Meta E3 - Reject. All the grind down the drain.

Meta E3

Round 1

Valid Word Abbreviation Moving Average from Data Stream

Successfully completed both questions, finishing the interview in 25 minutes.

Behavioral Round

Successfully answered standard work style questions.

Round 2

Dot Product of Two Sparse Vectors Pow(x, n)

Coded both questions optimally. For the first question, I suggested a hashmap approach and then transitioned to a vector of pairs. The interviewer seemed unhappy with my initial suggestion of using a hashmap, and asked me to estimate the memory consumption of the hashmap, including the hash function, in bytes.

After completing the vector of pairs approach, the interviewer wanted me to address potential overflow issues in the dot product calculation. I suggested using 'long long', but this was not satisfactory. I then suggested modular multiplication, but this was also not satisfactory. I received no hints from the interviewer. The first problem alone took 30 minutes, and the interviewer remained focused on the overflow issue.

I had 10 minutes remaining for the second question and provided bug-free code. Based on my experience of 50+ interviews, this interviewer was among the most challenging I've encountered.

Verdict - Rejected. I am unsure what the interviewer expected in the second round.