I was contacted by a recruiter for Ola. She was very flexible in scheduling of the interviews. Thanks to her for awesome support for scheduling the rounds.
Interviews:
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Problem Solving round: 2 DS questions easy. (It was a month ago, so forgot what the exact question was). But it was related to array and strings. Leetcode easy.
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Problem Solving second round: 2 questions. It was 15 days ago. Supposed to be of one hour. Got over in 40 mins with both questions.
- Given an array, find if the array can be sorted by reversing any single subarray of the given array.
* Ex: In [1, 2, 3, 4, 8, 7, 6, 9] we can reverse subarray from index 4 to 6 and it will be sorted.
- TwoSum: Pair of numbers which will sum up to 6 (X).
* [1, 2, 3, 4, 8, 7, 6, 0]
* [[2,4], [6,0]]
* Assumption: Positive numbers and distinct. -
System Design round: This was 3 days ago. First asked details about my current project, asked to create block diagram of various components in my current project. Later, Asked to design the seat booking system of BookMyShow.
- GetSeatsInfo - It included fetching the seats information with grid details, screen, seat categories, seats layout, color coding to show at UI. How to store these in DB? Response, Request.
- BookSeats(User u1, array of SeatsNumbers, ScreenId, TheatreId) - Manage concurrency issues, consistency issues was the main expectations here.
- System Design round went well. It was smooth discussion. We both were part of the solution building process.
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Hiring Manager round: This was next day after design round. This round went for 1.45 hours. It was most regress round. Questions were spontaneous, and he was trying to know everything I mentioned in deep. Many questions were asked checking throughout the resume such as-
- Most challenging project you worked on and what was the challenging part of it, and how?
- Tech stack you used in this project?
- Why this tech stack was chosen?
- If you have option to create this project from scratch, choose new tech stack, how would you approach and why?
- I answered Microservices of previous answer, so he asked - why?
- What will be the microservices in your current project?
- What will be tech stack for each of them?
- What are the flaws in current project?
- What are the problems with nosql db you want to switch to relational?
- If you have to do some analytics related work on the your project, then how would you approach it in terms of DB? It is given you can't use relational db for analytics queries? - I mentioned, we will need a data pipeline, he asked how would you design a data pipeline? how will it work?
- What is rabbitmq? Differences between rabbitmq and kafka. What are the components in a message queue?
- Why is message queue is needed? Any scenario where you have used this in current project?
- What is redis? Can redis be used as message queue?
- What is caching? How it helps?
- Worked with application monitoring tools any? I mentioned kibana, graphana. He asked about the same.
- How does kibana, graphana works internally? If you have to design something like that, how would you approach?
- What kinda DB will you use for kibana and graphana? and why?
- Why is Cassandra suitable here? How is it better in terms of write extensive hits?
- How are these logging tools integrated at an environment? How they get to know all these container specific details? How are the logs messages get pushed to kibana?
- What is load balancing? Why is it needed?
- What is proxy and reverse proxy?
- How does Zookeeper works?
- What is sharding? When do you need it and why?
- Some behavioural questions -
- Any conflicts with team manager and peers? how did you resolve it?
- The best feedback you received from manager in performance reviews?
- The poor feedback you recived from manager in performance reviews? How did you handle it?
- Why Ola?
- Any questions from your side?
Verdict: Selected.
Compensation: https://leetcode.com/discuss/compensation/1110629/Ola-or-SDE-2-or-Pune