Facebook (onsite)| Research Scientist, Machine Learning (Ph.D) | Seattle, Menlo Park, NYC| October 2021
Status: CS, Ph.D Student

Continuation of Facebook-Passed-or-Phone-Screening-Sept-2021 post

Hello I will try to describe the process of the onsite. I will not reveal all the details due to NDA restrictions.

In total there were 5 Rounds distributed in 2 days(3 + 2)

1. ML Design: I would say it was not a problem I would expect (was prepared for ranking and recommendations systems). Though it was a standard binary classification problem. You had to describe the process from the beginning (data collecting, feature extraction etc), to the end (deployment). I did not manage to write a lot of things on the drawing tool because we were mostly conversing, he would ask questions and I would try to answer as well as I can and maybe touch some more theoretical non trivial things.
   I have no idea how this round went.

2. Coding Round 1: Two medium LC problems, similar to problems you will see in the facebook card and top 50 facebook problems. Managed to solve both optimaly (reviewer was planning to give me one problem, but I was done in the first 3-4 minutes, so he asked me do you want to ask me questions and finish it here or you want another problem? I said lets do one more).

3. Coding Round 2: One LC medium one LC hard, was able to solve both of them optimaly again (at least in words). The second one I never managed to code it to completion, but it was impossible too because there were only 10 minutes left and it needed at least 7-8 mins of coding given you knew how to solve it. For some reason he spent almost all the time asking questions in the first problem, which I solved fast, so I was surprised that he wanted to do a second one in the time left.

4. Round 4, Behavioral: Typical behavioral round, it was a good conversation, at times weird because she would ask me things that I did not though about (cannot say I was super prepared for this round)

5. Coding Round 3: Two medium LC questions, was able to solve them time optimaly, but the second one couldnt solve space optimaly. She told me, "I see you are going to the correct direction but there is not enough time left, so aske me some questions to wrap it up".

Extra comments:
In two of the three interviews the interviewers asked me to tell them if I have seen the question before and if I have I should say it.
Turns out that I did had seen the questions and I told them.
In the first case she ended up giving me an easier question but she made it harder by requesting a more optimal way of solving. This question I had seen too and I told her again but she said it is ok(and then she put the twist, nothing crazy though)

In the second time, I said I have seen the question and she put me one I have never seen before(initially I wwas cursing myself why I was honest :P), but at the end I calmed down and managed to solve it pretty fast.

It was defintely a tough experience, with a lot of anxiety and stress in the process, everyone though was very friendly and made the interviews easy for me. I am glad I ended up getting the offer.