Dezerv Lead Engineer Experience

Experience: 8+ years

Company: Dezerv

Role: Lead Engineer

Rounds: 4

Round-by-Round Experience

Round 1: DSA

My first problem involved range queries on a binary array. For each query, I had to count the zeroes present between 1s within the specified range.

Instead of scanning the range repeatedly, I used nearest-one information and prefix counts so I could preprocess the array and answer individual queries efficiently.

My second problem was Sort Array By Moving Items to Empty Space. I had to determine the minimum number of moves needed to arrange the items correctly while using the empty position for movement.

I explained my logic, dry-ran it on an example and then implemented the solution.

Round 2: BookMyShow LLD

For my LLD round, I had to design BookMyShow.

I identified entities such as User, Movie, Theatre, Screen, Show, Seat and Booking, and built the booking flow around them.

The more interesting discussion started when I had to handle two users trying to book the same seat at almost the same time. I explained how I would use temporary seat locking, handle payment failures and automatically release a seat when a payment wasn't completed within the allowed time.

Round 3: Uber HLD

My HLD prompt was "Design Uber"

I first narrowed down the scope and then built the design around driver location updates, nearby-driver discovery, ride matching and trip-state management.

As I scaled the system, I discussed database choices, caching and handling a very large volume of location updates.

I was also challenged on failure scenarios. Whenever I introduced another component, I had to explain why I needed it and whether I could achieve the same thing with a simpler design.

Round 4: Senior Engineering Manager

Instead of receiving another standard design problem, I had to choose one of the hardest projects I had worked on and explain it in depth.

I walked through the architecture, production issues, bottlenecks and the decisions I would change if I were designing the same system again.

One part I found particularly interesting was the discussion around infrastructure cost. I had to identify what was costing us the most and explain how I would reduce that cost without compromising reliability or performance.

I was also asked what I expected to break first if the traffic increased significantly and how I would evolve the architecture from there.

Interview Result

I received a rejection after Senior Engineering Manager round, didn't receive detailed feedback, so I can't say what specifically went against me.