Studying a month for a job interview...well, if you need a job and have the time, it can definitely work out well in the end. The leetcode problems are kind of fun to work on once you get into them, but they are definitely of limited use.

My Facebook interview was weird also, but the people were super nice and the coding problems were fairly easy. I failed on distributed systems architecture, oddly enough, as it was an area I had no experience in for a senior hire (but I got an offer from Google the same day I was rejected from Facebook, so I didn't have much time to be sad about it).

But managers recruiting random people, just seems weird to me. If they wanted me for my specific skill set, that would be great! But if they were just looking for general hires, they must have lost a bet or something.