Its my time to contribute to the LeetCode community.
Exp: 19 YOE
Location: London UK
I got mail from a Facebook recruiter sometime in August and I arranged for a Phone interview in a week's time. That time I didn't know how the things work and what LeetCode was :) Once I took the LeetCode premium subscription and going through the Facebook interview guidelines I understood where I was and so postponed the interview by a month. I applied for Amazon as well just to make use of my preparation.
Phone Interview:
I have done couple of LC problems but I was not at all ready.
Facebook E5/E6: 5 mins introduction and 10 minutes basic Android questions and then 2 LC questions (1 Easy + 1 Medium) I had no idea how I solved both the problems but after 2 days the recruiter said I was going to the onsite.
Amazon Online Assessment: I got 2 problems and I was able to solve both (These two problems were from the LC list but modified). I passed online assessment and was called for a phone interview.
Amazon L6/SDEIII: 30 minutes LP and 1 problem with Trees (Not on LC) and I managed to solve it. The interviewer was very nice. I got a mail in a couple of hours that I was going to the onsite.
I arranged both the onsites after a month from the phone interviews. I understood the LC game by that time so I increased my preparation and was able to solve Easy and few Medium but no Hard problems. Plus I had to prepare on the System Design as well. Facebook have clearly said that they are going to be based on mobile apps design and no emphasis on the Backend in their system design interviews. However Amazon said that the system design interview would contain both Frontend and Backend so I had to prepare for both.
Amazon Onsite:
I have good amount of experience and worked on few challenging projects so I had lot of success/failure scenarios and hence I was confident on my LP stories. Amazon is obsessed with OOPS design and I found its a bit vague. For eg: How do you design Amazon warehouse in 30 minutes? I have no idea how someone could come up with the classes for this as the scale is too big and we would be scratching only the surface. Plus we don’t work like this in real life.
Round1: 30 minutes LP + 1 OOPS design problem. As this is OOPS design problem not sure whether I had done good or bad but the recruiter seemed satisfied.
Round2: Bar Raiser (How did I figure out? She was the only Senior manager out of the 5 people and from a different team). 30 minutes 1 LP + 1 LC Hard problem. I left out this LC Hard problem :( so I stumbled and coded something. She went on mute and simply having fun watching me struggle :) I knew that the chance with Amazon is gone since this is a Bar Raiser round.
Round3: 30 minutes + 1 System design problem: This interviewer was the same one who took my phone interview and we both had a good round again. He was very satisfied.
Round4: 60 minutes LP with the Hiring Manager: He liked me as we both worked in similar companies and we had a good discussion.
Round5: 30 minutes LP + 1 OOPS design problem: The interviewer was a bit stone faced but the round went okay and he seemed satisfied.
Overall verdict: I would say Hire except for the Bar Raiser round but I knew that round would cost me. As expected the Amazon recruiter called me after 3 days and told the same over the phone. She said I could re-apply after 6 months. End of Amazon story.
Facebook onsite:
The experience with Facebook was very different. All the interviewers were friendly and everything was as explained in their interview guidelines and no surprises.
Round1: Coding round (1 LC Hard + 1 LC Medium) I hadn't seen the LC Hard problem but somehow I was able to solve both the problems and he seemed happy.
Round2: Coding Round (1 LC Easy + 1 LC Hard) I hadn't seen the LC Hard problem so I struggled a bit and took many hints from the interviewer.
Round3: Behavioural round (+ 1 LC Easy) I killed this round. As I had previously gave Amazon onsite I had all the stories ready so I was able to provide relevant experiences for this round and I was able to solve the coding problem as well.
Round4: System design round (1 mobile app design) It went good and the interviewer seemed satisfied.
Round5: System design round (1 mobile app design) It also went good and the interviewer seemed satisfied.
I was hoping my mistakes in Round2 would be forgiven as all the other rounds went well but I was wrong. The recruiter called me after 3 days and asked for an additional coding round. It was arranged in 10 days time and this time my focus was very clear. I have done the Top 50 Facebook questions and Facebook tagged (last 6 months) questions. And this time I had done few Hard questions as well. I was doing the Facebook Mock tests almost every day.
Additional coding round: I got the same question as I got in my behavioural round and I told her I have seen this problem so she changed the problem. 1 Medium (Not in LC) and 1 Hard (Its in LC but not tagged in 6 months Facebook and it was asked only 2 times in the past 2 years so far) so my luck was not good. I did solve both the problems but the LC hard solution was not optimal.
After 3 days Facebook recruiter mailed me saying it was a close call but they are not proceeding further so my 2 months of efforts were wasted. I never had to use/refer any of these in my work (Front end development) so I won’t be able to see any difference in my day-to-day work. In fact I asked one of the Facebook Android developers and he also confirmed that this LeetCode is only for the interview preparations. Anyways I just gave a shot as I had some free time but not going to waste any more time on FANG as the pay in UK is not that much different between the FANG and other companies.