Most viewed posts in Interview Experience

GATE 2018 Rank - 453

Category - General

year of graduation -2015

stream - CSE

Here I will be talking about my IISc CSA research interview.

My date of CSA Research interview was 21' st May, 2018.

CSA M.Tech. Research interview experience

For CSA Research , we had been given a selection form where we had to fill our choices of the research area, sub areas and background subjects which we wanted to be interviewed on. My choice-

Research area - Intelligent systems

Sub areas - Machine learning, data mining

Background subjects - Probability, Linear Algebra

Before the interview, we had a short half an hour written test. The paper for written test was different for every research area group - Intelligent Systems, Theoretical Computer Science and Computer systems.

The test was moderately easy with 10 questions in total. It had 2 questions from probability, 2 questions from eigen values and characteristic equation of a matrix, 1 question to sort the given functions into increasing order of time complexity, 1 question to guess the output of a c program, 1 question from computer organization cache part(to calculate the no of bits in tag field). There were 3 more questions which I don't remember. 

My advice on written test- In the question paper itself we had rough work area below each question. Try to provide the solution of your answer neatly in that area for each question as well. This might help the interviewers to know your level of understanding. Moreover it might create a good  impression of you on them.

I could answer 7/10 questions and all were correct to my knowledge. The results of the test was quickly announced within 1 hour. I was shortlisted and we were headed towards our interview rooms. My interview panel had 3 professors.

I1: Suman, you have graduated from IIEST Shibpur in 2015 and you have a cgpa of 8.02.

Me: Yes sir.

I1:  So what did you do for these 2-3 years after graduation?

Me: Sir, I was working at Lexmark International India Pvt. Ltd as a software engineer mainly on automation.(They did not seem much interested in knowing my job profile though).

I1: So Suman, you have selected Intelligent systems as your reasearch area and selected mc learning and data mining as sub area with background subjects probability theory and linear algebra?

Me: Yes sir.

I1: So what are the topics you have prepared for linear algebra?

Me: Matrices and determinants, Eigen values.

I1: Shall we start with eigen values?

Me: Yes sir.

I1: What are eigen values and eigen vectors?

Me: Answered.

I1: If you are given a matrix of order mxn, what are the number of eigen values it will have and why?

Me: (There was a trick in this question) Sir, for a matrix A to have eigen values we should have the order of A as nxn(i.e. it should be a square matrix and determinants exists only for square matrix). When we write the characteristic equation of the matrix, it comes out be a polynomial equation of degree n, and no of roots of a polynomial equation of degree n is n. The roots of this equation will be the eigen values, hence n eigen values for an nxn matrix.

I1: What do you mean by degree of a polynomial?(At this point I understood that they dig really deep to know whether we understand the basic maths concepts or not)

Me: The highest power of x in a polynomial in terms of x.

I1: Can a matrix of order 3 have 3 eigen values, two of them real and one of them complex?

Me: No sir. Because the characteristic equation of this matrix will be a polynomial of degree n and every polynomial equation has complex roots, if any in conjugate pairs. (This was a tough question for me and I gave a wrong answer).

I1: Take an example of a diagonal matrix and write it on the board.(I wrote). The matrix looked somewhat like this - 

I1: Looking at this example can you say that it is possible to have a complex eigen value and two real eigen values?

Me: (Confused) Yes sir. (Clearly it can be seen that eigen values of this matrix are 3i,1 and 2. So I said yes. But I am still confused about this.)

I1: Lets proceed further. Given a matrix relation A2=A, can u determine what will be the value of rank(A)+ rank(A-I)?

Me:(I was completely unaware of this, still I tried to deduce something.) It can be seen that A is an idempotent matrix. With the given relation we can write- 

A(A-I)=0, which means either A=0 or A=I (which is completely wrong. By now they would have seriously started doubting me.)

I1: Okay lets proceed Suman.

Me: (I somehow remembered for the previous question that if product of 2 matrices AB=0, it is not necessary that either A or B has to be a null matrix. I quickly fixed my mistake by saying it.) Sir, I made a mistake there, it is not necessary that either one of A and A-I has to be zero.

I1: Okay.

After this I was handed over to the 2nd professor who remained quiet all this while.

I2: What are the topics you have prepared in probability?

Me: Sir conditional probability, random variables.

I2: Okay so do you know what is a CDF?

Me: No Sir.

I2: (surprised) Have you never heard of it?

Me: (At that moment I could not remember anything as I was disappointed with my performance so far) No Sir. But I know what a PDF is.

I2: What is a PDF?

Me: Sir probability density function(I could have also said probability distribution function but this is what I could remember at that time. I explained what a probability density function in detail by explaining it on board with the help of graph of a random pdf. I also explained how the integration of probabilities of all the points on x axis turns out to be 1.)

I2: Okay. Can you tell what is the pdf of an exponential random variable?

Me: (My confidence went down further because I remembered the pdfs for all other random variables except this. I still said yes in the heat of the moment)Yes sir. It is

xe-λx (This is incorrect.Correct function is, f(x)=λe-λx where x >0 and f(x)=0 otherwise)

I2: Okay. Prove how the sum of probabilities for all the points for this random variable is equal to 1.

Me: I tried by integrating this function over x from x=0 to 1.(Even though my function was incorrect I tried to follow the correct method of proving it. The interviewers helped me one or two times wherever I was stuck, still my result was not coming out to be 1 because of the incorrect function I was using. I even remembered and said the correct function for exponential random variable somewhere in the between, but the interviewer said that the function does not matter, which implied that he was more interested in the approach I was following)

I1: Okay Suman, we are done with the interview

Me: Thank you Sir

Result: Selected

Blogs of CSA Research Interview Experience at IISc.

https://stanlysamuel.quora.com/Indian-Institute-of-Science-Bangalore-interview-experience-June-8th-2016-which-made-me-an-IIScian

https://meghabyali.wordpress.com/2016/06/24/my-journey-to-iisc-2/

Hi Friends,In this post i am going to share my MS Interview Experience which was held on 15th may at IITK.

First we had to clear written and programming test,held on 14th may 2018 and common for all M.tech/MS/PHD candidates.

You can find written test and programming questions in below post.

https://gateoverflow.in/blog/4508/iit-kanpur-m-tech-test-experience-14th-may-2018

Remember,they had two categories for test Theory and system and you had to choose any one of them.

I choosed System.Questions were easy.Most of them were from CO,OS,DBMS and few from algo and C.

I done very well in both written and programming test.

In the evening we got list of shortlisted candidates for MS interview.I got shortlisted for the MS interview which was scheduled on next day 8:30AM.

Those who  applied only for MTECH were free to leave ,after programming test.

I wasn't that serious about the interview,because i heard that they have very limited seats for MS.

I woke up at 8:00 AM and rushed to the interview venue without an breakfast.

There were 50-60 candidated shortlisted for sytstem category and around 20-30 for Theory category.

My turn came at around 12 AM.

There were Three professors in Room,all of them were very polite and encouraging.

Interviewer:Tell us something about yourself.

Me:I Told about my educational background and Job.

Interviewer:What kind of work you do at job? And then some other simple questions related to job.

Me:Told.

Interviewer:Have you passed all the test cases for both programming questions?

Me: said yes.They looked impressed with that.

Interviewer:What project you did in your b.tech.Do you remember that?

Me:i said yes and told them that my project was about designing a online Kmap calculator.

Interviewer:Can you please explain that on white board.

Me:i explained them about gui part on board and also the algorithm that i used in that.

(After this i explained everything on white board till interview ends.)

Interviewer:What was the motivation for this project.

Me:Told.

Interviewer:What are your favorite subjects and why?

Me:I said CO and OS and told them i was very interested in cpu design in b.tech and designed a 8-bit cpu from using only logic gates in a simulator.

(Again they were very impressed)

Interviewer:How can you implement a given FSM into the hardware?

Me:I took some time and told them by using combinational ckt.(may be sequential but i said combinational).

Interviewer:They gave me a FSM in truth table and asked me to design combinational ckt. for it?

Me:I designed it using i/p and o/p relationship.(i used these things when designing cpu).

Interviewer:Draw block diagram for the ckt.

Me:I drawn block diagram with the all input /output connections.

(Then there were some other basic questions related to modifications that we can do in that ckt.)

Interviewer:What is your favorite part in OS?

Me:I said process management.

Interviewer:How process starts?

Me:Told them that os first bring that process or part of the process in the MM.Then scheduler select process anI draw it and explain all the inputs and o/p.d assign cpu to it?

Interviewer:How cpu know address of instructions in process?

Me:In virtual memory system ,we have page table that translate LA to PA.

Interviewer:Where page table is stored?

Me:In Main Memory.

Interviewer:Can user Process access Page table entries?

Me:No,it is done in kernel mode.

Interviewer:so,every time we cpu access MM it need to switch to kernel mode to access page table?

Me:i wasn't sure but i said yes.

Then they discussed if any other professor wants to ask any question.

But all looked satisfied.And they asked me to leave.

After coming out from interview room,i was very sure that i will be get selected.

And ,in the end i got both M.tech and MS offers from IITK.

I will be going for M.tech.

Please keep in mind that in any MS interview they have following structure

1.Job experience or b.tech project

2.Favorite subjects.(Prepare these subjects thoroughly from basics)

And also see the area where you are applying and choose subjects according to that.

I choosed os and co because i had selected system and i also got benefit of this.

 

Based on the gate score shortlisted some students and on the day of interview we were introduced about RA program, they cleared our doubts there is no difference between TA and RA program in terms of coursework and placements. There are 4 professors who introduced about their projects and what are their requirements.

Followed by a written test consisting of 16 questions (CO, OS, DS, Algorithms,Math’s mainly)

Then called for the interview, there were 8professors inside the room. It covered General subjects interview (CO, OS, DS, Algorithms,MATHS) followed by Project specific interview.

Subject’s interview

First question was tell about yourself - told

Started with CO

Professor: What is difference between Cache and TLB

Me: Cache used to store words, TLB used to store entries.

Professor: What is Temporal Locality and Spatial Locality. Given some references of pages and block size, use LRU. Will it be an advantage for Temporal Locality or Spatial Locality – Told.

Professor: Will there is an integer greater than every integer. Is true or false

Me: Told it is not a proposition

Professor: Why and what is the definition of proposition?

Me: Proposition is statement we can say true or false. Here I assumed integers are Universe set of Disclosure so we can’t give a number greater than any number and say true or false, so it is not a proposition.

Professor: If we have an array with all numbers same except one number. Tell me an algorithm to find different number.

Me: Told a algorithm and they asked me to find the time complexity for the same algorithm

Professor: Asked about basic concepts of threads – told. They have given a case study assume we have linked list and want to do basic operation (Insert, Delete, Min), want to perform parallel operation by using threads. Tell me your approach.

Me: As linked list is like a critical section we can’t perform the operations parllely as it will lead to inconsistency problem. They asked me what is Critical section.- Told. They said there exists an approach we can work parallel

. I have been thinking for some time- not getting idea.

They stopped me and we will come to that later and asked some more questions couldn’t remember. Finally they asked me to wait, there is another round of interview at afternoon 3:00.

Project specific interview:

They asked me tell me set associative cache and what is its format- told

Explained and given the format as

Tag

Set No

Offset

 

Asked me about what is miss in cache – told.

Professor: Let’s assume Tag and Set No are interchanged.

Assume offset is 2Bytes, set no is 3bits, and remaining tag. And the references are 0 to 16(each 1 Byte). Then how many no of misses.

Me: Written references on board 0000 0000

                                                                   0000 00001 …………………………………………..till 16

                                                                    0001 0000

New format is  

Set No

Tag

Offset

 

I told all the references will be mapped to the same block of cache because all the references having the same set no “000”. For every reference we are getting 2Bytes in  cache. So for every two references 1 miss. So totally 8 misses.

Professor: Satisfied with my answer. I was happy.

Professor: Came back to the Threads question parallel operation

Me: Actually thinking about same question during my lunch got some idea, told some.

They asked me to wait for another interview.

General Interview:

They asked me to tell about my self- told

What are the things you have done apart from your course work of B.Tech – told.

They asked what your interests of learning are- I said ML/AI, I just heard the terminologies, I want to learn full time under professor guidance.

Professor: project is related to ML/AI with computer architecture. – I was happy that I can learn the new things (ML/AI).

Finally completed my interview.

After 2 days Professor called me and confirmed that I didn’t applied for other IIT’s and willingness to join

On that day itself I came to know I was selected for RA before results.

Hope this post helps somebody to get interview exposure.

                                                                                               

 

1st Round Interview:

T: Introduce yourself

Me :Gave small introduction

T:subjects in which you are comfortable to answer

Me: Data structure and Algorithm

T:How to find maximum element in a Binary Search tree

Me:first i told general approach(similar to find max in array) then they sent  me to  board then i explained efficient way (logn complexity)

T:can u write pseudo code for what you explained

Me:I wrote

T:There is an integer which is greater than every integer. Is this statement  true or false?

Me:false

T:why??

Me : explained

T:write first order  logic of what you explained.

Me:$\forall x,\exists y,y>x$

T:negate the above statement

Me:done

T:what is this statement mean

Me:explained

T:why deadlock will occur here(questions from the written test)

Me:explained

They told me to wait because there may be another round of interview

After 3-4 hours ,they called me again for another round of interview

Interview Round 2(for formal method project):

T:what are the sorting algorithm you know

Me:told all 7 to 8 algorithm name which i knew

T:which algorithm you think is better

Me :answered

T:why you are saying this and why not this and few more question

Me:i replied all

T:Let G(V,E) be a graph. Let w(ei) is weight of edge i. w(e1)<w(e2)<w(e3).........<w(emax). Let T is MST of G.

 i) w(e1) ∈ T, ii)w(e2) ∈T , iii)w(e3)∈ T ,iv)w(emax) ∈ T

Me:Explained for first two case(easy one)

T:What about iii ?

Me:In somecases w(e3)∉T

T:why??

Me:Explained

T:what about iv ?

Me :In somecase w(emax) ∈ T

T:why?

Ans:Explained

T:what is the time complexity to find 3rd max element in max heap?

Me:I went to board and explain clearly (O(1) time complexity).they were looking satisfied by answer.

T:Sorted array is given .You have to find two number from array which is equal to C(given number)

Me:first i explained algorithm which takes $n^{2}$ time

T:Even if array is not sorted we can do in $n^{2}$ time .can we do in better way because we have sorted array

Me:I gave nlogn algorithm.

T:what you told is correct but can you optimise it more

Me :tried but not getting  

T:they gave hint like $a_{1}+a_{n}>c(given number)$$a_{1}(first number of array)+a_{n}(last number of array)>c(given number)$

Me:after thinking little bit i got O(n) algorithm.they satisfied by answer

T:Draw an automata for language having as many occurence of 10 as 01?

Me:I started drawing but in the mid they stopped me

T: 3 red ball(identical) and 5 green ball(identical) .no of ways we can arrange such that no two red ball are adjacent

Me:Answered

They told i am done. I was happy because i answered almost every question and feeling satisfied.

After 15-20 mins

3rd Interview(for parallel processing project):

T:why mutual exclusion will occur here(question is from written test)

Me :Explained in detail on board

T:Another question from written test regarding synchronization

Me:not able to answer but made me to think then they gave hint and at last they explain me the answer

After coming out of interview room i was very happy .

I hope this post may help at least someone who are preparing for gate 2018

My gate rank is 527 and score is 728

Hello Everyone
This post is regarding the admission procedure in IIITD.
So there are two ways to get admission in IIITD(Both exclusive, you cannot through both choices)
1)Gate entry
2)Non Gate entry
 
//if you are a gate entry then u will get stipend else u will not get any stipend(only difference b/w both  the entries)

Gate Entry:-
Screening 1:-
Requirement :- Rank <= 3000 and college percentage>= 75% (As per my knowledge, dont know the exact criteria)
(if you have good rank and low percentage and vice versa, still u can get the call)

Actually they calculate a score in which they take average of the gate score and college percentage of the candidate and if the candidate’s average crosses the cutoff then the candidate is called for further procedure.

formula=(0.5 * gate score + 0.5* college%) 
(last time the cutoff was 71 point something)

Screening 2:-
On 5 may,we were called for interview.Around 350 students were called and there were only 100 seats.

Last time there was no coding round , Only interview was there.

Non Gate Entry:-
Screening 1:-
You need not to get a good rank to get admission through this entry.Only requirement is that u should have a good college percentage.
College percentage must be above 75% (As per my knowledge,last time cut off was 75%).

Screening 2:-
For non gate entry, there were 2 tests on 5 may - first written test and then interview(only those candidates were interviewed who cleared the written test)
Last time around 150-180 students were called,and there were only 35 seats for non gate.

Interview Experience:-
So on 5 may we were called for interview, after spoiling almost every exam I was quite nervous...haha.
There were around 13-14 panels,Each panel had 1 professor and 2 PhD students.
Type of questions varies from panel to panel.Also it depends upon the field of the professor who is taking the interview,(Literally this really matters, I mean if your favourite subjects are same as the professor's field, then you will really  face some good questions, because they will make u stuck at the basic concepts but its not even that hard to crack it).

So my interviewed started from some basic questions like tell me your favourite subjects,to which i replied C,DS,Algo,OS
then the first question was which algorithm would you choose to sort the playing cards and why?
Then they asked about semaphores,mutual exclusion and many more...(ps:- I seriously dont remember any question now)
But i was able to answer all of them correctly.
At the end they asked about my project, but since i was not so confident about my project,So i directly said that i am not too confident in my project as i am in btech 4th year and working on it(Since i wanted to play safe, because i knew  that if they asked about my project ,i will lose the opportunity to get admission)
The professor was okay with it,and he just asked about my project topic only and then i came out of the room.

After  3-4 days, results were announced and i was selected.

About non gate entry exam:-
First u need to solve a written test, difficulty level is moderate, it consists of both aptitude and gate subject questions.
Once u clear it, u have to pass the interview and the interview procedure is same as that of gate entry.
Non gate results were also announced after 3-4 days.

ps:-(i mentioned everything as per my knowledge, dont know the exact criteria)
How i prepared for  interview:-
I just revised my notes thats it.

One simple note:-
I prepared whole heartedly for gate, studied as much as i could, but could not get a good rank in gate.
After that i spoiled other exams too like IIITH and many more.
On the interview day,I was really depressed and nervous and at the time of my interview , i got so nervous that the professor offered me water bottle and said first drink water and then answer...hahahahah.
See, we all work hard , we all want to go to IIT Bombay, but sometimes we do not perform well by any reason but u know what "mehnat kabhi bekar ni jaati", If u could not perform well in one exam, u will perform well in another and if u spoiled that too,then u will perform well in the next one.

1 thing that i will suggest to everyone that "Dont Give Up till the end, keep fighting", sometimes student dont get admission not because they didnt have a good rank but just because they gave up too early and they start thinking of dropping 1 year.
I would suggest dont even think of dropping until all the doors are closed.

I hope this post will help others.
Sorry for all the grammatical mistakes.
this is my first post btw...
and trust me after getting admission in a good college u will realize that "Gate preparation was halwa,khoon to ye log choos rahe h"...hahah (Atleast in IIITD u will definitely realize it).
bcoz IIITD is a world full of Deadlines...hahaha. 

IITB-RA (Projects list and General Process)
Cutoff - 750 (GATE score)

There is a 2 step process to select candidates. The main point to note is your GATE rank doesn't matter in the whole process. Rank is only used for shortlisting.

Written test - It consists of GATE level questions and shouldn’t be a problem if you have prepared well for GATE. For CS the question paper was of 30 marks and roughly divided in 3 parts- Systems, Algorithms and Maths/aptitude.
Programming test- A basic programming test for 2 hours, the point to be noted is that marks of programming test are not considered for all RA positions.
Interview - After written test people shortlisted are supposed to give preferences for the projects. In all there were 24 positions last year which may change this year. After giving preferences students are called for interviews by matching the preference list with the marks scored in written test. Mostly you’ll get to appear in at least 2 interviews which are your top preferences.
The interviews in IIT Bombay are pretty chill (based on my experience with other IIT's) in the sense that RAs are supposed to have practical knowledge, your previous experiences and projects help you here. In other IITs the focus is on any one subject of your choice which requires in depth knowledge about the subject, the professors are relentless and unless you are very sure about what you say there is no way to get past them. In IITB the focus is on practical aspects more than theoretical knowledge about an Academic subject, so if you are comfortable with linux, or you have done a project in Java, ML and any other subject which is generally not asked in GATE you are in luck and this would be your best bet to make it.

This is the list of RA positions available last year.

1) Computer Centre sysadmin: Administrating servers and general Web Development 
Prof. Varsha Apte 
Positions available-4

2) PANDA- Related to developing benchmarks for low cost devices.
Prof. Varsha Apte 
Positions available-1

3) CSE sysadmin-Same as cc but only for cse department.
Subhadra Ma’am
Positions available-4

4) ASC-related to software development mostly business software and others applications used in iitb
Positions available-2

5) System security
Prof RK Shyamsundar
Positions available-3

6) Robotics and eyantra- concerned with developing low cost prototype boards for robotics education. 
Prof. Kavi Arya
Positions available-1

7) Machine learning- Prof. Ganesh Ramakrishnan
Positions available-2

8) C-USE - Centre for urban planning and resource utilisation Prof. Krithi Ramamritham
Positions available-2

9) IITBombayx- conducting, organizing and distributing MOOCs. Prof. D.B Phatak
Positions available-5

For additional information check out the comments at the following Facebook post:

https://www.facebook.com/groups/core.cs/1435736943125221/?notif_t=like&notif_id=1487659211038342

1. Which Encoding Technique its using in Fast Ethernet
2. Something related to flow Control and access control (Don't remember the exact question)
3. you have worked on android so do you know about android Database and its supported data types ?
4. Why linux has become very much popular ?
5. Basics about pointer and some operation using this ?
6. What is Race conditions ?
7. What is Shared Memory ?
8. One program output they asked to me (There was a board to explain the concepts didactically in case you need or you are asked )

My interview was on Third day (13th June,2018). There are 4 panels for CSE, named panel 11 to panel 14. I was in panel 14 and serial number allotted is 7 hence my interview was completed around 11:30 AM.

 

PS : This distribution of students in 3 days and 4 panels are totally random procedure. Don’t try to relate your exam performance with your day and panel and sequence number. now let’s go to the interview room.

 

There are three interviewers. As soon as I entered Interviewer2 asked to give my file and project report to Interviewer3.

Then interviewer2 started by reading my details, like from where I am, name of the college from where i’ve completed my B.Tech, my gate rank, my college cgpa etc.

(8th sem is running when I fill the form so that cgpa is upto 7th sem) I commented that final result is there and final cgpa is also there.

Interviewer1 : what is the reason of the increment in cgpa? Project work or some subject..

Me : final sem is project or internship.

Interviewer1 : so tell me about your project.

Me : answered.

Interviewer1 and 2 asked some question regarding project and related stuff eg : write in sequence all the system calls that client and server make for TCP\IP in socket communication?

Me: wrote on the board and explained.

Interviewer1: from your project it seem you are familiar with Dbms and OS.

Me: yes sir. I’m more comfortable with OS.(as I haven’t touched DBMS from long time and have good grip on OS)

Interviewer1: gave me a case => two process and one buffer. One process writes in buffer. Another take it and sort them and write back to buffer. First process again take sorted data. give a solution using mutex.

(the accents of professor is very different. I asked 4 times that I didn’t get the question)

After trying for many times i was able to give thme partial solution.

Then he handed over to interviewer2.

 

Interviewer2: do u know what is arithmetic mean?

Me : yes

Interviewer2: what is mean of first 5 even numbers?

Me: (calculated by hands in air and gave ans : 15 (shows complete nervousness) )

Interviewr2 : do u think mean resides outside the range?(all three laughed)

Me: wrote numbers on the board and gave ans.

Interviewer2: what is median of this numbers?

Me: same as mean.

Interviewer2 : what is mode of these series?

Me : i think no mode is present here bcoz mode is the number which occurs highest number of times in sequence.

Interviewer2: correct. Tell me that mean of any arithmetic series with odd number of terms and median of that series is same?

Me: maybe yes.

Interviewer2 : always?

Me: yes. It should be.

Interviewer2 : prove it on the board.

Me : (i don’t know how to prove this silly question and totally nervous but tried step by step and done it correctly)

Interviewr2: good. Thank you. You can go now.

 

It took almost 20-25 min.

Results declared on 20th : got selected for M.tech CSE

I-Interviewer, M-Me

I- What is your research interest?
M- Deep Learning, Machine Learning to some extent and Brain Sciences.

I- Draw the graph of y=$\frac{1}{(5-x)}$

M- Drawn ( take the mirror image of y=1/x graph across x-axis and then shift origin to
x=5, i.e., shift the graph 5 units forward on the x-axis.)

I- Tell me the role of double derivative in calculus?
M- It tells the rate of change of derivative(first derivative), if it is +ve, that means the
derivative is increasing which happens at a local minima point in a function, if it is -ve
we’ll reach a local maxima point.

I- How will you extend this concept to higher dimensions, like if z=f(x,y), then how’ll
be the double derivatives work?
M- Sir in that case we’ve to calculate partial double derivatives such as

(I meant to calculate the above) and check for particular conditions (which I didn’t remember but could possibly be
“Second Partial Derivative Test”) to see if it is a maxima or minima.
(‘I’ not much satisfied)

I- What is the derivative of a vector w.r.t. another vector?
M- couldn’t answer.(maybe the solution is a Jacobian Matrix.)

I- Do you’ve idea about gradients, like how are they useful in Machine Learning or in
general?

M- (possibly gave wrong answer ) Gradients help us to determine shape of the curve
which would help us to know maxima or minima and help in optimization. (‘I’ not
satisfied and cross questioned about what I said but I wasn’t able to elaborate and was
musing)

I- What is the role of Eigen Values and Eigen Vectors like in Principal Component
Analysis?
M- I haven’t digged deep into the maths of ML/DL but worked with the coding part.

I- How do you calculate Eigen Values and Vectors?

M- We solve $|A-λI|=0$ for Eigen Values and $\text{(A-λI)}\text{X=0}$ for Eigen Vectors.

I- Give an algo to find rank of a matrix?
M- Convert to row Echelon form, and then check number of non zero rows, basically
the number of independent rows.

I- Is row rank equal to the column rank, what is the proof that the row rank is equal to
the column rank?
M- Yes they are equal. Couldn’t give the proof.

I- Have you read anything from systems like OS etc?
M- No sir.

I- How will you store a sparse matrix?

M- Will store in a linked list, for every row a central node connected to all non zero
values in that row. (like a sparse graph stored in an Adjacency List)

I- How can you store them in an array?
M- didn’t remember(but the answer would be possibly using each non zero element as
a tuple (row, column, value) and store them in a n$\times$(no of non zero elements) sized
array.)

I- Suppose I’ve a polynomial of very very high degree, how’ll you store them?
M- Using linked list.

I- Can you write the structure of that linked list node you’ll use in that case in C?

M- struct node{
int coeff;//coefficient
int exp;//exponent
Struct node* next;//pointing to next higher degree of the polynomial
}

I- Suppose you’ve an m-ary complete tree with n nodes, what’ll be the height of the
tree?
M- $log_mn$

 

I- Create a BST from keys 10,5,4,20,15,11,30, tell me the number of levels and height?

M- Height=3

I- How’s the height 3 and what’s the number of levels?
M- Max root to deepest node distance is from 10 to 11 and no of edges in between is 3,
so height=3, No of levels=4, level 0(10), level 1(5,20), level 2(4,15,30), level 3(11).

 

I- What’ll be the avg comparisons to find a key in that BST?
M- approx 2.
(1 comparison to find 10, 2 each for (5,20), 3 each for (4,15,30), 4 for 11,so
avg. comparisons = $\frac{1\times1+2\times2+3\times3+4\times1}{7(total\text{ }elements)}$ = $\frac{18}{7}=2.57$)

I- Show me the exact fraction that you got?
M- $\frac{18}{7}$( ‘I’ satisfied)

I- No of BST possible with ’n’ keys?

M- $\frac{ \binom{2n}{n}}{(n+1)}$ Catalan Number

I- So you mugged it up, tell me how it is derived.
M- It is derived from the below recursive equation, suppose I choose a particular key
for root, now among (n-1) keys left, select ‘x’ keys for the left subtree, (n-1-x) will be
left for the right subtree, let T(k) denotes the no of BST possible with ‘k’ keys. Then,
$\text{T(n)} = \sum_{x=0}^{n-1}\text{T(x)}\times\text{T(n-1-x)}$.

I- Expand the expression for n=2 and 3.

M- T(2)=T(0)$\times$T(1)+T(1)$\times$T(0)=1$\times$1+1$\times$1=2
T(3)=T(0)$\times$T(2)+T(1)$\times$T(1)+T(2)$\times$T(0)=1$\times$2+1$\times$1+2$\times$1=5
I- Ok, we’re done.(Interview ends)

 

(P.S. — My interview lasted for around 30 minutes. I might have missed some
questions, and the above portray the picture of what I could remember, vague or exact.
I personally feel that they put so much emphasis on Calculus and Linear Algebra
because of my research interest being Machine and Deep Learning. They spent quite
significant time on my research interest rather than on just GATE subjects basics, so
basically you’ve to brush up in depth and read more and more proofs on concepts in
basic CS subjects(Data Structure, Algo, Engineering and Discrete Maths, OS,
Architecture etc.), read your research interest well, and good amount of mathematics,
starting from higher secondary to graduation level.)

I had my IISc Mtech(Research) interview from the CSA department scheduled on 25th may 2:00 PM.

The process consisted of written test followed by the interview on the chosen background subjects based on research area chosen.

We were given 30 mins for 10 questions,we had to attempt all of them. Questions were

(1)A simple C code. We need to tell the output.

(2)Given a grammar S->aSa | bSb | a|b. What language does it generate?

(3)Given a B+tree in which the maximum number of keys in any non-root node were told. We were asked to tell the minimum number of keys in any non-root node.

(4)Question-based on Unix Inode, finding maximum size of the file in file system.

(5)Cache size, block size, associativity and physical address length is given, find the length of tag bits.

(6)Some functions were given, arrange them in increasing order of asymptotic complexity.

(7)Given a max-heap representation as an array A, what would be worst case time complexity to search for an element?

(8)Two dices are rolled. Let Y be the maximum of two outcomes. The expectation of this random variable Y.

(9)Given a non-singular matrix A, with eigenvalues $\lambda _{1},\lambda _{2}....\lambda _{n}$.Given a non-singular matrix R, find the eigenvalues of RA²R^-1.

Within 10 minutes results of the interview were declared and I was shortlisted for it.

Chosen areas:

Main Research Area-Computer Systems

Sub-Area: Database and Computer systems Security

Background subjects: Data Structures and Algorithms, Engineering Maths.

Interview: The interview panel consisted of three professors and they had my application form beforehand.

I will refer I for the Interviewers and M for myself.

Questions asked were

I: Given a binary tree and a traversal order can we construct it uniquely.?

M: To this, I replied that we need inorder and anyone from the postorder, preorder or levelorder.

I: why do you specifically need Inorder.Why not any other order?

M: I told them that Inorder provides us with the details of the elements present in left and right subtrees of an element.

Now came another question

I: Given an arithmetic expression, can you draw an expression tree?

M: Yes sir.(now got tricked!!)

I: But now only you said you need two orders for constructing a binary tree, now in this case how can you construct the expression tree.

M: Sir, because in the expression we know the associativity and precedence of various operators using which we can draw expression tree.

But the interviewers didn't seem to be impressed by this answer and they were expecting something else.

I: Okay Ayush. Let's take a linked-list and an integer n. Design a function which will delete the nth node from the last.

M: I thought and told them first we can count the number of nodes in the list and accordingly take pointers and make the delete operation.

I: You are not allowed to count the number of nodes in the list!!.

M: I got stuck now!. I thought a lot but was unable to answer.

I: You can take multiple pointers if you want.

M: Since I was completely blank at that moment, I didn't get to know how to use the above hint that was given.(Yes, Multiple pointers!!).

I: Okay Ayush! We'll ask you some other question.

I felt bad as it was the initial phase of the interview in which I failed to make an impact. Still, I waited for some good things to come.

I : You have a graph with n labelled vertices. How many undirected graphs on these labelled n vertices?

M: Answered as $2^{\frac{n(n-1)}{2}}$. Explained to them how this expression came. Whatever I was thinking, I was telling them. They guided me accordingly.

I:Okay. What this term $\frac{n(n-1)}{2}$ is called?

M: I told them this is half of the degree sum of the vertices or the maximum number of edges in a graph or result of handshaking lemma.

I: No no!!, it's something else!!.

M: I was puzzled. What more it could be now I was thinking inside.

I:aaahh it's $\binom{n}{2}$.!!

M: Yes sir. That evaluates to exactly this :D

I: And, what would be the result in case of directed graphs?

M:I replied it's $2^{n(n-1)}$

I: It's correct!. Do you know graph isomorphism?

M: I forgot that the adjacency matrix for an undirected isomorphic graph are similar and not equal always, but said they were equal.

I: No, they are not same. They could be permuted in some another way.(He gave a hint about the existence of a permutation matrix which can transform one matrix to another in case of isomorphic graphs).So, give me a mathematical expression for graph isomorphism?

M: I was again puzzled(Mathematical expression??), so I told them the definition of isomorphic graphs.

I: Okay, given a cycle on n vertices which is isomorphic to its complement. Can you find n?

M: I started to solve it, and was stopped in between as they said: "Yes, you can find n okay stop!".

I: Ayush, you have chosen your sub-area of research as computer systems security.

M: Yes sir.

I: So, what all do you know in that?

M: Sir, I know all the protocols that we have studied in network security.

I: Please name a few of them.

M:Diffie hellman, RSA, Digital Signature, DES.

I: Okay, what is the pitfall in Diffie Hellman?

M: I explained him the scenario of Man in the middle attack without actually naming this phenomenon.

I: What this phenomenon is called?

M: This is known as the man-in-the middle attack.

I: Yes, and what do you do to prevent this?

M: We can authenticate users before going for the process of setting up key.

I: How do you authenticate users?

M: We can use digital signatures.

I:Yes, we can use it.

Okay Ayush, let me give you a scenario based question.

(I was like OMG. What scenario it may be. Okay let's deal with it)

M: Yes sir Please say.

I: Given a Web-application that runs on a server, this Web-Application uses a database, makes some modification to it and at the end of the day saves the database to a hard disk present on some remote location. Now, an intruder comes up and corrupts this database. Next day when the Web-Application will start, how will it come to know that the database is corrupted?

M: I thought a bit and answered that we could save the last modified attribute of the database, store it in some encrypted format at both places the web-server and the hard-disk and when the next day Web-application starts up it can check whether this last update is same or not.

I: But the intruder can modify the database and can still keep the last modified attribute to be same.

They were expecting some different answer.

I: There are many approaches to this, tell anyone.(He gave me a further hint).

M: I thought of the checksum approach but then was sceptical about it because the database will be large. But, I told him this approach.

I: Yes this is a nice way. Good!!.

I: Okay Ayush, we are done.
 

Overall, I liked the experience at IISc.The professors were extremely helpful and were not in any hush-hush to get an answer. Enough time was given to think, correct and re-answer on each query. And the best part is they try to make you comfortable as in when you enter the interview room.

Final Status: Not Selected.

$\text{IISc CSA MTech (Research) Interview Experience}$

$\text{Gate Score-}$ 759   $\text{Gate Rank}$- 410
$\text{Category-}$ General – EWS

$\text{Research Area –}$ Intelligent Systems
$\text{Background Subjects- }$
1. Linear Algebra 
2. Probability

Interviews were conducted over a period of 5 days (20^th  to 24^th   May). Each day there were 2 slots morning (9 am) and afternoon (2 pm). Mine was morning slot on 22^nd May.

$\text{Written test –}$ 9 to 9:30 AM
There were 10 questions of easy to moderate level. I attempted all the question out of which 7-8 were correct to my knowledge. For the rest 2 questions, I just wrote my approach.

$\text{My advice on written test-}$ 
1. Write your solutions clearly. Coming to the final answer is not that much important. They are more interested in your approach.
2. Try to attempt all the questions.

After half an hour (at 10 AM), results were out and I was the 1^st one from the intelligent system pool to get interviewed in that slot.
I was called in at 10:05 am.
The panel consisted of 3 professors.

$I_1$ –  Soumya, You have graduated from Indore Institute of Science and Technology and you have a CGPA of 7.60
$Me-$ Yes sir.

$I_1$ – Your graduation year is 2017. So what have you done in the past 2 years?
$Me-$ Sir, I had taken the decision of appearing for GATE after my B.E. Last year I got some lower rank so I again took the full-time drop for GATE. 

$I_1$- Ok Soumya, So your GATE 2019 SCORE is 759 and rank is 410.
$Me-$ Yes Sir.

$I_1$- You have applied in 3 departments. CSA is your 1^st  preference, CDS is 2^nd   and Electrical is 3^rd .
$Me-$ Yes Sir.

Then he asked me about my other interviews and other offers that were in my hand. 
$I_1$ Ok Soumya, You mentioned background subjects as linear algebra and probability. Should we start with linear algebra?
Me – Yes Sir. 

$I_1$ Which topics have you prepared in Linear Algebra?
$Me-$ System of linear equations, vector spaces, Eigen values and Eigen vectors.

$I_1$  We should start with eigenvalues and eigenvectors.
$Me-$ Sure sir

Till now 5 minutes have passed. Then they sent me to the whiteboard.

$I_1$- What are eigen vectors?
$Me-$ I wrote $Ax =  \lambda x$ on the board. Sir, x will be an eigen vector of A- if I give vector x as input here and if the output vector  $\lambda x$ comes out to be in the same direction as x.

$I_1$- Why eigen vectors are non zero?
$Me-$ Sir, they are defined as non-zero (I could have explained it properly but at that time this is what came out of my mind).

$I_1$- What are eigen values?
$Me-$ Explained it properly. 

$I_1$- Can you explain how you came to this equation $(A – \lambda I)x=0 $?
$Me-$ Explained.

$I_1$-Why determinant of this matrix  $(A – \lambda I)$ is zero?
$Me-$ Sir, As null space of this matrix, contains non zero vectors, columns of $(A – \lambda I)$ are linearly dependent. So this matrix is non-invertible hence its determinant is 0.

$I_1$- If matrix A is $nXn$ then how many eigenvalues will it have?
$Me-$ Sir, the degree of the characteristic polynomial of A is $n$. A polynomial equation of degree $n$ has $n$ roots and as roots of the characteristic polynomial are the eigenvalues of A so A will have n eigenvalues.

$I_1$- Can matrix A be rectangular?
$Me-$ No sir. We need to equate the determinant of $(A – \lambda I)$ to zero and determinant is defined for square matrices only.
(At this point, I was disappointed with my answer 😑).

$I_1$- Suppose matrix A is $3 X 3$ 
Write on the board – $A^3 = 0$ . Find the determinant of the matrix $A-3I$
Is this information is sufficient to find the determinant?

Initially, I was able to find one eigenvalue of A i.e 0 but with the help of a small hint, I got all 3 eigenvalues of A. Still, I struggled to find the determinant.
Then somehow I reached to the trace of (A- 3I).

$I_1$- How the trace of this matrix (A – 3I) is $-9?$
$Me-$ Explained.

$I_1$ - Ok. we should proceed further.

After this, I was handed over to the 2^nd  professor.

$I_2$- What is your GATE year?
$Me-$ 2019 

$I_2$- Oh, you gave the GATE recently so subjects must be fresh in your mind. 🙂
$Me-$ Yes sir 😊

$I_2$- Let's start.
I have given you a six-faced dice. You have to roll it until you get the 1^st   even number. For Ex- you rolled it for the 1^st   time and got a 3 so you rolled it again. You got 1 now. You rolled again. You got 6 this time. Now you stopped. So what is the average number of times you have to roll the dice to get an even number for the 1^st  time?
Do you understand the ques? Repeat it once, what you have to find?
$Me-$ Yes sir. Basically, I have to roll the dice until I get the 1^st   even no. I have to find the expected number of trials until I get the 1st  success.

$I_2$-– Exactly. So find it.
$Me-$ Sir I can model this situation using a geometric random variable

He stopped me in the middle. 

$I_2$-, Correct. So as you said Random Variable. First, explain it.
$Me-$ Explained.

$I_2$- What is a geometric random variable?
Explain it on the board.
I explained it properly.

$I_2$- Now model the given scenario and find the expectation. 
I found the required probabilities and derived the expectation of a geometric random variable using its memorylessness property.

When I was busy in deriving the expectation, I heard some voice from the background. When I turned they told me that I am going excellent. It boosted my confidence.🤩

$I_3$ (who remained silent all this while)- From where have you studied probability?
$Me-$ Sir- MIT OCW lectures. (I forgot the name of the professor- John Tsitsiklis 😔)

$I_3$- You have studied probability solely for GATE or this course was there in your B.E?
$Me-$ No sir. I studied it only for GATE.

$I_3$-- Ok. Complete your proof.
I completed it in the next 3 minutes 

$I_2$ asked me to explain the memorylessness property mathematically and how I used it in one of the equation.
After a few hints, I was able to explain everything. 

$I_1$- Ok Soumya, We are done with the interview.

$I_3$ – As you mentioned ML and DL as your sub areas, are you open to other areas as well?
$Me-$ Yes sir. 

The interview lasted exactly for 30 minutes. I came out exactly at 10:35 AM.
It was an amazing experience.

25^th May 2019 -the list of shortlisted candidates declared and my application number was there on the list.
5^th  June  4:07 PM – Received a mail – $\text{IISc Admissions 2019- MTech (Res) Programme Offer Letter.}$ 😍

                My GATE 2017 rank is 101 and I was targeting IIT Kanpur and IIT Delhi for admission. So in this blog I am writing about my tests experience at IIT Kanpur.

                This year they called around 400 people for the test. They conducted 3 tests(Objective, Programming and Subjective). They conducted Objective and Programming test on 13^th May. On the basis of these 2 tests, they shortlisted around 180 people for Subjective test which was conducted on 14^th May. Among all these 3 tests, Objective test was the easiest one.

 

•  Objective Test

                Objective test consist of 3 sections(Theory, Systems and Statistics & Data science). Each section was of 50 marks and we have to attempt any 2 sections in 3 hours. There were some fill in the blanks and one line answer questions too and for the questions with options, more than one option can be correct. There was no negative marking. Some of the questions asked in this test are :

1) Theory

i) 8a + 19b = 1. So find out the possible values of a and b.

ii) one dfa was given and we have to choose the correct regular expression for it from the options given

iii) DFA was given and the probability of each link in DFA was also given. So we have to find the probability to reach a particular state using the given 2 strings.

2) Systems

i) A question on semaphore to find initial value of semaphore variable

ii) To find number of hosts in a network given the subnet mask

iii) Difference between clustered and non-clustered indexes

iv) Number of clustered and non-clustered indexes

v) A query is given with EXIST clause and we have to rewrite it without using EXIST

vi) A question on finding accuracy of Branch prediction. A DFA was given for it and program sequence was also given telling whether it will take the branch or not

 

• Programming Test

                    I am not able to recall questions from Statistics & Data science because I attempted only theory and Systems section. Next was the programming test. There were 4 programs to solve in 3 hours. Marks of each program were 30, 40, 60 and 75. The questions asked where :

1) Question to check anagram ( 40 marks )

2) Starting index of leaves and value of leaves of complete binary tree where given, with the property that parent will have min(left child, right child). We have to return the the contents of indices asked for the tree. ( 30 marks )

for example,

starting index = 3 and

leaves values are 1, 9, 5 and 2

above 2 information will be given, So the tree will be like

    min(1,2)=1

    /               \                                                      1

min(1,9)    min(5,2)          =>                       /     \

  = 1           = 2                                                1        2

 /     \        /     \                                           /   \      /  \

1     9      5      2                                           1     9    5    2

3) There are p prisoners and c ( > p) cell blocks. c and p will be given as input. Also a sorted list of c integers will be given. You are required to choose p integers from c integers such that the minimum distance between adjacent prisoners is maximized. You have to output this minimum distance. ( 60 marks )

4) We have to find addition factors of a number in lexicographic order for n<15. ( 75 marks )

for example if n=4 then output will be

1 1 1 1 

1 1 2

1 3

2 2

 

• Subjective Test

                     Finally there was a subjective test similar to objective one. We have to attempt questions from any 2 sections in 3 hours. There were 3 questions from theory and 3 questions from Systems. Questions asked where :

1) Theory

i)  

a) if degree of vertices < 3, then prove that the graph will be union of vertex disjoint path and cycle.

b) Graph Matching was explained. Let S and R be the matching graph, then a new graph G=(S-R) ∪ (R-S), will be union of vertex disjoint path and cycle. Also prove that the cycle obtained will be of even length.

ii) Consider a grammar G with productions P. Let INIT(G) be the grammar with production P' such that

    P' = P ∪ ( A->B | such that A->BC belongs to P ) ∪ ( A->epsilon | such that A->b belongs to P )

    prove that:

a) Prefix(G) is subset of INIT(G)

b) INIT(G) is subset of Prefix(G)

iii) Algorithm to find strongly connected components in the graph

2) Systems

i) Question on semaphore. A program was given which was incrementing variable y. 8 processes where allowed to execute the program. Initial value of y was given. We have to find possible values of y after all 8 processes complete their execution.

ii) Information about main memory and cache was given. We have to find number of bits for tag and index for direct mapped, set associative and fully associative cache. We also have to find cache capacity including tag overhead for each cache. Also explain the working of each cache mechanism.

iii) I didn't understood this question.

 

                                I have written as many questions that I recall. If you guys remember any more questions especially for objective one, write in the comment, I will add it.

Verdict :-  Selected :)

Initially for MINDS(IITD) or CMINDS(IITB) there was a written test, if you qualify then you will proceed to the interview round.

You can follow the link given below for the syllabus. As both the written tests (no -ve marks) was more or less the same:

https://bit.ly/3Or8Nrw (IITB CMINDS)

 

In IITD there were 3 coding questions in addition to MCQs & MSQs and the test was conducted on HackerEarth platform.

 

IITD Interview Questions and Resources:

Around 40 people were shortlisted for the interview.The interview was conducted on 3rd June 2022(Till that time 3 coap rounds were over).My interview was scheduled at 4pm on Microsoft Teams.In my panel there were 3 professors.Each professor asked me questions from different subjects(given below).And the interview lasted for around 40-50 mins.

 

General Questions:

1. Give a brief academic introduction about yourself.

2. Currently what offers do you have?If you get M.Tech will you consider it or stick to MS(R) program and Why?

3. What are your favorite subjects? (Best answer, Linear Algebra & Probability for AI and Data science profile interviews.)

Also go through basic AI/ML stuff. Resource: https://bit.ly/3xy4tzO

 

Linear Algebra:

Take an equation Ax=B

1. Explain the solution of the system of linear equations w.r.t column space?

2. When will the system have a solution?

3. If matrix A has full rank, then for what B vectors does the system have a solution?

4. If the B vector doesn’t lie on the column space of A then how to get an approximate solution(projection concept)?

Resources:

https://bit.ly/3Qza41C (Must read upto 23rd video)

https://bit.ly/3xIokMP (Alternative to above resource)

 

Calculus:

1. What is a convex function?(Read thoroughly about concave & convex functions).

2. What is gradient?Give its geometrical significance.

3. What's a directional derivative? 

Resources:

https://bit.ly/3OdsK5h (Must read Gradient section thoroughly)

https://bit.ly/3zOvvpc 

 

Probability & Statistics:

1. What is covariance for 2 random variables x & y?

2. Proof that for independent random variables covariance is 0.

3. Prove E(x+y)=E(x)+(y) for both independent & dependent cases.

4. Prove E(xy)=E(x)E(y) for an independent case.

5. A coin is tossed n times we define a random variable as follows,where xi is ith coin toss, prob. of head in each toss is p(success):

     Find E(x(bar)) and Var(x(bar)).(Use linearity of expectation concept)

 

Also do read thoroughly joint pdf,pmf, conditional expectation,total expectation,CDF etc.

Resources & Tips:

Keep handy all the distributions equations and graphs,specially normal distribution and approximation of poisson & binomial distributions using normal distribution.

Also go through proof of the memoryless property of geometrical & exponential distribution.

 

Recommended videos:

https://bit.ly/3OtYFhK (Must read upto 98th video)

https://bit.ly/3OoqmbC (Sampling distribution concept)

https://bit.ly/3n1d499 

https://bit.ly/3OaaZ6O 

https://bit.ly/3HBPE3G (Just go through week 3 important set of problems)

 

Algorithm:

1. Suppose you need to climb a stair of n steps and you can take at a time 1 step or extend your leg and take 2 steps or 3 steps at a time.Finds number of ways you can climb n steps.

 

(Hint: Take sol. as T(n).For T(n) we have 3 tree branches T(n-1)(taking 1 step at a time)/T(n-2) (taking 2 steps at a time)/T(n-3) (taking 3 steps at time) then again solve the subproblems of size (n-1)/(n-2)/(n-3) )

 

Verdict: Selected (IITD)

 

Note:

1. If you have a 650+ Gate score(Gen) you should definitely prepare well ahead as you will most probably get a call.Applicable for all branches.

2. IITB focuses more on LA & Prob.(specially joint distribution which was not part of the GATE syllabus).You have to study beyond the GATE syllabus.

3. You should never go out of studies after GATE for a long time else it will be difficult for you to crack the interviews.

4. Must be prepared with the B.Tech final year project.

 

Best of Luck for your selection :)

 

                                

Hello everyone.I hope you all are doing well.

Here are my GATE 2021 credentials:

Name-Akshat Kumar

GATE Paper:CS/IT

Rank-206

Score-798

Category-Non EWS General

B.E/B.Tech branch-Printing Engineering

Since I had less chances of getting CDS coursework and was anyway somewhat more inclined towards research, I decided to apply for MTech research.

Firstly,candidates where shortlisted based on their GATE scores for the written test which would be used to shortlist for interviews.Unlike 2020 where cutoff was an astonishingly high 845 GATE score for written test, this year the cut off was a generous 700.

I don’t exactly remember the questions but there were 9 MCQ questions,7 Mathematics(Linear algebra,Probability,Graphs) and 2 Programming.

7^th May,2021: Written test:

1 question was on graph plotting,1 question on Baye’s theorem, 2 questions based on Eigen values, 1 question on general probability and 2 questions had all options incorrect as far as I remember. For programming, there was 1 question on spiral traversal of matrix and another was called Dominant Matrix in which we had to find number of rows in which magnitude of diagonal element  was greater than magnitude of all other elements in the row.

The test was conducted on HackerEarth Platform and was 1 hr 15 mins in duration.I attempted all questions except spiral matrix as I didn’t have much time left.

I was shortlisted for interviews after which we had to fill our lab preferences.I filled VCL AND BCL(Visual computing and Biomolecular computation labs). We also had to give Statement of Purpose for each of the labs we wanted to join.

17^th May,2021:Interview:

The interview was conducted over Microsoft teams.There were 4 professors in the call.Here is my interview (Ix=interviewer x):

I1:Read out my application form details like GATE score, B.E degree and Labs preferences.

Me:Confirmed

I1:What topics have you come prepared for Akshat?

Me:Sir, linear algebra,probability,DSA and image processing basics.

I1:Starting with linear algebra.Can 2 matrices with different elements have same eigen values?

Me:(after thinking for a moment)Yes sir,

I1:Can you give me an example?

Me: Gave example by keeping major diagonal elements same and using favorable minor diagonal elements,sometimes making Minor diagonal product zero and sometimes making one of the elements as 1.

I1:That is a pretty good example.This is a property of matrix. We write it as A=PBP^(-1).

Me:Oh yes.Isn’t this condition for diagonalizable matrices, sir?

I1:Yes,good observation.Now can you prove that the two matrices A and PBP^(-1) have the same eigen values?

Me:Asked permission for using pen and paper and started thing along the equation A.X=lambda.X

     After few minutes I was able to prove this and showed the solution on camera.

I1:(quite impressed)That is a really good proof. I2 now you can ask him questions.

I2:Are you comfortable with probability?

Me:Yes sir.

I2:Ok,suppose you are in a class of 30 students,what is the probability of having a birthday common with atleast 1 student in the class?

Me:Again used pen and paper.Thought in terms of discrete random variables.Say X represents number of students with whom I have a birthday in common.So basically I need to find P(X>=1) which is same as 1-P(X=0).

P(X=0)=(364/365)^29 

So P(X>=1)=1-(364/365)^29.

I was also narrating my steps to I2 while solving.So I gave answer like this.

I2:Good.So what will your answer be approximately.

Me:Sir its a difficult calculation but would be close to 0.99.(Realized my mistake immediately and corrected)Sir actually 364/365^29 is close to 0.99 so probability would be something like 0.01 .

I2:Ok.So now suppose we have 400 students instead of 30.Would the probability increase or decrease?

Me:(A bit confused)Sir i think it would decrease.

I2:Are you sure?

Me:(Realized)No sir, actually since the number of students have increased, there is higher chance of having a common birthday and also 364/365^399 would yield a smaller value so 1-364/365^399 would have a larger value.

I2:Ok good.I3,would you like to ask some programming question(probably because my B.E was in printing XD).

I3:Yes.So can you write a program to find largest and second largest numbers in a given matrix.

Me:Yes sir.First I wrote a code finding largest in one pass and second largest in another pass and narrated the logic to I3.

I3:Ok that’s fine,can you optimize it, like try to do this in one pass.

Me:Did that.And showed the psuedo code on camera.

I3:Ok good.I4 do you have any questions?

I4:No I am fine.

I3:Ok Akshat.Your interview is over.We will now disconnect the call.

Me:Thank you sir.

My interview lasted only about 18 mins including introductions and salutations, which was relatively short,probably because I didn’t struggle much with any of the questions(not boasting).Overall, interview was great and it felt great to be interviewed by the best minds fro one of the best research universities in the world. The professors were very friendly and as far as i felt, will always guide you through if you are stuck with some question.I would definitely recommend Gilbert Strang’s MIT OCW lectures on linear algebra to be thorough with theoretical understanding of the same.First 15 lectures should suffice.

26^th May,2021:The provisional shortlist was released and my application number was on the list.I was really happy but still had some fears since there is always some chance that you may not make it to the final list although such chances are less if your interview went quite well like mine.

10^th June,2021:Received offer letter in mail at 7:09PM. My happiness  knew no bounds.From B.E in Printing Engineering to AIR 206 in GATE CS/IT followed by M.Tech Research at IISc CDS, what a journey this has been, I imagined as I watched my parents shed tears of happiness :’) .Thank you all. I hope I helped you somewhat and hope to see many of you at IISc next year.Cheers. :D

 

 

 

#Feb23  #Interview Experience   #Chennai

Hello friends !! Good morning..
This post is for those who may give ISRO interview in the coming months . I am going to share my interview experience in the below lines . I will try to cite the questions that were being asked to me as far as my memory goes.

My interview was scheduled at 3rd from the last. So I had lunch and Friday prayers then waited patiently and tried to stay calm and confident. It was roughly 4:45 pm when my name was called for the interview. So here the experience goes(I am mentioning the questions along with the answers which I gave) :

Interviewer : Introduce urself
Me : Introduced myself to all.Told about my graduation college and about my current job i.e. in BSNL.

Interviewer : Tell me about the subjects u have learnt in ur B.tech
Me : I mentioned Mathematics , Computer Architecture and Theory of Computation

Head Interviewer : What is Flynn's classification of architecture.Name them.
Me : Answered each of the types .

Interviewer : How does out of order execution occurs in pipe lined environment ?
Me : Answered.

Interviewer : What are the types of the hazards which are there in pipelining ?
Me : Answered.

Interviewer : What are the different types of data hazards ?
Me : Answered with elaboration.

Interviewer : What are the ways to reduce or eliminate control(branch hazards) ?
Me : Answered with elaboration.

Then questions on Maths were asked.They are as follow :

Interviewer : Explain about lattice.
Me : Explained properly

Interviewer : Some mathematical modelling problem.
Me : With a bit of hint from their side , I could come to the conclusion and answered rightly that it was related to bipartite graph.

Interviewer : What is Taylor's Theorem ?
Me : I clearly admitted to them that I was unable to recall as I studied about it way back in 2nd semester.

Interviewer : What is bijective and surjective function ?
Me : Explained

Then some questions about Theory Of Computation.

Interviewer : What are the types of grammars ?
Me : Answered and elaborated [ Type-0 to Type-3 ].

Interviewer : What is the practical use of regular and context free grammars ?
Me : Answered.

Other interviewer : Which programming language u r comfortable in ?
Me : I was very straightforward in this and told "C" bcoz I do not know each and every things of OOPS in C++ and also as far as Python is concerned , I know the basics of it only.

Interviewer : What r the command line arguments in int main()
Me : Answered.

Interviewer : To read or write from an arbitrary location from file , which function we need to use ?
Me : Answered(It was fseek() function)..

Interviewer : What does ls command do ?
Me : Answered.

Then some project related questions are asked regarding working and some basic terminologies behind it .

Interviewer : Tell me the pros and cons of collaborative and content based filtering .
Me : Answered .[My project was based on content based filtering]

Then the head interviewer took notice of the fact that I know six languages via the bio data form that they provided to fill prior to the interview.

Head Interviewer [In an appreciating tone] : How do you know so many languages ?
Me : Explained the reason behind each of them.

Finally some non tech question to conclude.

Interviewer : You are currently working in BSNL and that too in ur home state.. So what has made you think to join ISRO ?
Me : As a responsible citizen of our country , we are obliged to serve anywhere throughout the country.

Interviewer(Counter question) : That BSNL also does..So why ISRO ?
Me : Beyond doubt BSNL is also obliged to serve countrywide.But as far as ISRO is concerned , it is based on space science which has wider implications on the society.

[To add on] I got the inspiration to work in ISRO from Honble Late Dr. A.P.J Abdul Kalam with whom I interacted personally while I was in Class 10th..His zeal , simplicity and enthusiasm to work selflessly for the country has inspired me to move on..And hence if I am given a chance to serve ISRO in case I am selected , then I will give my best to serve my nation and the society.

The interviewers appreciated my answer and responded positively.The interview lasted for around half an hour.[By and large , others had around 15-20 minutes of interview].

In a nutshell , this interview was one of the nice interviews I ever had irrespective of the result which is yet to come..Though I look forward to it positively as the reaction of the interviewers was positive as far as I have felt.

All the best to you all..N plz pray for me as well so that I get selected in ISRO finally..

 

This is coming from a 2020 B.Tech CSE graduate who wrote GATE.

I had the opportunity to sit for IIT Madras MS interview during the unprecedented corona times. So I attended the interview online over a Google Meet link. 

There were around 5-6 panelists. However, only 3 of them took my interview. The first professor very politely asked for my introduction. 

Q1) Tell me something about yourself. 
A1) Name, College, Subject interests etc. 

He being a Bengali himself and knowing that I did my graduation in Bengal, asked if I understood Bengali! 

Then he went on to handle the process to another professor. The next phase was Programming Assignment in C/C++. I was first asked to write a code that returned kth element from the start of the Linked List on a shared document. I only had to complete a function. There were no formalities like compiling the code although the function had to be completed with proper syntax in C. The same had to be modified then to return kth element from the end of the Linked List. 

After the programming test, I was asked the subject of interest for the next phase. I was comfortable with Data Structures and Algorithms so told them so. 

The third professor asked questions from the subtopic - Stacks and Queues. Initially, I was expected to give their definitions and other properties. He then went on to ask me about the implementation details of a queue using stack and vice versa. This question really got confusing as the professor wanted me to optimise the implementation and do minimum movements. 

The interview ended at a very good note as all the interviewers were helpful and polite. They assisted me whenever I got stuck at a use case or so. 
 

Verdict - Selected
(Although I joined IIT Kanpur M.Tech)

I still can’t believe that I am writing a success story after reading GATE success stories of others.

Hi everyone! I am Amit Kumar. I appeared for ISRO interview on 2nd August 2018 and secured AIR-17 in the selection panel. It was like a dream come true when I logged into ISRO careers page on the day result was out.

People asked me to share my interview experience, so I was keen to write it on gateoverflow as I have gained ample of knowledge from here.

Just a little background:

I belong to Patna, Bihar. I did my B.Tech in CSE from DIT School of Engineering (now Amity), a private college in Greater Noida affiliated to DR APJ Abdul Kalam Technical University. I am 2016 batch pass out.

My only dream was (in fact is) to get a single digit rank in GATE. But in spite of my all hard wok I have only the following statistics:

GATE 2016 : AIR-1269

GATE 2017 : AIR-546

GATE 2018 : AIR-1457

I was devastated after seeing my rank in 2018 at GO site before the result was actually announced. I didn’t even bothered to check my GATE result after that. I prepared for GATE 2018 along with job at Wipro.

Now my only hope was BARC and ISRO.

I prepared for BARC and cleared its written but was not selected in the interview in spite of an interview of around 1 hours 15 minutes. Another failure for me.

Coming to ISRO now:

Written Exam:

I got 124 out of 234 marks in the written. Just got shortlisted for the interview :P . Before that I made a blunder in filling up the OMR sheet. I did not filled and bubbled the center code at all. But I had a lucky escape.

Interview Experience:

Date: 2nd August 2018.

Venue: DOS staff Housing, Antariksh Vihar, Dwarka, New Delhi.

Time: 8.00 AM.

I reached at the venue at 7.30 AM. At 8.00 AM, document verification started. I was assigned a serial no. 4 luckily. I was asked to go upstairs and wait there for my turn outside the committee room. I was restless there, only thinking that it would be my last chance for this year. Suddenly, the doorbell rang and my name was announced.

My interview started at 10.10 AM. As I entered the room there was a U-shaped big table with around 10-12 (didn’t dared to count :P) scientists (P1, P2…P10) seated, with the panel head (PH) at the center.

I greeted them with a smile at my face and little fear in my heart.

PH: (smiling) Amit Kumar right….

Me: Yes sir

PH: Have a seat.

Me: Thank you sir.

PH: (looking at my bio data) so Amit u are 2016 pass out.

Me: Yes sir.

PH: What were u doing since then?

Me: Sir, I am working as a project engineer in Wipro Technologies.

PH: What is your job there?

Me: I am working as a JAVA developer there.

PH: What project have u done in your B.Tech ?

Me: Apparel recommendation Engine sir.

PH: Can u tell your favorite subjects?

Me: (I was expecting this question after reading interview experiences and was well prepared with GATE subjects) Computer Networks, DBMS, OS, DS, C Programming.

PH: Ok Amit. thats fine. You tell one subject from advanced computer science that u have studied in 4th year of B.Tech.

Me: (Shocked….  I had read many interview experiences. But none of them talked about this. I was cursing my luck. I thought that its all over for me…… but I thought for 20-30 seconds and then replied) Data Mining and Warehousing Sir (So that i will be able to relate it with DBMS).

PH: that’s good.

Then he asked one of the panel members to continue.

P1: So Amit, u mentioned computer networking. Bandwidth is 1 Mbps. What is the value of M here?

Me: Sir its 2^20.

P1: u know IPv6 ?

explained

P1: If I use 1 million IPv6 addresses per second then how long would it take to exhaust all the addresses?

Answered

P1: Can you tell some error controlling techniques used in computer networking?

Answered

P1: Can u write the CRC-32 polynomial ?

Me: Sir i dont remember the exact polynomial.

P1: What are the requirements of a network?

Answered

P1: What are the factors that limits network capability?

Answered

There were some other questions which I don’t remember exactly.

Panel head then asked the other panel member to continue

P2: So Amit u mentioned Data Mining and warehousing. What is a data warehouse?

Answered

P2: How is it different from normal database?

Answered

P2: What is OLAP and OLTP?

Answered

P2: How these 2 differ and where are they used?

Answered

P2: What is Big Data? How is it different from normal data?

Answered

P2: What are the steps involved in Data mining?

Answered

P2: What is a data cube? How is it constructed?

Answered

P2: Give an example of data cube and how its used in data mining?

Answered

P2: Consider a layered architecture of a database. Lets say 3 tier architecture of DBMS. Where the validation testing will be done?

Answered

P2: Who will do it at all the 3 layers?

Answered

P2: What is Business logic?

Answered

He went too deep in the 3 layer architecture, validation testing and the roles of various stakeholders in the validation testing at all the 3 layers. He also gave some scenarios and asked my approach.

I am skipping that to keep the length of the post in check.

 

Then came Programming language

PH: So Amit. Which programming language are u comfortable with?

Me: C programming sir.

PH: But U work as a java developer in Wipro. Why not JAVA?

Me: Sir I have implemented most of the data structures and algorithms in C programming that’s why.

Then panel head asked other panel member to continue.

P3: Can u write a program to compute the area of any given polygon?

Me: yes sir.

He asked me to go to white board and draw a polygon and tell the approach to find its area.

I drew this:

                                                                                                                                                                                                                                  

P3: How do you find its area?

Me: half * base * height.

P3: Draw a polygon with more sides.

I drew this :                                                                                                                                                                                                                                                                                                                                                                                                                     

P3: (Smiling) How will u find its area?

Me: Length* Breadth.

P3: Draw a random and complex polygon.

I drew this:

                                                                                                                                                                                                                                   

P3: How will u find its area?

Me: (Smiling) Area of rectangle + Area of Triangle.

All of them started laughing.

Then one of the panel member got up and said humorously: arrey yaar kya kar rahe ho (What are u doing). He took marker from me and said: Aankh band kro or koi sa bhi polygon bana do (Close your eyes and draw the polygon).

He drew something like this:

Then they asked my approach of finding its approximate area. They gave a hint: keep it simple.

I started thinking about it. Then they asked to think loud. I told them various approaches using numerical techniques. And thank god they look satisfied and said : GOOD.

Then came Data Structures:

P4: What are linear and nonlinear data structures?

Answered (the most expected question of any DS interview).

P4: Do you know Dictionary DS?

Answered and explained about it.

P4: How can we implement it?

Me: Using hash table.

P4: How can we detect a cycle in a graph?

Me: DFS and BFS

P4: How to detect it using DFS in C?

Answered

 

 

Next came Operating System

P5: What is fragmentation?

Answered

P5: What is internal and external fragmentation?

Answered

P5: How can we resolve the problem of fragmentation?

Answered.

P5: What is compaction? How will we do it?

Answered

Then the Panel head asked me to leave.

My interview lasted for around 20 minutes. It was like a rapid fire round.

Result: Success.

Prepartion Tips:

 

• I followed NPTEL and youtube lectures.

• However reading standard books are equally important and along with solving their exercises.

• Above wont work alone if we don't practice from GO PDF (The Brhamashtra).

 

I Would like to wish all the best to ISRO and GATE aspirants. However I am still a GATE aspirant and working for a single digit rank.

I would like to thank GATEOVERFLOW specially Arjun Suresh sir, Bikram Ballav sir and all others who are selflessly working to guide computer science students to their dreams.

Thank you 

 

My background: BE in E&TC with 2 years of experience with Tata Elxsi where I worked on computer vision algorithms for ADAS domain. Left the job three months before GATE-19.

PGEE entrance :

The registration for the exam begins usually in 1st week of March. The exam for the year 2019 was held on 29th of April. The syllabus for the exam is mentioned on IIIT-H’s website and is updated every year. Though they do not give comprehensive syllabus, we are expected to cover the topics based on GATE syllabus.

Exam pattern : The pattern seems to vary, but not every year. This years' pattern was different than the last year in the sense that there were no multiple-answer questions this year.

Aptitude section: 90 min, 45 questions (2 marks each)

Technical section: 90 min, 30(2 marks each) + 30(1 mark each)

My preparation for PGEE :

For covering technical section I went back to my notes for revision that I had prepared during my Gate preparation. For practice, I didn’t have any test series' active account as they are revoked after the Gate exam. So I took to solving previous Gate questions and some free available sample questions. For this I referred GO book and geeksforgeeks as they have topic-wise previous year questions as well as some practice questions according to Gate syllabus. Covering previous year Gate questions is a must as some of them are asked as it is in the exam which will not only save your time in exam but also help you in scoring well.

Aptitude section : This section is of 90 minutes. Hence fair bit of emphasis is put on aptitude. Also, the technical section is evaluated only if one clears aptitude section. I referred indiabix.com for covering aptitude topics as I only wanted to brush-up and get some practice. If somebody wants to study(meaning how you approach a certain type of problem) for aptitude, this might not be the right website as they do not provide the 'theory' behind topics and the formulae given are anyway of no use as you need not remember them. Hence refer this site only if you want to get some practice for aptitude, otherwise go with some standard book which covers 'theory’ (meaning how you approach a certain type of problem) and for practice. 

Note: Along with accuracy, speed is very important in the aptitude section.

The result of PGEE was declared within two weeks of the exam.

Interview :

Preparation : To start with, I referred previous year interview experiences available on PGEE Facebook group. This helped me to understand the pattern of interview and the abilities/topics they put emphasis on. 

I did my preparation with three broad areas in my mind : 

General questions : This included questions related to my profile. For ex. Why did I leave my job, why am I turning to CSE after doing BE in E&TC, why did I only opt for M.Tech and not MS. (and vice-versa, accordingly). The questions to prepare for, would be entirely based on individuals' profile.

CS subjects : It is advised to prepare at-least three subjects thoroughly. In the interview, you will be usually asked about the topic which you are comfortable with. I prepared for DS-Algorithm, OS and COA. It is advised to have Data structure-Algorithm as one of the three topics as they are anyway asked about.

Project work: This included preparing the projects I did while working with Elxsi and during my bachelors degree. I prepared for this based on organization of my resume. Since we are asked to submit resume during the registration itself, there is possibility that you might want to make some changes to your resume from the one available with them. Hence take copies of updated resume with you and if required ask them to consider this latest resume. I had to make some changes in mine, though they were not major so did not ask them outright to consider the one I was carrying. And anyway it did not affect the type of questions I was asked.

Doubts, for candidates appearing for interview :

I was called for interview on 13th  June, which was 4th  and final day of the interview process. All the candidates were distributed among 4 interview panels, with each panel interviewing 28-29 candidates. This was the case on all 4 days. 

We were to report at 8 am to Himalaya Building and were asked to sit in bodh-105 where the interview process was explained to us. The professor briefing us about the process cleared many doubts which I would like to mention here as they occur to almost all the candidates going for the interview.

• The interview dates are not given based on merit but are randomly assigned. So the one's called on later dates need not think that they are down in merit list or the one's called earlier are higher in the list.

• During interview, the panel do not refer to your Gate score as parameter for selection though they might inquire about it (you have option to mention it in the application form during registration).

• There will be no waiting-list at-least for the 2019-20 batch. The number of candidates to be selected are not fixed though they do have an upper cap on it.

• If you did not mention MS as an option in your application form but would like to be considered for it, you can tell this to the panel during the interview.

• The duration of interview has no resemblance to selection or rejection of a candidate.

• If you have time constraint on your return journey on the interview day and are allotted a slot later in the day, you can ask them to be interviewed before others. Though the reason must be genuine.

Finally, the interview :

I was in the list of panel-3 who were conducting interviews in Kohli Auditorium. There were three professors in the panel(supposed to be four, but one of them left while I was waiting outside for my turn). Hereon I will refer to the professors as P1, P2, P3. 

I entered the room and wished them for the morning.

P1 (asked for the folder of docs that I was carrying) : (Surprised), So you were working in Elxsi. Why did you leave such a job?

(This was more of an exclamation than a question).

Me- Gave my reasons.

Still he persisted with the question and asked me to explain the job profile (based on the experience letter attached in my folder) which turned out to be a sinner as the next thing he said was "You left a kind of job profile on which we do our research here. You were working in one of the emerging fields." And I must say, this was in no way a compliment but an utter exclamation. He was, in a way, displeased with my decision of leaving such a job. P1 asked me my Gate rank and said "you could have got this rank even while working" which did not help my confidence. After some more discussion they decided to move on.

P2 asked me related to my project mentioned in the resume. Again it turned into a discussion. They did not ask me questions based on implementation ( and I had emphasized a lot more on revising the implementation during my preparation) but on general scope of the application and improvisations that could be done. P2 explicitly mentioned "to think w.r.t research". I put some good points and some very silly one's which made them laugh as well. After another 'discussion' between us, they seemed satisfied and decided to move to some CS.

P1 asked me which topic I would like to be questioned on. ( I can't remember the exact word he used, but it was something which confused me whether he meant a broader topic which I worked on during my job or CS topics, as I was still in my "job" zone, contemplating the previous questions).

With confused face, I replied him with "Data structures and algorithms?" I realized its important to stay simple and calm when asked for choices.

P1 : How will you find if two strings are anagram?

Me : Gave a solution which he was convinced with.

P1 : Given two strings, find if one is rotated version of other and if yes, then by how many places?

I gave an algorithm flow, for which he took time to find a counter example on which it won't work. Meanwhile, he asked P3 to ask me few questions.

P3 asked me to draw graph of y = 1/x and then y = 1/|x|. I drew them.

By this time, P1 gave me a string on which the the algorithm won't work. I had not taken care for repeated characters and I adjusted the algorithm accordingly. Probably, wasn't the cleanest solution, as he seemed to be expecting some more improvisation in it. (Later I checked that though the algorithm started correctly, there are faster ways to find the solution if we start comparing the characters from both the ends of strings. For str2, by 'ends'  means taking 1st char from str1 and finding its 1st occurrence in str2 and then continuing with comparison from both the ends).

Anyways, there are other ways to solve this and am not sure if they were expecting other solutions or the same with some improvements.

Then they said that they were done with their questions and that I can leave. They offered me chocolate which were kept on the table in a tray. I wished good day to them and left.

It lasted for around 18-20 minutes (I checked the time before going in and after coming out 😛 , though the duration of interview has no relation to selection or rejection).

There were positives as well as negatives in my interview. I gave myself 60-70% chance probably because of the way the interview started and few laughs they had, and based on the solution to last question.

After my performance in Gate-19, this was the last chance I had, to get into one of the institutes of my choice. The result was declared on 18th, the 5th day after the interview. I logged in to the portal and saw a “Yes” in the “Interview selection” tab. Elation!!!

I would just say to "fight till the end". Even though I had messed up my Gate, I knew I was better. But that's another struggle. I would limit this post to PGEE and IIIT-H.

Thank you.

I had applied for both CDS and CSA M. Tech. Research and got called for both. As I could not clear written exams of IITH, IITG, and programming test at IITB, I wasn’t sure about IISc too.

Interviews were conducted over a period of 5 days from 20th May to 24th May. My interview dates were

21st May: CDS (afternoon session)

22nd May: CSA (morning session)

I reached the campus in the morning at 5:30 am. I had to wait up to 1 pm. Till then I roamed the campus 😊

Test started at around 1:30 pm. I shook my head on seeing all the 5 questions. I was able to attempt just 2 with confidence. I had doubts for the 3rd one and other 2 I knew that I did wrong. In all, I totally messed up with the test and as a result, I was shown the exit door. 

Depressed after the CDS test I went to Yeshwantpur to get a room. One of my friends was coming to stay with me. He had his interviews on the next 2 days. Did some rest and then revised my notes to be prepared for the next day. 

CSA had 3 choices of stream – Theory, Systems, and Intelligent Systems. Each stream had some background subjects. I had prepared for Intelligent Systems, which had Linear Algebra and Probability Theory as background subjects. 

The test was scheduled at 9 am. Reached the campus by 7:30 am. Did breakfast at Prakruthi. Entered the exam hall at around 8:20. We had to select a pool before the test. Each pool had particularly designed tests. Test started at 9 am. It contained 10 questions based on probability and linear algebra. All questions were simple. I had doubts about two questions. Results were announced within 20 mins. Two groups of 7 each were selected from 17-18 candidates for intelligent system pool. I was called at 4^th in group one. I don’t know why called in two separate groups.

The interview started at around 10 am. I got called at around 11:30 am. Went inside. Initially nervous a bit. The panel consisted of 3 professors. 

Prof 1: Told me to sit down, while he went to erase the whiteboard.

Me: Thank you sir

Prof 2: Why did you give the highest preference to Astronomy and Astrophysics? It’s really interesting!

(meanwhile, prof 1 joining in the conversation)

Me: (In a complete surprise!) What sir? I didn’t. It must be a mistake.

(Both professors laughed and the atmosphere got lighten.)

Prof 2: Okay, so you did your BTech from Panjab Unversity.

Me: Yes sir.

Prof 2: What’s your cgpa?

Me: 7.13 sir.

Prof 2: You gave Gate 3 times (saying this he read out each of my scores), 432, 473, 692. It’s a quadratic function!

Me: Yes sir (In my mind – nice observation!)

(All this took nearly 4-5 mins)

Prof 2: So Ravi shall we start with Linear Algebra?

Me: Sure sir.

Prof 1: (Signaled me to go to the board) Take a matrix A of size m $\times$ n. What will be the size of $A^{T}$

Me: Told him.

Prof 1: What will be the size of $A^{T}A$?

Me: Told.

Prof 1: Will it be a symmetric matrix?

Me: Yes sir

Prof 1: How? Can you prove it?

Me: (I knew this but at that moment I couldn’t recall) Sorry sir I’m not getting there.

Prof 1: (He sensed the difficulty and asked) What’s the property of a symmetric matrix?

Me: This question was enough to remind me of everything. Did the proof.

Prof 1: If A is a real matrix then eigenvalues of $A^{T}A$ will be real or imaginary?

Me: Real

Prof 1: Take $AA^{T}$ and specify its size.

Me: Wrote on board.

Prof 1: If m > n then will the eigenvalues of $AA^{T}$ be a subset of eigenvalues of $A^{T}A$?

Me: (Didn’t know anything about it, Tried something but couldn’t progress.) Sorry sir, I don’t know this.

Prof 2: What is a random variable?

Me: Explained.

Prof 2: Suppose a coin is tossed. How will you use random variable?

Me: (After thinking for a while) Let X be a random variable that takes value head or tail (wrong)

Prof 2: What type of values a random variable can take?

Me: Numerical. (Oh! then I corrected my previous answer) Let X denote no. of heads i.e. either X = 0 or 1

Prof 2: What distribution does it follow?

Me: Bernoulli distribution

Prof 2: If the probability of Head is ‘p’ then what are the probabilities of X=0 and X=1?

Me: Answered.

Prof 2: Now if the coin is tossed twice then what values can X take?

Me: (Struggled a bit but finally got it) 3 values 0, 1, and 2

Prof 2: Write probabilities for each of the values of the random variable.

Me: Wrote.

Prof 2: What distribution does it follow?

Me: N number of bernoulli trials is binomial distribution. Here N = 2.

Prof 2: Okay, you can go now

Me: Ok sir, thank you!

Total time of the interview was around 15-20 mins. I could not answer one question. I had made my mind that here also I may not get selected. But still, I hoped for positive response.

5^th June was the happiest day of my life – got the offer letter

Rank – 888

Score – 692

Thank you for your patience! I hope it is helpful for future aspirants