Facebook Interview Postmortem

Amazon TTAWSSSD
Apr 20 30 Comments

So I finished a FB onsite a few days ago and I just want to share what I went through and would like to see what you people think.

It was 4 rounds with 2 being coding, 1 design and 1 behaviour. As I arrived I was surprised at how many people were there for interviews. It scared me. It didn’t help when my recruiter didn’t come get me (I was 15 mins early for HR and 30 mins early for interview time). I had to text my recruiter and ask if I was at the right place.

Either way, I started a few mins late and first round was coding. I was rushing a lot trying to finish on time. I asked bunch of clarifying questions and went over my logic. I then started coding and iterated key parts of my algorithm. Interviewer understood where I was going and provided utility methods so I can complete it. I was stuck for a min or two and I got a hint which immediately got me into the right place. I proceeded to finish the algorithm and moved onto the next round.

To my surprise, the second round was design. I was expecting another coding but whatever. It was straightforward because the interviewer asked for specific features and let me go for it. I start with the standard clarifying and draw client and sever with load balancer. I then proceeded with database and talked about trade off there. Once those are set, I started to pick off each of the feature and started showing details by sequence diagram and what tables would be stored in database. I eventually introduced a distributed cache layer to hold key data that are time sensitive. Went through all the features and got called out couple of difficulties I didn’t deal with. I thought about it and then came up with an answer. Interviewer seemed happy and said he can go all day asking questions but for all the features he asked for, we r good and finished on time.

Then it was lunch. It was rather interesting because I end up talking a lot about me then I asked about his project and end up giving him a good idea (or an idea he really liked).

Immediately after lunch, I got the behaviour round. I am pretty sure I nailed it as I used the STARRS format and interviewer was typing a lot. I always end with “did that answer your question” and one time he said “errr what about this” and I repeated that part of the story and he quickly noted and said “oh yeah” and typed away. For the last 15 mins, I got a graph problem! I freaked out a little due to how little time I had left but still approached it calmly. I went over the idea and he liked it and started coding. I was writing a DFS via stack. I was stuck forgetting that DFS simply was adding all children. I explained the idea and interviewer said “yeah that takes practice to just write down in 2 mins why don’t we try recursion”. I said oh sure and went for it. Recursion was a lot easier as I just have base case, recurse then handle logic. Quickly finishing that interview said “yup I got the idea and I think that works. I want to use the last 2 mins for you to ask me questions”. So I did and that round ended.

This last round is what I feel I screwed up. It was an okay question, one I know the trick to but never solved one before. I was tired and room was extremely small and hot (poor ventilation). I struggled a bit and decided to just use the trick I know. Interviewer seemed happy and said yeah let’s go that path. I did but keep missing small edge cases like one off errors on index, not updating index correctly in loop. Eventually with some more struggle, I sense that I was erasing too much so I pushed to get full code out. I did and he seem to understand and we moved on. He asked for test cases and I named all the ones till he’s happy (meaning stopped asking questions). Finally it was over with me asking a few questions.

So with all that said, what you all think I did?

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TOP 30 Comments
  • New / Eng ggg1
    I think you could use some Xanax.
    Apr 20 2
    • Amazon TTAWSSSD
      OP
      Sooo .... I’m too nervous?
      Apr 20
    • New / Eng ggg1
      No. To truly understand how you did, we must know the exact number of beads of sweat and the precise vector of their travel during the interview.
      Apr 20
  • Asurion rm -rf /
    This is your side of the story. Doesn’t matter.
    Go have fun with your life and get rid of your anxiety.
    Apr 20 3
    • Amazon TTAWSSSD
      OP
      Thank you .... do I seem that nervous?
      Apr 20
    • Asurion rm -rf /
      Your narrative makes me feel so. Why not wait for the result of the interview with a bit of patience rather than asking peoples’ feedback on your side of the story. That is not going to play any part in Facebook hiring you.
      Apr 20
    • Amazon TTAWSSSD
      OP
      Yeah true, I just hate waiting.
      Apr 20
  • Tesla notElonLol
    Facebook is php 💩
    Apr 20 2
    • Amazon TTAWSSSD
      OP
      Lol ..... yes I’m well aware
      Apr 20
    • Facebook / Eng SegTree
      ”Hack” not php
      Apr 20
  • Google
    tsukino

    Google

    BIO
    w
    tsukinomore
    misread as "Postmortem" then realized it's "Postmodern" (new interview art style?)
    Apr 20 1
    • Amazon TTAWSSSD
      OP
      Just typo sorry ... gonna fix it
      Apr 20
  • Uber / Eng pgd
    Hard to say. Maybe the interviewers will see this and DM you.
    Apr 20 0
  • Microsoft leetworld
    Maybe e4 but unlikely since you fumbled through the coding questions.
    Apr 20 1
    • Amazon TTAWSSSD
      OP
      Thx for the input
      Apr 20
  • Microsoft oasisred
    What’s your YOE? What language did you use for coding?
    Apr 20 1
    • Amazon TTAWSSSD
      OP
      YOE: 5.5, I just used Java
      Apr 20
  • New hqWe60
    about 350
    Apr 20 1
    • Amazon TTAWSSSD
      OP
      Umm too good to be true?
      Apr 20
  • Facebook / Eng plus_ultra
    You were too nervous. From your description it sounds like you needed a too many hints so that's bad. But remember your perspective on how the interview went is never accurate.

    Don't worry about it.
    Apr 20 0
  • Goldman Sachs ihf
    Hey I have fb onsite this week. For system design, did you come up with back of the envelope estimation? I find that part difficult due to my lack of experience. Also were coding questions directly from leetcode (fb tagged)?
    Apr 20 2
    • Bloomberg / Eng 6FLPantry
      Yes, they asked questions like "how many computers do you need for X piece based on Y users"

      Yes, ~4/6 were tagged
      Apr 20
    • Amazon TTAWSSSD
      OP
      They didn’t ask that. For leetcode I just did medium. I didn’t even pick FB tagged ones
      Apr 20
  • Facebook / Eng SegTree
    Not doing well on the last question isn’t great, but you’ll still probably go to candidate review if the first coding went well. From there, they might see if they can corroborate negative signal from the last interview with any of the other interviews. They might ask for a follow up coding if they need more signal.
    Apr 20 1
    • Amazon TTAWSSSD
      OP
      Thx for sharing
      Apr 20
  • Salesforce jFle64
    TL;DR
    Apr 20 1
  • Ironshore arch135
    Op , you got offer ?
    Jul 9 0
  • Amazon DsAf82
    If the feedback was mixed, they might bring you back onsite to repeat the rounds which were not so great. Definitely not an L5, but could swing for L4 if you go back onsite and nail another coding.
    Apr 20 0
  • New VreM84
    Helpful stuff, thx for sharing.
    Apr 20 0