Optum Interview Experience (On-Campus)

Optum visited our campus for internship and full-time employment in September 2021. The minimum GPA requirement was 6.0.

Round 1: Coding

• Round 1 was a coding round on the Hackerrank platform. There were 2 problems with DBMS queries and 3 coding questions. Coding questions were mainly from arrays, strings, DP, etc. Questions were of medium difficulty and the time limit was 90 mins. The total number of candidates who appeared for this round was over a thousand students. I was able to execute all 5 questions.
• When the results came, only 21 students got shortlisted and I was one of them. The process was very tiring as there were 4 interview rounds and all happened in 1 day itself.

Round 2: Technical

This was a basic coding round. I was asked 5 easy questions and was expected to give the best possible answer.

• https://www.geeksforgeeks.org/segregate-0s-and-1s-in-an-array-by-traversing-array-once/
• For the second question, the interviewer modified the first question and said instead of a boolean array, I had an array containing elements from 1-9 and I had to sort that in the best possible way. I gave him the solution using hashing. He was satisfied.
• https://www.geeksforgeeks.org/given-an-array-a-and-a-number-x-check-for-pair-in-a-with-sum-as-x/
• https://www.geeksforgeeks.org/find-common-elements-three-sorted-arrays/
• https://www.geeksforgeeks.org/c-program-check-given-string-palindrome/

This round took over an hour. I was asked to solve these problems in the best time and space complexity. I was able to answer all of them and only 12/21 got advanced to the next round and I was one among them.

Round 3: Technical

This was another technical round and based on DSA but a bit more advance.

• First Question: I was given the problem https://www.geeksforgeeks.org/length-of-the-longest-substring-without-repeating-characters/. The interviewer said he did not want me to sit silent. Whatever I was thinking I should tell him and explain to him even if it might be wrong. I started with the brute force approach which was O(n³) after which I told him I would try to optimize it further but he just told me how will I convert it to O(n²), I tried to convert it using the sliding window problem and then we had further discussions on the code.
• Second Question: The interviewer gave me a situation and asked me to tell him which data structure or concept comes to my mind which I should use for the same. The situation was if I am on a trip with my friends and there is a chain of payment like A–>B for some amount then B–>C for some amount, etc, I had to tell the final transaction before the bill should get settled and I need to take care of the condition if A pays Rs. X to B and B pays Rs. X to C, A should directly pay Rs. X to C in order to avoid repeating transactions. I gave my answer using Linked Lists and explained him and we had a good discussion on that as well. The interviewer was satisfied with my approach at the end.

This round took around 75 mins. I was shortlisted for the next round.

Round 4: Technical

• This was a technical round that was totally based on Backend. The interviewer started off by asking me about my projects. After having a detailed discussion on my projects he asked why have I used Firebase for the backend.
• Then the difference between NoSQL and SQL database, horizontal and vertical scaling, when do I prefer to use SQL and when NoSQL, indexing in-depth, its different kinds, why do we use indexing, what are joins, its different types, and some other in-depth questions on DBMS and RDBMS. Then he gave me 2 SQL problems for each he gave me different tables and I had to write queries.
• One question was about how to print duplicate tuples of a table and the other was I had to print Max Salary of the department for which I had to use join in 3 tables.

This round took around 1 hour again and I was shortlisted for the final round.

Round 5: Technical + HR

• The interviewer was very polite and asked me where I was and asked me to give a brief introduction of myself. He then asked me to pick my best project and explain to him the use cases and what was my idea behind it, why did I choose the specific tech stack.
• After that, he gave me a problem, https://www.geeksforgeeks.org/find-possible-words-phone-digits/. It took me 10 mins to figure out the approach and around 4 attempts to give the correct recursive function. The interviewer questioned me on my code and asked me for a dry run, then he switched to core CSE concepts from there, asked me about recursion stack, asked me about classes, how do we store them, in which memory do they get stored and why, what is serialization, how is it used in classes, which classes are not serializable and why. Then he asked me what do I think of when I hear the word “Web Server”, how I reduce redundant data, what is normalization, and its different kinds. Then he gave me a simple problem. I had to make a table as per my wish and convert it to 1NF, then 2 NF, and so on to BCNF. I made a student table and converted it to 1 NF then 2NF after which the interviewer asked me the next question.
• Then he started off with a 10-15 mins HR round. He asked me about my ambitions, if I wanted to go for further studies, what do I perceive as the word “guidance”, what was my internship experience and the difficulties I faced during the internship why I wanted to join Optum and some more general questions. And in the end, I asked him a few questions and he answered them in a very friendly manner.

When results came, only 3 students got selected and I was one among them

Tips:

• Prepare DSA, DBMS, OOPS well and it’s better to have knowledge of basic concepts.
• Have good and genuine projects in your resume.
• Always ask a question or two to the interviewer at the end, it depicts your engagement and interest towards the company.