Status: New grad, M.tech from Tier-1 Institute
Previous work-ex : 1-year
Date: August, 2022

Compensation Details : - https://leetcode.com/discuss/compensation/2663759/oracle-mts-server-technology-bangalore-new-grad-2022

Note - This is going to be a detailed interview experience (I prepared it for my juniors), read it if you have enough time.

Oracle On-campus Placement Process-

1. Online Assessment - The total time given for OA was 90 mins which was more than enough for assessment. The OA includes 4 sections.

• 1 Coding problem - (difficulty- easy-medium)
  Problem- Consider two arrays a and b where each consists of n integers. In one operation:
  Select two indices i and j (0 <= i,j < n)
  Swap integers a[i] and b[j]
  This operation can be performed at most k times. Find the maximum number of distinct elements that can be achieved in array a after at most k operations.

• 1 REST API problem- Problems are only related to GET requests. We do not need to design any REST APIs, the task is to just call the GET request, fetch the data, perform some calculations and return the results.
  Suggestion- Do some practice questions related to REST api on hackerrank.
  https://www.hackerrank.com/skills-verification/rest_api_intermediate
  My recommendation is to write code in Python because it is simple to implement; otherwise, you can use any programming language (Java, javascript) that you are comfortable with.

• 1 SQL problem- problem was related to joins and group by clause with some aggregate functions.
  Suggestion: Use Leetcode and Hackerrank to practise SQL questions. Hackerrank has a more structured collection of SQL problems.

• Remaining 6-8 questions were MCQs based on data structures and aptitude.

2. Technical Interview - 1 (DSA oriented) (45-mins)

1. First question was to make me comfortable, he asked how my day had gone so far and how the pre-placement talk went. Do you find anything exciting in Oracle?

2. After that the interviewer introduced himself. Also asked me to introduce myself and open the hackerrank link that he has shared with me.

3. 1st coding problem - You are given a string ‘s’, return true or false if there exists any permutation of the given string ‘s’ which is palindrome.
   I discussed brute-force way to generate all permutations of the string and check if it is a palindrome or not. Next I discussed the approach using hashmap. Solved the problem and dry run test cases that were given by him.
   As I have used Hashmap in previous questions, he asked some questions related to hashmap. Why have you used unordered_map? What is the difference between map and unordered_map? How are they internally implemented? What is chaining and linear probing?

4. 2nd coding problem - Given a singly linked list and a pointer of any node, Delete that node from singly linked list. Is it possible to delete the last node from the singly linked list?

5. 3rd coding problem - Find the starting node of the cycle in a singly linked list.

Solved all three problems and tested it on the hackerrank editor.

3. Technical Interview - 2 (Project discussion based + DSA + Behavioural) (1 hour 10 mins)- a kind of unstructured interview

1. How was the last interview and are you able to code all the problems?

2. Tell me about yourself and what are the interesting things you have done in your academics and corporate life? I just told how I worked in my previous organisation, how I managed the challenges that I have faced while learning the new technology(Mendix). I discussed that I was part of the first team who worked on the mendix platform and discussed the projects in which I have worked in my prior organisation.

3. How do you compare academic life vs corporate life? and why are you pursuing masters?
   What are the subjects you like most and why?

4. You have used sockets in your project, are you aware of socket programming?
   I told him what the sockets are and what are the alternatives available for real time communication.

5. Have you used any of the concepts DBMS, algorithms, OOPS in your projects, discuss it with examples. I started discussing my project. Told him the reason behind building this project, what is the need and what problem it is solving. Discussed about tech-stack used.

   • I have used firebase as a backend as a service so he asked the reason behind choosing the NoSQL database. Some discussion about relational vs NoSQL database.
     He asked me about firebase authentication. How does the JWT token work? Any alternative approaches for authentication? I discussed session authentication and JWT based authentication mechanisms.
   • In my project I have implemented a debt-simplification algorithm, so the next discussion goes around it. I discussed multiple approaches to solve the problem and discussed the most optimal one by giving examples and writing on the paint. I used a heap data structure to solve the debt-simplification problem. So he asked me to explain about min-heap and max-heap.
   • Again I explained all the push, pop, heapify operations on max-heap on the paint. After that he asked me to implement the max-heap quickly because time remaining is quite less.
   • I started coding the question and implemented it partially. Then he interrupted me and moved to the next question.

6. Next question was on linkedlist, given a sorted linked list, insert a node at its correct position.

4. Technical Interview - 3* (Database design + OOPs concepts) (50 mins)*
I was thinking that this will be the HR or Managerial round but the questions that were asked were a mix of behavioural and technical questions. Interviewer was very senior, having 20 years of experience at Oracle and currently he was Director of Engineering in some vertical.

1. He asked me to first tell me the names of previous interviewers and what were the questions they have asked? He was just checking whether I was conscious or not during the interview. I was able to recall only the first interviewer's name because I sent the connection request to him an hour ago on linkedin.
2. Why do you want to work at oracle? There will be more companies visiting your campus, you can join any of them. I told him about my previous work experience and compared their work with oracle.
3. He shared a hackerrank link in which a problem was pasted on the editor, he asked to read it and explain how I can approach it. The statement was-

A university conducted a competition where students from different colleges participated. The categories were Drawing, Singing, Debate, Science Fair and SpellBee. Students participated in one or more categories and were scored out of 100. Write a query that returns the 1st, 2nd, and 3rd place finishers in each category in that order. The columns to show are category, studentid, name, collegename, and score order by category (ascending) and collegename (ascending).

• I explained the relationships between tables, need of each table, foriegn key and primary key relationships and discussed why this database design follows 3NF.
• After that I wrote the SELECT statement in which again I forgot to use the LIMIT keyword. He gave me hints that I am missing something but I told that it looks correct to me because I was quite exhausted after going through all these rounds.
• Next he asked about some OOPs concepts. He asked have you ever worked on use case, class, sequence and component diagrams. Why they are important explain it one by one. Fortunately I studied these topics in my 2nd semester of mtech, so I told him by giving some examples.
• At last he asked me if I had any questions, as the interviewer had 20 years of experience so I asked him about his journey at oracle, what are the different roles and verticals in which he worked.
  Most of the vertical names I was not able to understand because most of the terms I have heard for the first time.

I left the meeting after this round and joined the waiting room. I assumed there would be one HR round, as is standard in most interview processes. The HR representative told me to leave the meeting because no further interviews were scheduled for me. I had just left the meeting and assumed that I had been rejected because no HR round was scheduled for me. I also confirmed with other candidates, and this was the final round.

After 4 hours, results were declared and a total of 5 candidates were selected from mtech and I was one of them.

Key Points-

• Consistency is the key to success. I practiced around 800+ DSA problems consistently in the past 1-year on leetcode, binarysearch, codeforces. Although the questions asked during interview were quite easy.
• Resume should be diversified and justifiable.
• Core subjects knowledge is also necessary along with their practical usage.
• Go through the online assessment process for each company and find out previous questions asked. Oracle has changed the OA process from this year onwards and included 1 coding, 1 api related problem, 1 SQL and some MCQs. Earlier only mcq based OA was there. I extremely recommend to please be aware about the most recent interview process of any company.