Had a 30 min zoom audio interview and was given 1 LC question, then two weeks later was notified I made it to the final round which consist of 2 one hour interview. For the first interview I was given two LC type question and solved it and for the second interview I was given just one question. All LC type question. Was given the offer about 2 weeks later. Whole process was about a month and so

I got contacted by a recruiter after my 3rd application. They set up a typical HR phone screen to talk about the job and my background. The recruiter seemed new to their job and just read straight off the job description and asked scripted questions without really introducing themselves. They didn't seem to know much about tech and couldn't answer any of my questions about the position besides what was listed on the job description. I thought it might have been an intern doing the call. I was moved to the next stage for a ~1 hour technical Hackerrank screen. The technical screen started off with very brief introductions and moved straight to coding without any behavioral questions like others on here said they received; I'm not sure if I passed the vibe check immediately so they decided to pass on the behaviorals or what.(?) I was asked 2 questions that were around LC medium. The first question I misunderstood to start (find Fibonacci sum, but I thought it was just regular Fibonacci until I was corrected) and ended up solving in O(n) time after a little fumbling. The interviewer asked if there was a faster approach, to which I said I didn't think so. I looked it up after the interview and there is an O(log(n)) solution that involves recognizing a math trick, but I doubt anybody who doesn't already know the answer going in to the interview would recognize it. I think this question was poor and doesn't have any real life application to what your average developer would ever do. The second question I recognized two possible approaches. I stated how I would do the slower O(n) brute force approach and what it's run time would be, and then proceeded to code the faster O(log(n)) binary search approach. I got the faster approach correct-ish with one mistake that I fixed after a hint from the interviewer. I wrote some test cases prior to fixing the mistake and they all passed, so in hindsight I was missing a single test case. The interviewer tried a little to guide me to recognize that I was missing the test case, but I think the stress of the interview situation and their hints being a little too vague for me to pick up on caused me to not recognize the missing test case. I was beating myself up about that when I realized it an hour after the interview had ended, but hoped they would overlook a minor mistake and give me a chance at an onsite (that's why we work in teams, right? to help catch mistakes?). Unfortunately I got a rejection email the next day. It sucks to be rejected for not having pre-hand knowledge of a problem and/or not being perfect in another problem in a 40 minute interview, but I guess it is what it is :(.