-example, but please begin with an explanation of how the size of a call stack frame is determined and how exceeding the base allocation is handled on this platform).

So what tree-traversal/quicksort problems tend to measure is how long it's been since you last did CS class homework problems.