Edit: Offered, thanks everyone!
Since many people asked similar questions, I thought it'd be better if I could post answers here:
Q: How long did you prepare?
A: Overall I've been prepping for interviews for 3~ months. For facebook, I've been preparing for 1 month. I've solved Top100FB, blind75, and then top100FB 2 times after that. I was able to solve a hard question in 10 minutes, and 20~ questions in 1 day, just prior to interviews. Recruiter itself also suggests LC. About SD, I finished Grok** S** D**, Sys Design Primer, and a few youtube videos, especially Gaurav Sen's videos. (great guy)
I'd recommend being fluent on fb top100 6 months. Also, my humble advice: train yourself to deliver a code by yourself in 10 minutes, so that during interview, with all edge-case talk and test-case dryrun, it will take 15-20 minutes total. You'll have 15-20 minutes per question, and 35-40 minutes per 2 questions. Rest 5-10 minutes for a 45-min coding session is Q/A, as most of people already state here in other topics. Best of luck everyone!
Q: From India?
A: No, from EMEA.
Q: Details on system design?
A: I can't disclose the question, but I can say that don't let the fact that the question being original scare you. If you really know the concepts at gr0kking, and their use cases, you are good to go. Don't memorize, understand the concepts at gr0kking.
Q: What do they expect?
A: Don't know really. But, to my observations and research knowledge, I think Facebook wants an all-around performance: they care about speed, communication, readability, correctness and test-cases.
While prepping, speed and familiarity is what takes the most practice I think. I'd suggest 10fastfingers.com as I regularly practice in such sites for nearly 10~ years. (I type around 130 wpm)
I'll try to give back to community as much as I can regarding the boundaries. I signed an NDA and I'll honor it. Here it goes:
Coding 1: 1 easy, 1 medium. Solved both in time. Did dry runs, talked about edge cases. I delivered both in time. 1 deficit in this round: I delivered one of problems with optimal solution, other was in O(N) where an O(logN) solution was possible. Interviewer said "I'm happy" at the end, and we proceeded to Q/A for last 5 minutes.
Coding 2: 1 easy, 1 medium. Did solve both in time, did dry run tests, talked about edge cases, all good. Both was optimal solutions. Talked about life in facebook in last 10 minutes.
System Design: This was an out of ordinary system design question (You wont find it in Gr** S** Des***). I was a bit surprised initially, but I performed smoothly. After I exit the round, I checked for online solutions, I saw that I made emphasizes on correct places. I'm thinking positive about this.
Behavioral: She was a true poker face. I don't know if she was happy with my answers or not. I don't feel like I have given her a red flag, but I also don't feel I shined in this round. I've been asked 4-5 behavioral questions. No leetcode. Session was 45min on schedule, but we talked for 1 hour and 5 minutes. I don't know if this is a good sign.
Any thoughts? Do you think I'll be getting an offer? I'll also update about results.