Meta E4 London Interview Experience

I had my E4 interview at Meta in London. The process started with a behavioral round, where I answered standard questions with follow-ups, ensuring to provide real-life examples.

My first coding round featured two problems. The first was on 'Closest BST Value'. I discussed various questions related to BSTs, then presented an optimal approach for this specific problem and successfully coded it. The second question, 'Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit', was completely unexpected. I hadn't seen it before, and it wasn't among the top 100 tagged problems. I proposed a two-pointer approach, explained it thoroughly, wrote the code, and dry-ran it. I even asked the interviewer twice if they were satisfied, and they confirmed yes. However, after the interview, I realized the optimal solution involves two deques, making me question why the interviewer didn't guide me, especially since we finished 5 minutes early. This particular question left me feeling quite discouraged, given Meta's high expectations.

The second coding round also had two questions. For 'Kth Largest Element', I initially presented a brute-force approach and then optimized it using a min-heap. The interviewer then asked a follow-up on how the approach would change for frequent reads with an in-memory array. The second question was 'Peak Element'. I started with a brute-force idea and then moved to the binary search approach, struggling a bit with the explanation. I coded the optimal solution, but there was a minor bug in my conditions, which the interviewer subtly hinted at during a follow-up.

My System Design round is scheduled for next week, so the overall process is still ongoing. The challenge with the second question in the first coding round has certainly made me reflect.