I got a Google Foobar challenge back in 2022. Never ended up completing more than the first level, but would be interesting to know if they're still using it for hiring.
The last problem on mine was really interesting, took me days. I wonder if there's a list of the problems somewhere, I thought I remember hearing that they weren't all the same.
I never did continue with the recruiting part of it, just had some fun.
The last level for me was to write a function that evaluated
sum([floor(i*sqrt(2)) for i in range(1,n+1)])It was quite detrimental to work performance though. Never heard from a recruiter, but I guess they don't employ developers in Norway.