YOE: 6
Current Position: Senior Software Engineer
Interview date: January, 2021

Note: I will not reveal the actual questions. (NDA) But will try to give jest of it - try to prepare those topics from leetcode.

Introductory Call:
HR called me and informed about the whole process and what to expect from the interviewers as well as how to approach for my preparation. Super friendly and very useful resources shared as well. I asked for 1 month for preparation (Actually HR will recommend to take that time as well)

Phone Interview:
Was given 2 questions, (Similar one's)

1. Medium question - Array's
2. Medium question - Array + Hash Table
   Both were simple to solve if you had gone through more Leetcode questions

Virtual Onsite
First Round:

1. Medium/Hard question - String (I have marked both medium and hard, since it depends on people) - I felt it required some tricks/techniques to solve it. But solvable in given time.
2. Medium question - Very standard number problem - Only trick part in this question was to handle the edge case scenarios, apart from that it was manageable

Second Round:

1. Easy question - It was standard question in leet code, involving strings and interpreting them as numbers
2. Hard question - This question was backtracking as well as dynamic programming question. My mind started panicking once I figured out it as Dynamic Programming :D But I followed just simple ways of breaking into sub-problems and voila!! Could solve it.. String + Backtracking

Third Round - Design Interview:
The question was related to implementing one feature from existing FB page. The feature is known to everyone, we definitely used them. I did pretty normal in this round. Always keep in mind that System Design rounds are always subjective - But ultimately the round went well.

Note: I gave solution only using existing technologies and things we read as part of system design preparations. Just keep your justifications ready for your technology choices.

Behavioural Round:

1. How do you handle conflicts ?
2. How you faced strong criticism/feedback ?
3. What is your most treasured project ?
4. What was your moment where you commited a mistake and how you communicated to team ?

Verdict: Got selected - But I had to reject the offer since I got competitive offer from a different company. Overall very good process and keep practising lot of questions in leetcode.

Bonus:

1. Useful link to get an idea of questions : https://leetcode.com/discuss/general-discussion/675445/facebook-interview-experiences-all-combined-from-lc-till-date-07-jun-2020