Juspay Interview Experience | On Campus 2022

This was an on-campus opportunity that was presented for 3 roles :

• SDE
• Product Engineer
• Technical Product Analyst 

ROUND 1: ONLINE CODING ROUND

• There were basically 3 questions asked on graph data structure and were quite challenging.
• One problem was easy and the rest two were medium.
• A basic understanding of graph traversal would suffice to clear this round.
• The total mark allocated was 300 out of which I scored around 170 so I qualified for the next round.

ROUND 2: HACKATHON PART A

• After a few days, I received a mail that stated that I was shortlisted for the SDE role.
• Before the round started there was an orientation meeting where we were informed about the upcoming rounds.
• This round was basically a hackathon.
• There was only one question in this round which we had to solve in 3 hours.
• It was a hard question on n-ary trees for which we had to write optimized code like the limit was at max O(log N).
• The total marks allotted for this round was 300 out of which 150 or above was mandatory to qualify for the next round.
• My score was 300 so I qualified for the next round.

ROUND 3: HACKATHON PART B

• After 3-4 days of the first part of the hackathon, I got to know that I was shortlisted for the next round.
• For this round, one whole day’s availability was required.
• This round was basically a more advanced version of the previous round where we had to optimize our code first. As mine had a few cases where it would take O(N) time the interviewer first asked me to optimize the code.
• I was able to optimize by using a few hints from the interviewer and he was satisfied as he wanted even the worst case to be O(logN).
• Later he told me to implement my code such that it would be thread safe when deployed in a multi-core machine.
• This was quite challenging as these concepts were new to me but the interviewer was generous by constantly giving hints.
• Initially, I gave a solution that would make the entire process thread safe but it was similar to executing it on a single-core machine.
• After a few more hustle I figured out a solution that was both thread-safe and optimal for the given conditions.
• To get an idea of making it thread-safe you need to have knowledge of operating systems especially process synchronization, parallelism & multi-threading.
• Later I was asked 2 DSA questions on tree and graph data structure both were easy to medium questions. Having knowledge about tree traversals and a few graph algorithms would be enough.
• This round lasted for about 6.5 hours and it was held on slack where the mentor was assigned to me.

ROUND 4 : SYSTEMS + TECHNICAL INTERVIEW

• Post part B I received a call from the recruiter that I have been selected for the next round which was the systems interview.
• This was a normal technical interview held on google meet.
• The interviewer started off with an introduction.
• Later he asked me a question about the time complexity calculation of a data structure.
• I was also asked a few operating system questions, the interviewer always expects a general answer rather than a textbook answer where he also asked me to describe clock speed to a 4-year-old so one of the answers I gave was that you could travel the entire galaxy at an instant which he was not that satisfied.
• He asked me 2 DSA questions one was a medium problem on a matrix where he concentrated more on the space and time complexities he was expecting the space to be O(1)
• The second question was based on Tree data structure it is a hard problem and a famous one that would require in-depth knowledge of traversal.
• I was able to solve both questions but the interviewer told me that there was one edge case missing in the matrix problem, but he was very much satisfied with the second code.
• He also asked me a few questions on system design which would include sharding and load balancing.
• The knowledge of multithreading, multiprocessing, semaphores, and other concepts is a must for this round.
• I was also asked a general question on how two applications would work on a single-core machine.
• Also just know how the computer works in general as they expect you to know these as a fresher.
• This round lasted for about 1.5 hours.

ROUND 5: CULTURAL FIT ROUND

• The next day post round 4 there was a cultural fit round scheduled, this was an HR round.
• The interviewer was very friendly he asked me about my family background and my childhood.
• Later on, he asked me about my project and he also asked me to scale the project.
• Lastly, he asked me about Juspay, like where have you seen it.
• Then he asked me if I had any questions so I asked him about his experience of working at Juspay.
• This round was for about 30 minutes.

FINAL VERDICT: SELECTED AS PRODUCT ENGINEER

SKILLS REQUIRED TO CRACK THE INTERVIEW PROCESS: 

• GOOD KNOWLEDGE OF DATA STRUCTURES AND ALGORITHMS (ESPECIALLY TREES AND GRAPHS)
• GOOD KNOWLEDGE OF OPERATING SYSTEMS
• SYSTEM DESIGN BASICS
• BASIC KNOWLEDGE OF DBMS, CNS, AND OOPS
• KNOWLEDGE OF HOW A COMPUTER OPERATES