Consisted of 2 coding questions and 20 MCQ’S:
Given a source and destination in a NxN maze find the shortest path between them, some of the cells are occupied and one cannot find path through them.
Second question was:
Given d, a, b and an array of integers. You can add/subtract a and b to d any number of times. You have to find the count of array elements which can be formed by applying these operations to d.
I solved 1st question using bfs approach and completed MCQ’s .31 students got selected for first round out of around 150.
F2F Round 1:( around 105 mins) The interviewer asked me to tell about myself and then he started things from my resume. Since I have a developer kind of profile and some good previous internship experience, he started with projects involved during my internships, their design patterns also asked to write approach involved in them. So with all this after around 45 minutes, he took around 2-3 min break, also offered me some cookies. I thought interview got over but then he shifted towards data structure and algorithms.He asked 3 problems :
Problem 3: https://www.geeksforgeeks.org/find-the-element-that-appears-once-in-a-sorted-array/ (O(logn) approach)
I solved all the three problems and he asked me to write code for each on paper. For second question he also asked me to draw a heapfied tree for each iteration as it involves heaps and then asked basic questions on heap. In the third question, I got confused but I discussed the approach with the interviewer and then finally after taking some time solved it.
So this was my first round, basic advice is that for every question take your time and try to discuss possible approaches with your interviewer and try to make it interactive on both side.
21 students were selected for the second round.
F2F Round 2:( around 120 mins): Interview started with the basic introduction, then he also started with my resume and asked most of the things that were there in my resume in detail. He asked me about the inner mechanism of Elasticsearch in detail, Pros and cons of using NoSQL and SQL databases, why i have used a particular DB for my project, difference between monolithic & microservices and similar backend related stuff as my resume pitched me like this, it may be different if you have machine learning projects or android or anything else in your resume. Then he asked questions from DBMS like indexing. What are the advantages and disadvantages of multilevel indexing, rearrangements in multilevel indexing, B+ tree etc. He also asked why normalization for databases, it’s different forms. Then in OS, he asked about basic concepts of paging, all the scheduling algorithms and basic of semaphores. Now it comes to ds/algo part, he asked me two questions.
I told him the greedy approach and then he asked me to write the code for it.
I told him related approach, he tried me to confuse by asking some counter questions on the approach, by giving different test cases but later he asked me to write the code for it.
With all this 2nd round got over. I was not called for the 3rd round but some people also had the 3rd round. After some time results were announced 13 were selected as FTE for OYO and I was one of them.
Advice: Mention only those things in your resume which you really know very well and be prepare with possible counter questions on them because you can’t make fool of the interviewer. Be confident and take your time to understand and solve the problem and Final if it’s your day no one can stop you to grab the opportunity 🙂 .