Meta Screening Round E6 Level -Accepted

I had a screening interview with Meta today for a Senior/Staff level position. I've detailed my experience here to help others, as I was extremely nervous and anxious, but found that reading others' experiences helped me a lot.

Behavioral Round
I was anxious about the behavioral questions, but they turned out to be quite straightforward.

There was no "chaff" questions like tell me about youself etc.

He went straight to the questions. It seemed they were interested in learning about one's experience with cross-team collaboration and managing high-stress projects to determine if one suits the E6 or E5 level. He didn't inquire about the complexity or scale of the work done.

Some questions were -

Describe a project where you worked across the organization/company and collaborated with other teams.
i) What was your role in the project?
ii) Did you do any technical planning or product roadmapping for it?
How did you handle any personal or team conflicts that arose?

Coding Round

https://leetcode.com/problems/moving-average-from-data-stream/description/

Before I wrote a simple solution, we talked about the data types of the input, the required precision of the average, the window size, and how to deal with errors and overflow situations.

I made an error initially but fixed it during the test case analysis.

https://leetcode.com/problems/random-pick-with-weight/description/

The question was the same as above but framed differently.

For A/B testing, we chose a random user from a userbase spread across multiple cities, with known populations for each city. For example, 5 million in New York, 7 million in San Francisco, and 8 million in Chicago. The probability of choosing any one individual is equal. We need a method that will simply give us the name of the city from which the random user should be chosen aka lives.

I first proposed a prefix sum solution with a linear search, then considered binary search.

The interviewer prompted if an O(1) solution was possible, leading to a discussion on the feasibility of storing individual city IDs in compressed format and making an array where each element shows a person.

We discussed the limitations of the solution, which included the number of people and the number of cities. If we have only one person per city, the space complexity would be enormous. He agreed and mentioned that this was why he prompted the discussion because, in practical cases, binary search on the prefix sum was the most effective solution.

I did the binary search code, and then was asked to show case solution of edge cases.

I again did a small mistake. Quickly switched to correct answer.

After Interview

The interviewer prompted me to ask any questions I had. I inquired about some recent developments and initiatives in Meta, and how they are planning to handle data collection and scalability issues, if the Meta Horizon OS, will have as number of users as Android has. (A well thought and question related to my work in current position)

This was the most engaging conversation that exceeded 15-20 minutes of interview time. He explained to me the various changes before settling on Meta Horizon OS, the culture of Meta, how the meetings operate etc.

Final Comments and Learnings

I did make errors in some simple problems, but the discussion was lively and I managed to solve/fix all the problems. So it's important to talk and discuss before doing any problem or any step. If conversation is good, interviewer helps you in fixing all rough edges, like redundancy or edge case errors.
It's good to leverage the mock interview option with Meta, it can help one understand how those 2 questions in 35-45 minutes will feel like. and the real expectations, the possible technical glitches. I could not schedule it, as you need to give the mock availability of 5 differemt days, atleast 10 working days before the scrrening (as of now). I was planning to explain the solutions and do dry-runs on whiteboard of CoderPad by opening it in iPad, but it stopped working mid-interview, and I got flustered. I think therefore and otherwise.

Thanks to this platform and other people's post for aiding in prep.

Response From Recruiter

Got a response the day after. They are moving ahead.

Coding Round - No special feedback on coding as it was good (but not exceptional), so there is room for improvement.
Behavioural Round - The behavioral round could have been more structured. The recruiter recommended preparing answers for each general behavioral question, rehearsing, and refining the storytelling.