Applied online through their website and got an email asking me to take a Hacker Rank challenge about a week later with a semi-personalized email from a recruiter. The Hacker Rank wasn't that tricky (implement a very basic key-value database with rollback support). They gave two weeks to do the Hacker Rank, but stated the expectation was that I would finish it within 2-3 hours (which I did). A few days after I submitted, they sent denied me over email. As far as I'm aware, I met all of the stated runtime complexity requirements. I passed all of the provided test cases and I also did some manual testing to ensure correctness. So, I'm confused as to why I got rejected.

After you apply, you'll be sent an online assessment. Mine was 2 questions, both string parsing. First one passed, second one was extremely involved and I didn't finish it, but still got through to the next round. Then a recruiter will reach out via email so you can schedule a technical interview. The interview is (I believe) 60 minutes, but may have been. 45, can't remember. You log onto a shared code pad, the interviewer describes the question, you code live while talking through it on the phone. Can choose pretty much any language. Must create your own input/test cases. You have whatever time is remaining to ask questions/talk to the interviewer.