They're probably referring to this tweet from Max Howell [0]
> Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so fuck off.
I personally wouldn't hold that against him (or Homebrew). We also don't really know if Google rejected him based on the binary tree, or if it was something else (personality?).
> But ultimately, should Google have hired me? Yes, absolutely yes. I am often a dick, I am often difficult, I often don’t know computer science, but. BUT. I make really good things, maybe they aren't perfect, but people really like them. Surely, surely Google could have used that.
And a sensible response from Jonathan Blow to the "binary tree" nonsense:
> I hate to say it, but counter to most replies you are getting, I see this as an expected outcome. Inverting a binary tree is not some trick interview question. It's a very basic data structure manipulation, and the ideas involved there are applicable to everything. I probably wouldn't hire someone who couldn't solve this, either. It most likely indicates lack of comfort with (or understanding of) recursion, which is kind of serious. This is not to say that the hiring process is good (I have never experienced it) or that they shouldn't have hired you (quite possibly they should have) but maybe instead of getting mad, take this as a cue that you could build up your data-structure-manipulation muscles a bit more and become better for it -- as that stuff applies everywhere.
They're probably referring to this tweet from Max Howell [0]
> Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so fuck off.
I personally wouldn't hold that against him (or Homebrew). We also don't really know if Google rejected him based on the binary tree, or if it was something else (personality?).
[0] https://x.com/mxcl/status/608682016205344768
[1] https://news.ycombinator.com/item?id=15713801