Went through every round of the interview:

• Recruiter screen
• Technical screen
• Second technical screen
• Virtual onsite (3 hours): two technical, two behavioral
• Final interview with Head of Department (30 minutes)

I was led to believe I'd get an offer after the final interview, but did not.

I pressed repeatedly for critical feedback, and all I received was that "head count" was the issue.

The interview process overall was fine. I felt that the interviews were better than most companies'. Some interviewers seemed miserable and didn't want to be there, but others were very enthusiastic and helpful. One even let me use documentation for an API I'd never used.

However, to waste approximately 5 hours (plus countless hours studying) interviewing for a company I was stoked about, only to be rejected for no apparent reason, is extremely frustrating.

Additionally, the second recruiter I interfaced with throughout the process was extremely terse and always seemed as if he just wanted to get off the call.

Don't get your hopes up.

Questions are less contrived than standard technical questions.

They're based on "real" Nuro problems but simplified and condensed.

Study your algs/DS and Big O.

One of the interviews involved more low-level stuff like multiprocessing, threads, locks, etc.