Airtel Interview Experience for SDE (On-Campus)

Online Assessment: Three sections conducted on AMCAT.

1. Aptitude: 16 questions.
2. Technical: 14 questions.
3. Coding: 2 questions.
   • Variation of frequency sort I was happy to see this question but I couldn’t solve it completely because the platform AMCAT uses an old version of C++. Things like map, unordered_map, priority_queue, auto keyword, etc. don’t work here. Awesome explanation
   • It was a question to maximize something. I don’t remember it right now. Solved it using maxHeap. Surprisingly, priority_queue worked here :-).

I didn’t expect to shortlist as I didn’t solve the first question completely but I did get along with 45 students.

Round 1: Tech (DSA, OS, DBMS, OOPs, SQL) (1 hour 10 mins) (Interviewer: Friendly)

1. Tell me about yourself.
2. What are a compiler and interpreter? Also, state the difference between them.
3. What is a BST?
4. What are DFS and BFS traversals in graphs? After answering, further questions on the examples and working I had given.
5. Indexing in DBMS.
6. Collisions in HashMaps. What are they? How to handle them and what do we do to handle them?
7. DeadLock. Necessary conditions for a deadlock. How to avoid deadlock? (In this she wanted to know about deadlock prevention and its ways; not about deadlock avoidance and bankers ago.)
8. What is abstraction?
9. ACID properties.
10. Given a set of elements print them in ascending order. (Gave all the approaches starting from brute force till fully optimized. Also suggested that if the elements were from 1 to n, then it can be optimized further using swap sort).
11. Find GCD of two numbers.
12. CAP theorem. (Didn’t know. Said that I don’t know distributed systems; it’s gonna be taught in our course in the coming semester).
13. Given two tables Employees(ID, Name, Address, Salary, etc.) and Dependents(ID, Name, Age, etc.) where Dependents are the dependents of different employees. There is no relationship between the tables.

• Print the employees with more than two dependents.
• Prints the employees with more than two dependents along with the dependents also.
• Firstly I said that we will establish a relation between the two tables by creating an attribute with EID in Dependents which will be a foreign key referencing the Employees table.
• After this, I wrote both queries using an inner join. She was satisfied. There were more questions that I don’t remember right now. I didn’t answer a few things and felt that I won’t qualify for the next round. But I got. During the interview; after a few definitions, I immediately shared my screen and opened a whiteboard. Explained each question with examples and applications on the whiteboard.

This helped me in 3 ways:-

• I was able to answer more efficiently and able to convey everything that was going on in my head.
• The interviewer could also understand everything easily.
• It shows the interviewer that you are putting in your efforts to explain properly (V.IMP). This helps more in cases when you are stuck with a DSA question but you try hard to explain your approaches on the whiteboard.

I feel that this whiteboard method played a key role for me to qualify :-).

Round 2: Tech (30 Mins) (DSA, Puzzle) (Interviewer: Friendly)

• How was your day?
• Pascal’s Triangle
• I knew how to solve this question. Firstly, I suggested a brute force solution of making a 2D matrix and returning the kth row of the matrix ( T(n): O(n^2), S(n): O(n^2)).
• The interviewer said me okay we will look for space optimization later, you pseudocode the approach of what you just said.
• I coded it quickly and he properly Dries run the code checking out if there were any edge cases missing. He was satisfied with the solution.
• Next, I was expecting him to ask for time and space optimization but he moved over to the next question.
• 3 ants and triangle
• I got a bit nervous when he asked about this puzzle because I haven’t read any puzzles prior. I thought for some time and found an analogy between this and the coin-flipping question which asks for probability for different outcomes of heads and tails.
• I said this analogy to the interviewer and he said I was right.
• Gradually I solved the puzzle comparing it with the coin flip question and said that there were only two possibilities when the ants won’t collide.
• The interviewer was quite happy at the end.
• He said that we see how a candidate thinks and if he can backtrack to the solution rather than finding all the outcomes when the ants collide.
• The interviewer said that he is done with his interview and if I had any questions for him.
• I asked him what he works at airtel and about any project/product on which he has recently worked on.
• I didn’t feel the need of opening a whiteboard and showing every step in this round as time was less. It got over in 25 mins.

PS: This was quite a random round for everyone. Some were asked about projects and other stuff too. However, puzzles were common for everyone.

Round 3: HR (15 mins) (Interviewer: Very Friendly)

• The interviewer introduced himself.
• How was your day?
• So, where are you right now? I said I am at my home in Saudi Arabia as my college hasn’t opened yet.
• Just as I mentioned Saudi Arabia, he asked me about the country and then there was a complete background check of where I had been brought up, where I am from in India, about my parents, etc.
• Tell me something that’s not mentioned in your resume.
• We have seen that people who have been brought up in outside countries go abroad later. Do you have any plans for that? Here you need to give him a convincing answer why you won’t leave them later.
• Do you have any further education plans? Here also you need to give him a convincing answer with proper reasoning that you don’t have any plans.
• What are your expectations from this company?
• After my answering, he told me about the work culture at airtel and what they look for in their employees. Goals of airtel, criteria for measuring their employee’s performance, etc.
• There were a few more general questions in between too.
• The HR round I feel can get you trapped if you are not careful and subsequently lead to rejection. So always try to play safe and keep your stories ready for this round!

Finally, 12 students got the offer including me.

Tips:

• At last, I want to say that always be confident and most importantly calm in front of the interviewer. Whenever he/she asks a question, discuss the problem and your approach first before jumping to coding. Don’t be in a hurry, think properly before telling it to the interviewer. Even if your interview didn’t go well, don’t get disheartened.
• I have seen cases when people tell everything right and get rejected and those who made mistakes or didn’t answer are selected. The fact is you don’t know what the interviewer really wants? Still, try to give your best. Luck does matter; I feel luck plays a key role in the whole placement process. Forget what people say, I have experienced it myself.
• Have faith in your preparation, one day everything will align for you and you are gonna get there!!

Best Of Luck!