Facebook Software Engineer Interview Questions

Updated Oct 27, 2014
Updated Oct 27, 2014
362 Interview Reviews

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5 people found this helpful  

Software Engineer Interview

Anonymous Interview Candidate in Menlo Park, CA
Anonymous Interview Candidate in Menlo Park, CA
Application Details

I applied through an employee referral. The process took 2+ weeksinterviewed at Facebook in January 2013.

Interview Details

I was referred by a college friend. The whole precess was about 3 weeks (excluding time to get visa, Christmas and new year holidays).

Interview Details Started with a friendly talk with the recruiter, had 1 phone screen and then 4 on-site interviews + 1 lunch interview. Everyone was was very Smart and kind of friendly during the interview.

Interview Questions
  • 1- Try to solve interview question as much as you can.
    2- You may not be able to answer the question 100% correct. Don't worry, try to explain you thinking process.
    3- Talk with your interviewer like you potential team-mate in future. It would help you to communicate efficiently.
      Answer Question
Negotiation Details
They were not very open in the negotiation. That was the only down-side of my interview. I had offers slightly better than their offer. However I was convinced that FB is the best place for me. So, I accepted the offer.
Accepted Offer
Positive Experience
Difficult Interview

Other Interview Reviews for Facebook

  1. 9 people found this helpful  

    Software Engineer Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied through college or university. The process took 4+ weeksinterviewed at Facebook.

    Interview Details

    Solved their online puzzle, got contacted by campus recruiter, scheduled phone interview, went on-site for 2nd round interview.

    Interview Questions
    • Nothing unexpected, I solved all the problems but I think I was too slow on the first one, which goes like:
      Given an array of numbers, they are arranged so that the a[0] is in the 1st bucket, a[1]a[2] are in the 2nd bucket, a[3]a[4]a[5] is in the 3rd bucket and so on. The question is then: given a number, you need to return if it is in any bucket or not.
        View Answers (7)
    No Offer
    Positive Experience
    Difficult Interview
  2. 89 people found this helpful  

    Software Engineer Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied through a recruiter. The process took 3+ monthsinterviewed at Facebook in November 2013.

    Interview Details

    This was for a position in their Infrastructure team in Cambridge MA.

    Recruiter contacted me in September and was very interested in my background and experience with highly scalable systems - both in Finance and Mobile phone payments.
    I attended some small intimate presentations they did as they were initially opening a new Boston office and wanted to grow it out. The meetings were great and I learned a lot about how they solve some of their biggest problems.

    I then did a screening interview on-site (because I don't do technical screens well on the phone). The question was "Given a binary tree, write code to print the tree out line by line". I did OK and got the Breadth First Search down fine, but couldn't figure out the - line-by-line part. (Turns out this is Facebook's #1 question to ask in interviews).

    Although my performance wasn't great they gave me a break on that and asked me back for another screening interview. This time I prepared well for another coding interview but it turned out to be a Design interview. The problem was

    "Imagine you have 10,000 servers and need to monitor the performance of each one, how would you do it" - naturally you need to be able to NOT take too much of the bandwidth and so you'll have to do sampling, have some history to watch for trends etc.

    I passed that and was very excited to be flown out to Menlo Park for the final round.
    I studied like CRAZY based on questions on this site and CareerCup. I took 4 weeks and studied about 15 hours per week.

    Turns out I focused on the wrong questions - I studied Tree, String, Array and List algorithms based on the distribution of Q&A but I was asked Binary math and heap algorithms. Here are the questions I was asked.

    1) How would you implement division without +, - or multiplication (a "classic" question, but not one of the ones I would focus on). I bombed on this as I was not expecting and could not recall my binary math. I figured out the high level outline but that was all. That I was asked this in the "culture fit" interview made this doubly unexpected.

    2) Given 10,000 servers containing a Billion integers each how would you find how to find the median? I knew the answer to this question (use two heaps) - not because I had focused on it, but I had found it an interesting question while studying. However he then asked "How much memory do you need?" and I didn't know how big the heaps would need to be. The real answer I was trying to get is - what is the minimum heap you need. I had a guess but I think I got this wrong.

    3) Given a List structure where each node contains a Next node and optionally a pointer to another list, flatten that list
    e.g.

    L1 --> L2 --> L3 --> L7 --> L8
                          |
                          v
                         L4 --> L5-->L6

    WIll be flattened to
    L1 --> L2 --> L3 -->L4 -->L5-->L6-->L7-->L8

    I did OK on this - getting the answer - but it appeared I took too long. The interviewer also interrupted me a lot while I was writing an initial solution and that threw me off - I like to be more iterative in my problem solving but I think he expected 100% immediate correctness.
    He had an observer there too and that guy looked bored out of his mind and that bugged me a little too as it wasn't clear who would be doing the judging.

    4) I was also handed some hard to read Python code (I don't know Python) and asked to figure out what it does. I did OK on this - but again surprised to be handed hard-to-read code in a language I didn't know.

    5) One final question "How would you implement the "ls" Unix function in your language of choice. It should take the input:
    >ls a/b/c/*/e/*/f/*/*/g
    and the output should be similar the the output given by unix."

    I used a tree structure to represent the file directory structure and wrote a solution from there. I did OK on this.

    Overall: Everyone seemed very nice - I had a nice lunch and the campus is interesting but it was clear that what I studied was not what I needed to (so lesson learned: don't just trust the distribution of questions on Glassdoor or CareerCup). I even got to walk past Zuckerberg's office (more of a conference room) and saw Sheryl Sandberg in there.

    One interesting thing I learned is a lot of Google people are leaving for Facebook. Also I'd say if you are over 30 (I am 41) you are a rare bird at Facebook :-)

    I knew based on the reactions of the interviewers that it was very probably a bust, but overall a good experience and something I will learn from. Very disappointing as I really wanted to be one of the first few Facebook engineers in the Boston area - and to work on their super high scalability issues but such is Life.

    Interview Questions
    • How would you implement division without +, - or multiplication   View Answers (6)
    No Offer
    Positive Experience
    Difficult Interview
  3. 2 people found this helpful  

    Software Engineer Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied through other source. The process took 2+ monthsinterviewed at Facebook in December 2013.

    Interview Details

    (Front End Developer)

    After going to a conference, and talking with several people from Facebook who also attended, I was contacted via email to see if I was interested in doing an interview.

    I said yes, and got my first phone interview a few days later. In a shared code environment I needed to do a recursion assignment, and also create a polyfill. It went okay, although I wasn't happy with my performance on the polyfill. This took about 40 minutes.

    The more surprised I was that they asked me for a second phone interview, whereby I also had to do a recursion question. I made it harder then necessary for myself, which was unfortunate.

    After this I was invited to Facebook HQ, and had to do 4 interviews. Interviews were about recursion, closures, css, implementations. Unfortunately I wasn't good enough for Facebook, so that got me messed up for a month or so. I thought I did pretty good, but needed too much time to get going.

    The recruiters and interviewers were great. The process went really smooth, and comfortable.

    Interview Questions
    • Questions about recursion, css positioning, what would you like to do at Facebook, and closures.   Answer Question
    No Offer
    Positive Experience
    Difficult Interview
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  5.  

    Software Engineer Interview

    Anonymous Interview Candidate in São Paulo, São Paulo (Brazil)
    Anonymous Interview Candidate in São Paulo, São Paulo (Brazil)
    Application Details

    I applied through a recruiter. The process took 3+ monthsinterviewed at Facebook in February 2014.

    Interview Details

    The recruiter contacted me by LinkedIn and schedule a phone interview 10 days later.
    It was a high level talk about my background and my interest in Facebook.
    2 weeks laters I had a technical Skype interview with online coding.
    The day after, the recruiter sent me an email saying I did well and would be scheduling a onsite interview at their office in Sao Paulo.
    The interview took place in February, almost 2 months later.

    No Offer
    Positive Experience
    Difficult Interview
  6. 12 people found this helpful  

    Software Engineer Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied online. The process took 4+ weeksinterviewed at Facebook in August 2013.

    Interview Details

    The processes started with a very quick phone screening that went over my interests, why I wanted to work for Facebook, etc, which was followed up by one or two phone interviews in which I was asked to enter code into a browser and answer a few technical questions. They also asked a few questions about my resume. I took a flight to their on-site interview which included a gorgeous hotel and generous compensation for food, etc. The on-site interview was a few hours but it flew by. Some interviewers seemed experienced and others seemed like they didn't know what they were doing in the interview room. Everyone I interacted with (from phone screening to the actual interviews) seemed very organized and the entire interview process was extremely smooth. I greatly appreciated their coordination and team effort.

    Interview Questions
    • Most difficult questions were around systems design since the question was extremely broad, in which I was supposed to write/draw on a white board for 30-45 minutes explaining what the concept was about. Another unexpected question involved the trie data structure, it wasn't too hard, but I've never heard of it.   Answer Question
    Reasons for Declining

    I didn't want to commute from San Francisco every day and the culture seemed a bit off. Some interviewers were incredible to talk to, however others seemed very arrogant which isn't who I would want to work with.

    Declined Offer
    Positive Experience
    Difficult Interview
  7.  

    Software Engineer Interview

    Anonymous Interview Candidate
    Anonymous Interview Candidate
    Application Details

    I applied through college or university. The process took a dayinterviewed at Facebook.

    Interview Details

    First round interview, 45 mins long

    Interview Questions
    • How would you multiply two strings: "123 * "45", without any casting.   View Answers (8)
    No Offer
    Positive Experience
    Difficult Interview
  8.  

    Software Engineer Interview

    Anonymous Interview Candidate in London, England (UK)
    Anonymous Interview Candidate in London, England (UK)
    Application Details

    I applied through an employee referral. The process took 7+ weeksinterviewed at Facebook.

    Interview Details

    They were as friendly as you can imagine and gave me a T-Shirt. I met a kind of famous security guru.

    Interview Questions
    Reasons for Declining

    I'm still in the loop.

    Declined Offer
    Positive Experience
    Difficult Interview
  9. 22 people found this helpful  

    Software Engineer Interview

    Anonymous Interview Candidate
    Anonymous Interview Candidate
    Application Details

    I applied through a recruiter. The process took 2+ weeksinterviewed at Facebook in July 2012.

    Interview Details

    The process was fast and challenging. Phone interview, then remote technical interview with live coding through a web code share site. After passing those rounds I was invited to onsite interview in Menlo Park. The onsite interview involved 4 different people, with a lunch break. I am in my mid 30's in age, and I must say I felt like the old guy at the club. My interviewers were all younger than me, and had a palpable air of superiority. I felt like I nailed each of the interviews, but was not extended an offer with "You struggled on one of the interviews" as the only explanation. Its hard for me shake the thought that it was more work culture than work skill that prevented me from receiving an offer. All in all, no complaints. It was a fun and challenging experience and I ended up with a better job in the long run.

    No Offer
    Positive Experience
    Difficult Interview
  10. 4 people found this helpful  

    Software Engineer Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied through a recruiter. The process took 4 weeksinterviewed at Facebook.

    Interview Details

    Easy process. Be prepared.
    .

    Interview Questions
    • 1. Modified permutation
      2. Design news feed
      3. Modified Binary search.
      4. Sort graph points
        Answer Question
    No Offer
    Positive Experience
    Difficult Interview

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