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This Year IIT Delhi kept the same cutoff for MTech and M S students, and the Interview was conducted in two days i.e on 23rd May and 24th May,Around 200 students were called according to the list given by them,the candidates with even registration number were called on 24th May and mine one was even too, 

Pre-Interview Introduction to MCS and MSR course:

It was given by Smruti Ranjan Sarangi sir, he told us how the procedure of interview will be going, he mentioned that

"70% of the total marks assigned will be on the basis of GATE Score and remaining 30% will be on the basis of how well you perform in the interviews,since majority of you have almost same score, so interview will be a deciding factor for your admission"

"Interview scores will be given internally on the scale of 10 and to eligible you must have at least a score of 7"

"MSR will be our premier course so whoever have appeared must have the score of 9 to get eligible for MSR"

"Interview can long from 2 minutes to 20 minutes depending on the response of the student" 

"Interview will be conducted on different panels according to the alphabetic order"


My panel was examined by Prof. Rijurekha Sen mam and Prof. Parag Singla Sir.

Our conversation went on like this

Prof.1(Looking to the records of mine):So,You are in Final year right?

Me:Yes mam.

Prof.1:What is your favourite subject?

Me:Networking and Algorithms.

Prof.1: Okay, can you tell me what all problems can be faced in a LAN in data link layer?

Me:Collision and channel access related problems might be there.

Prof.1: Can you tell me how collison can be detected and solved?

Me: Explained about the increase in frequency and jamming signal.

Prof.1:Okay what is this technique called?


Prof.1:Do wireless LANs use the same?

Me: No,mam I think it uses CSMA/CA.

Prof.1:Do you want to answer some questions on probablity?

Me(shaking head to say no as I was not confident about that subject:p):No mam.

Prof.1 saying to prof. 2:"Algorithms aur networking bola tha isne to topic of interest me" (means he said he is interested in Algorithms and networking)

(Now Prof. 2 started asking the questions)

Prof.2: can you make a program to find weather the number is prime?

Me(given whiteboard and made the program like this):

boolen isprime(int n){

for(int i=2;i*i<=n;i++)


return false;

return true;



Prof.2: why did you wrote i*i?

Me:sir,since we only need to check till square root of n.

Prof.2:Can you prove it?

.....................................................Thinking for a while but couldn't answer it....................................................

Prof.2(Coming near to the blackboard and drawing crossroad)


he gave me the problem like this

  • you are given a task to find treasure that is situated in any one of the direction, and you need to devise an efficient algorithm.
  • you are currently at the centre of the crossroad.
  • all the paths are infinitely long,so you need to take that in mind, travelling in any one one direction won't work.

Me(Thinking for a while and thinking deep inside that what kind of problem is this suddenly an idea came into my mind): Sir can we perform an operation in Breadth first manner?

Prof.2:can you explain?

Me(drawing lines on the diagram like this)


if we divide the road into uniform length partitions and traverse a unit distance at the first time,in each direct and 2*unit distance at the second time and so on.....

Prof:Okay, can you find its complexity, if the treasure is at k distance from centre?

Me(On blackboard): 


Prof.2: Can you make it more efficient?

Me:(NO CLUE TILL 2-3 minutes then he gave me some hint that to increase it exponentially) and I got the catch,and now it was like

8(1+2+4+8+16+32+.....+2logk)=16*2logk =O(k)

Prof.2 :yes, this how it is solved.

I was happy that interview was good enough

Things which I noted during IITD interview:

  • you should be good enough with algorithms, to deal with problems they give.
  • even if you say CSO or Networking is your favourite subject they will ask question from algorithms so, better say algorithm from your side too.
  • they emphsize on formal mathematics proofs,so be prepared for that.
  • profs. are friendly enough so no need to get tensed.

Verdict:-Selected :) 

posted Jun 14, 2018 in Interview Experience
edited Jun 26, 2018 by


I was asked the same crossroad question in IITGn interview. It seems to be a popular one.
what is cross word question exactly