Had my first FANG interview recently. Rejected after 10days.
YOE: 4 yrs in midsize company (2 of those in SWE and 2 yrs in a different domain)

Phone screen:

1. Some variation to remove invalid paranthesis- solved this one easily without trouble and was able to run through test cases.
2. Have a list of subtrees and a tree, return a boolean array with T/F to see if the subtree is in the tree or not. Was able to think brute force solution and implemented it (with some pseudo code for checking equal tree) since time was running out by that time.

Overall phone screen experience was good. Interviewer was very friendly. I didnt think that I will get a chance to move ahead. But got an email from HR that they will move ahead the very next day.

Virtual Onsite:
Round1:

1. Some complex variation of grid, to get longest path - I somehow went with dfs first and half way through realized that I should rather use bfs. Implemented it by the end of 40min :(

Round2:

1. HR round. Typical questions on challenges at previous work, how to handle conflicts.- I was able to connect with the interviewer (thats at least what I think) and I think this round went well

Round3:

1. Variation of merge intervals - solved it and ran through test cases
2. string Addition - solved it exactly by the end of 40mins
   Had a chat for 5 mins with the interviewer. I think this is one of my best rounds

Round4:
Typical System design round on a feature with Ads. There were places where the interviewer didnt seem to quite agree with what I said. Moved on to discuss other things.

Round5:
Second round of system design. Was asked about another feature about Facebook Ads. Question is open ended. Interviewer had an open mind and we had an enjoyable discussion

Round6:
By this time, my mind is drained.

1. Variation of picking elements with equal probability. I am not so sure, if my solution is optimal. But the interviwer said we will move on to second question. I couldnt read his face and there was absolute pin drop silence from his side.
2. Sorted large stream of numbers with many duplicates. Implement a frequency counter. I was able to get to the solution and almost about to finish coding, time ran out and the interviewer asked for approach. He said he understood what I was trying to do. Didnt comment on it being right/wrong.
   Interviewer seemed very experienced.

Overall, my interview 'experience' was good. I could have done better in many places. The first round is where I felt my performance was sub-optimal and probably my worst round. I was able to code up only 1 question, didnt get a chance to run through it to check for bugs.

Self-evaluation:
With only 3 months of preparation, I have come a long way. Learned a lot along the way too. Recruiter mentioned that feedback is mixed. And strong points were problem solving, weak points were speed and code verification(may be since I didnt have time for a few coding probs).

• I still need to pick up speed in coding, I need to practice and keep grinding.
• ML rounds were not perfect either according to the minimal feedback I got. I need to probably take more mock interviews to improve and need more feedback to build on.

I followed discussions on leetcode very closely and they have been a huge help to me. Hopefully my experience will help atleast a few of you.