Hello Everyone, I am Ashwin Kulkarni(GATE 2018 Rank 323, Score 759, Fresher) Sharing my Interview experience at IITH for TA programme.

I would suggest every aspirant one thing, please don't stop your revision or study even after getting GATE rank (especially in the range of 200-400) because that confidence and knowledge will be helpful in the Interviews.

IITH interview has mainly 2 stages - Written and then Interview.

*Date - 5th July 2018*

**Written Test - **

We have to answer 3 questions in a written format.

* Question 1:* Let M is n x n matrix, and k is an Integer. You have to write a program which takes input for M and k and computes Mk.

* Answer:* I have written a program where initially it takes input for n x n matrix, then used efficient way of computing Mk as - 1) If K is even then used (M2)k/2 else 2) if k is odd then used M.M(k-1).

But remember M is not just a number its matrix. Hence wrote a function which always does matrix multiplication.

* Question 2: *Take a function n2long - n + 7 and prove

**n2long - n + 7 = O(n2logn).**

* Answer: *Using simple notation rules of

**Big-Oh**I just proved it where

**f(n) $\leq$ c.g(n)**and found values of

**c**and

**n**

* Question 3:* Let

**T**is a tree and

**a,b**are any nodes then find their least common ancestor.

* Answer:* I used a way where initially by traversing and analyzing each node and its children reach up to a and b and save its parent. then check if those parents are same or not otherwise find grandparents of those nodes recursively.

(This test was for an hour and they distributed all students among four panels)

My interview was conducted by panel 1. where 3 professors were present. 1) HOD - **M. V. Panduranga Rao **2)** Srijith P. K. 3) I don't remember sorry :p**

you can check all faculty members here - http://cse.iith.ac.in/?q=People/Faculty

I will use notations as Interviewer 1, 2 or 3.

**Interviewer 1**: Hello Ashwin Tell us your Gate score and Rank.

**Me:** Good Afternoon sir, My Gate score is 759, and rank - 323.

**Interviewer 1:** Kulkarni, Means Maharashtra? Pune? Smiling :p

**Me:** Yes sir, I am from Maharashtra, Aurangabad.

**Interviewer 1:** Okk, Ajantha, Ellora caves, Daultabad fort. :p (Tried to feel me comfortable). So you have mentioned about research paper can you give an idea about it, and about your project?

**Interviewer 2:** Before that, you have given preference as ML, so can we start with Mathematics, Probability?

**Me:** Yes sure sir, (I gave an answer about a simple question on probability) and but sir I filled ML because of its interest and my work on Natural Language Processing, but don't really much confident about it.

**Interviewer 2:** Ok, let's take Linear algebra then. just give us an idea about Eigen Values and vectors (On the board)

**Interviewer 1:** First of all, define vectors, Eigen values and vectors then prove its equation.

**Me:** (Defined Eigen values and also wrote its equation on the board) then tried to explain each term of it and how we compute (lambda)

**Interviewer 1: (**half satisfied face). Tell us about the rank of a matrix.

**Me:** Told about the rank of matrices.

**Interviewer 2**: You have worked on NLP, then which how you have used this concept tell us broadly about it and which algorithm you have used in Name entity recognition?

**Me:** (told about NLP) Sir, I have used Stanford CoreNLP libraries for the whole process. and through its jar files, I did Name Entity recognition,

**Interviewer 2:** Yes but which algorithm have you used for Name Entity recognition?

**Me:** I directly used libraries so I don't know the internal algorithm so I told them Sorry I don't remember sir.

**Interviewer 2:** Can you tell us about Dynamic Prog? and write the equation of Longest common subsequence algorithm.

**Me:** Wrote the equation and told all the terms of it.

**Interviewer 2:** Let's take two strings XCXX, XCXY then calculate its LCS. (I calculated using Dynamic programming matrix)

After that, they impressed :)

**Interviewer 1:** Okay let's tell us your favorite subjects

**Me:** (Alas! now they asked me :p) I said, sir, I am much confident about DS and Algorithm

**Interviewer 1:** tell the definition of graphs.

**Me:** Graph has a set of nodes and edges (I literally just told this definition without even thinking)

**Interviewer 1:** Okay then tell us the difference between graphs and trees.

**Me:** Trees has n-1 edges (I was somehow upset at this point, and thought I even don't know the basic definition) :p

(That's why I told in the starting of this post don't stop studying after GATE result. because we remember how to solve questions different algorithm, but we forget these simple definitions and terminologies)

**Interviewer 1:** Only n-1 edges is enough? and came to the board and gave me a graph which has 4 nodes but 3 edges and which was not a tree)

**Me: **Ohhk sorry tree should be connected, it should be single connected component.

**Interviewer 1:** You are from Maharashtra, then take Aurangabad, Ellora cave, Ajantha cave and daultabad and some other places as individual nodes. and draw edges between them (He told me to draw an edge from this node to that like) then tell us how I should reach from Aurangabad to Ellora?

**Me:** Using Shortest path Algorithm found the shortest path

**Interviewer 1:** Good, now tell us What is Data structure, is graph a pure data structure?

**Me:**(Messed up and told) data structure is a set which saves the data and we can retrieve whenever we need it. and yes in the graph we save data at each node and edges so it has to be a pure data structure

**Interviewer 1:** are you sure? think about it.

**Me:** I am not totally sure with it sir, but i just thought this way.

**Interviewer 2:** Okay think on it after the interview

(I thought it should be end of my interview :p)

**Interviewer 1:** now do you know hashing functions? hashing?

**Me:** Somehow I gamblled and told something about hashmaps (like key value pairs) then again thinked on it for sometime then gave an informal definition about hashing functions.

**Interviewer 1:** half satisfied. then whats the use of hashing and hash functions, and why its different form array?

**Me:** Actually using hashfunctions we can map many items at one place but in the array we can store one element at a place.

**Interviewer** 1: still place for storing elements is same then what's the advantage?

**Me:** Using hashing we can locate and retrieve the data faster than array in some cases O(1) time.

Interviewer 1 and 2 : okay. you have written on the paper, big Oh as worst case complexity but for what?

**Me:** it's complexity of an algorithm. (They said are you sure?) ohh then I said it's worst case of a function.

**Interviewer 1:** okk, nice talking with you ashwin. We will let you know the result.

**Me:** Okay thankyou sir.

(I wasn't expecting the result will be in my favour, because at the end I messed up somehow)

But on the same day (5th July) on the 7.58pm they sent a mail that I am provisionally selected for MTech CSE TA course at IITH.

I was very happy for cracking an interview in front of those talented young professors.** **