My IITD interview was scheduled on 24 May, 2018. I have made up my mind to not join IITB and join IITD(due to location preference). I was setting my foot inside an IIT for the first time in my life. The first shock came when I entered the college gate. I asked the guard where is **** hostel. As I was on foot he started smiling and politely replied beta wo hostel to 2 kilometer door hai. Then I remembered that this is not NIT srinagar(My B tech college). It is one of the most prestigious IITs. How naive of me to underestimate its campus area. While I was thinking all this an auto came from inside the campus. The guard stop that auto and asked him to take me to the hostel. I reached the hostel and told the receptionist that I have come for M tech interview. I was asked to pay Rs800 for two day day boarding and mess facility usage. I was then allotted a room. I met some other candidates and spent the whole day roaming here and there.

On the day of interview first there was a briefing in which Professor Sarangi gave us details about the interview process. Points from the briefing:

*A candidate has to score at least 7 points out of 10 in the interview to be even considered for M tech programme.**A candidate has to score at least 9 points out of 10 in the interview to be considered for MSR programme.**Weightage given to GATE score would be 70 percent. 30 percent weightage would be given to interview.**Even if only 10 candidates qualify the interview, IITD would proceed with only those 10 candidates. No compromise on quality and no waiting list.*

After this we were asked to sit inside a waiting room. My turn came in the very last. I entered the interview room to find 3 people sitting there. I greeted them and they asked me to take a seat. After this the 1st person asked the following questions:

- What is quicksort?
- Can you find the kth largest element in an array using the approach taken by quicksort?
- Write the code for that algorithm?
- A rectangular grid was drawn and I have to find the number of paths from one corner to another?
- Write code for printing all paths in question 4?
- Find the recurrence relation for the recursive solution that I wrote for Question 5?

I was able to answer all questions completely except question 3 where the professor confused me and then I got stuck.

The first professor was satisfied. After this the 2nd professor asked

- Give the mathematical proof for If a number is divisible by 3 then the sum of digits must me divisible by 3 ?

I said I don’t know and then he asked the 3rd professor to ask questions?

- He explained a processor (which can have infinite number of cores) and then told about a program where the sequential part is 20 percent and rest is parallel. He then asked to find the minimum number of cores required to achieve 10 times speed up?( A tricky one)
- My answer to first question made him happy. He made some changes to the above question and asked me to solve the question. I don’t remember that question now. This was the last question of the interview.

**Result: selected for M Tech but joined IITB.**