Meta | E4 | London | July 2024 [Offer]

I applied on Meta's career portal in January 2024 and received a response from HR in the last week of January. I then went through several interview rounds.

Recruiter Screening

This was a ~40-minute telephonic conversation where we discussed my past work experience, tech stack, current projects, deliveries, and impact. I made sure to be well-prepared with everything I had mentioned on my resume.

After this, I qualified for the Technical Screening round.

Technical Screening

I took 1 month to prepare and scheduled this 45-minute round for the last week of February. It started with a 5-minute introduction, followed by 35 minutes of coding, and concluded with 5 minutes for Q&A.

1. The first question was Nested List Weight Sum.
2. The second was Basic Calculator II.

I successfully provided the optimized solution, dry ran it, covered test cases, and analyzed both time and space complexity for both questions within the allotted time.

I received an email a week later, confirming my qualification for the onsite rounds. I scheduled all of them for the last week of March.

Coding 1

This 45-minute round followed the same structure: 5 minutes introduction, 35 minutes coding, and 5 minutes Q&A.

1. The first question was Lowest Common Ancestor of a Binary Tree III.
2. The second was LRU Cache.

I got slightly stuck while explaining the mathematical proof of the traversal technique for the first question, but aside from that, everything else proceeded smoothly.

Verdict: Hire

Coding 2

Another 45-minute round with the standard format.

1. The first question was: Given an array of integers, return the index of one of the largest elements, chosen uniformly at random.
2. The second question was about planning a round trip between two cities with minimum flight cost. I was given two arrays, D[] for departure fees and R[] for return fees, both of equal length with indices corresponding to dates. For example, D: [10, 8, 9, 11, 7] and R: [8, 8, 10, 7, 9], the minimum cost would be D[1] + R[3] = 15.

I was able to present brute force, optimized solutions, dry runs, test cases, and complexity analysis for both questions within the given time.

Verdict: Strong Hire

System Design

This round was 45 minutes, split into 5 minutes introduction, 35 minutes design, and 5 minutes Q&A. The task was to design a component in the Facebook app to show the top k trending hashtags of the last 12 hours, with data refreshing every hour, and different weightages for hashtags from posts, likes, and comments.

I covered functional and non-functional requirements, estimates, APIs, the data model, and a high-level design diagram, along with follow-up questions. However, I wasn't able to delve into the low-level details of components, data aggregation logic, or component interactions.

Verdict: Mixed Signal

Behavioral

This 45-minute round involved standard behavioral questions, which I answered using the STAR format.

Verdict: Strong Hire

Follow-up System Design Round

In mid-April, I received an email stating that an additional system design round was required due to the mixed signal from the previous one. I scheduled this follow-up for mid-May.

The challenge was to design a multiplayer game like chess that could scale up to 1 billion concurrent players. The constraints included no public matching, only matching with friends, and the need for a matching algorithm for friends, as well as immediate ranking board updates after a win/loss.

I thoroughly covered functional and non-functional requirements, estimates, APIs, the data model, a high-level design diagram, trade-offs between NoSQL and SQL, real-time vs. non-real-time ranking boards, and deep-dived into Apache stream processing, MapReduce jobs, and scalability aspects.

Verdict: Strong Hire

I received an offer for the E4 role in the first week of June. After two weeks for team matching and another two for negotiation, I received the final offer letter in the first week of July.