Recent posts in Interview Experience

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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

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hey guys,i have just written a post(or tried to write :D) on my IITM experience

REad it here

https://uddiptab.wordpress.com/blog/

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Interview question of IIT Hyderabad, second round of interview held on 25th July, 2016.

Asked about the favorite subjects.

1. Difference between Flow control and condition control.
2. In a network, every node Ni, has buffer capacity of Ci. What is the maximum number of packets that can be transfered in the network at a any time 't'?
3
. Almost Shortest Path Algorithm :
    Statement: Commuters check application to find the best route from point A to B. Since, everyone will use the road, it gets congested which leads to delay. Hence, find possible solution to solve this problem.
    (Hint: Modification of Dijkstra's algorithm )
4. A set of characters are given, find the possible words from this set that has a meaning(ie. Dictionary entry)? Propose data structures for storing Dictionary.
5. Best algorithms for Sorting and difference between Merge, Quick and Heap Sort.
6. Propose a sorting algorithm with complexity of O(n).

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Part - I (Algorithms, DS, Automata, Engg. Maths) & Part - II(Systems - OS, Networks, COA, Compilers, DBMS)

1. Give the tightest  Asymtotic Notation for the recurrence : T(n) = T(n^1/2) + O(1) -
2. There are 16072016 users in Facebook. A graph is formed where an edge(u,v) is defined when a male is friend to a female and vice versa. Estimate the number of simple cycle of length 1607 formed in the graph?
3. If p is a prime number and 0<= a <= p^1/2, find a^((p^2)+1) mod p ?
4. There does not exists a pushdown automata for language L. Which of the following are correct:
   a. TM does not exist
   b. TM exits
   c. DFA exists
   d. NFA does not exists
5. There are 3 processes with CPU times of 15, 12 and 5 ms each which arrive at 0, 5 and 8 ms respectively. Scheduler uses Shortest remaining time first scheduling algorithm. Which processes finish first to last?
6. For Fibonnaci numbers, F(n) = F(n-1) + F(n-2) which of the following are correct :
   a. Iterative solution has an exponential time complexity
   b. Iterative solution has a linear time complexity on n
   c. Iterative solution has a linear time complexity on input size
   d. Recursive solution has exponential complexity
7. There are two sorted arrays of size n each having distinct elements. What is the maximum no. of comparisons req. in the worst case?
8. | a a2 a3 || b b2 b3 || c c2 c3 | matrix is non invertible (where a,b,c are non-negative integers) if and only if
9. In Huffman Coding, there are 4 characters with frequencies as 1, 0.5, 0.25 and 0.25. Average number of bits for encoding these characters?
10. Question on basics of DAG.

1. A floating point number is represented with 36 bits. The exponent is 8 bits plus a sign bit. The remaining bits consists of the mantissa including the sign bit. -32.25 decimal value is represented in floating point Normalized format(leading 1 is missing). Write the bitwise value of the EXPONENT part?
2. Page Fault for a series of pages when there are only 3 physical pages available using OPT replacement algorithm.
3. 255.255.255.240 is subnet mask, what is the maximum number of hosts allowed in the subnet?
4. Order of operations in Compiler ? (Lexical analysis, sematic, syntax .... machine code generation)
5. A processor has 6 stages of a pipeline with S1, S2, S3, S4, S5, S6. Maximum frequency of the processor is 2 GHz. S4 takes the longest amount of time to complete. What is the latency time?
6. There are 100 processes that can run concurrent.Each process requires 1KB of physical memory. Page Size is 64 B. Page table entries take 16 bits. What is the total amount of memory(in Bytes) required to store the page tables?
7. precondition and postcondition : (precondition) x <-x +5, y <- x - y, x <- x+y (postcondition :(x==15 and y==5)), what is the precondition?
8. Counting semaphore has value 10, wait and signal have there usual meanings. How many processes can concurrently access the critical section?
9. There are Insert and Retrieve_Max operations on a set {}. for n such operations what is the time complexity of the efficient algorithm possible?
   a. n^2  b. nlogn   c. n   d. logn
10. There are 3 processes with run time 10,20 and 30. All arrive at 0. Scheduler knows the time taken for each. What is the avg waiting time for the processes?

Programming Test:
1. Implement a^b mod m where a,b and m can be huge. (Hint : O(log n))
2. Ms. Dany wants to clean the house having many rooms. She moves from one room to the next which takes 1 time unit. Each room has only one exit door. After some time she is bound to reach a room which she has cleaned already. Let the time taken to reach the already traversed room be 't' from the start. After that shes enters a cycle, let the length in the cycle be 'k'. Print 't' and 'k'.(do not condiser time taken to clean the room) (Hint : DFS)
3. Longest Increasing Subsequence with the help of 1-D array for dynamic programming. (Hint : MaxTill 1-D array)
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This post is a recollection of questions asked at IIT Kanpur Admission Test Mtech (CSE) 2016. (NOT COMPLETE, but quite many) Thanks Govind Gopakumar :)

Date of Exam: 7th May
Duration: 2 hours Objective + 2 hours Programming Test + 2 hours Subjective (Syllabus at the end)

When you clear first 2 tests, you get called for last. Some 120 people cleared from about 250 for subjective test (AFAIR)


Objective consisted of:  Fill in the gaps, MCQ, one liners (MCQs had negative marking, multiple choices could be right)


Objective:

  1. Theory
     
    1. Height of balanced tree, given the number of nodes.
       
    2. Number of distinct BFS, DFS trees in a graph where any pair of vertices is connected.
       
    3. Solution of $T(n) = T \left ( \sqrt n \right ) + 1$
       
    4. Expression for reachability matrix, given original matrix $A$ and initial reachability matrix $R$
      Also complexity of algorithm it will require.
       
    5. Find remainder: $2^{202} \mod 101$
       
    6. Which of following sets is bijection to set of natural numbers (or Integers maybe)
      $\Bigl ( \mathbb{Z}^{101} \Bigr ),  \Bigl ( \mathbb{Z} \times \mathbb{Q} \Bigr ), \Bigl ( \mathbb{Z} \times \mathbb{R} \Bigr ), \Bigl ( \mathbb{R}^2 \Bigr )$
       
    7. $\begin{align}S &\to aS \mid B \\ B &\to bB \mid \varepsilon \end{align}$
      Which of the following languages is generated?
      (Don't expect me to remember options too eh :D )
       
    8. Which of following languages doesn't have consecutive $b$'s?
      (4 or 5 regular language descriptions were given)
       
    9. Problem related to finding cycle in directed graph (Doubtful)
       
    10. A problem on randomized algorithms (Doubtful, didn't understand)
       
  2. Systems (Some taken from Govind Gopakumar's fb post):
     
    1. UNIX Commands were asked: Searching for file name (kind of)
      Linux command to list all files with a particular keyword in a directory above the current one.
       
    2. DBMS:  Question on performing joins efficiently - best join order - Number of intermediate Queries in best option
       
    3. $32$-bit signed integers - range of integers representable.
       
    4. Diffie-Hellman Key Exchange based on which abstract algebra problem.
       
    5. Problem related to representation of polynomials in Galois Fields (polynomial sum or something)
       
    6. A question on operator forwarding in pipelining (damn it was long, leave for last types :D)
       
    7. A question on operator forwarding in dual issue processors.
       
    8. Virtual Address $\to$ Cache Mapping Question
       
    9. Basic True/False Questions on Virtual Memory.
       
    10. Which segment in Linux process in memory contains information about dynamically linked libraries (something like that)
       
    11. DBMS: $R \Bigl ( \underline{P},  T, U \Bigr )$
      If an index is created on $T$, what will it be called?
      If a further index is created on $U$, what will it be called?
       
    12. Name of function used for integrity in symmetric-key environment.
       
  3. Data Science/ Applications (Didn't attempt this part. Completely ripped off from this post by Govind fb post)
     
    1. Probability question : There are different slots in a day. Batman and Robin can choose at most one slot each to guard (can be same). Different villains choose to attack on different slots (Bane could be defeated only if both Batman and Robin chose this slot). We had to find the probability that 0 villains were defeated, 1 was defeated etc. It had a few tricky cases here and there.
       
    2. Given a channel with one input (0 or 1), and a transition matrix which accounts for error in these inputs, find the entropy of the output. (This was out of syllabus AFAIK)
       
    3. The applications part had really nice questions on probability and linear algebra, mostly logic puzzle kind.

 


Programming Test:

(Partly taken from Govind Gopakumar's Post)

1. Finding number of inversions (find pairs such that i>j but a[i] < a[j].)

2. Checking if row_sum = column_sum for each position in a matrix (Given a grid with coins placed on it, you can take coins from a grid point only if the sum of coins in the point's row matches the sum of coins in the point's column. Find how many coins you can thus obtain. )

3. Calculating Distance values in Edit Distance Problem (Recurrence was provided. Allowed operations: Insert + Delete + Substitution) (Given two strings, find the edit distance between them)

---------------------------   ---------------------------   ---------------------------

Subjective Test:

Again lots of content provided by Govind Gopakumar. The entire Applications part specially :)

I. Theory:

1.  Prove/Disprove:

a) If a graph has k-independent components, it it n-k+1 colorable

b) converse of (a)

c) If a graph is not n-1 colorable, it's a clique

 

2. a) Write O(n) time algorithm to find any cycles in a graph. Print NONE otherwise

b) Prove it's O(n)

 

II. Systems:

1. S is a semaphore.

AddAtomic(Queue* Q1, Queue* Q2)

{

Q1 -> S.wait();

Q2 -> S.wait();

E = Q1 -> dequeue();

Q2 -> enqueue(E);

Q2 ->s.signal();

Q1 -> S.signal();

}

 

This is ought to be a code to atomically dequeue an element from Q1, and add to Q2.

a) Find problem with the implementation

b) Implement a correct solution.

 

2. Give one reason why hierarchical multilevel paging is useful

 

3. Page Table Entry => 8B

Page Size => 4 KB

4-level page table

What is the maximum virtual address space possible?

 

III. Data Science/Applications:


1)

a) Define what a convex set is.
b)Consider two sets A and B of elements from a vector space. Define C = A+B as {x+y | for all x in A and y in B, + here denotes vector addition} Prove C is convex or not. (I think a rigorous definition of this is called the minkowski sum)
c) Define C = A-B similarly, prove if convex or not.

2) a) Consider a discrete sample space {L1, L2...}. Write the expression for expected value of this random variable.
b) Consider two random variables X and Y, which are independent. Prove or provide counterexample for E(X and Y) = E(X)*E(Y) (Where E is expected value)

3) Consider a symmetric matrix A. Prove that the eigenvectors corresponding to distinct eigenvalues of this matrix are orthogonal.

4) a)Consider |u| = 5 and |v| = 6 for two vectors u and v. For the matrix u*v', find the matrix norm (show all steps in computation).
b)prove that |A^t| ≤ |A|^t where A is a matrix and the notation denotes matrix norm.

 

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Other Stuff:

1. Needed to do atleast 2/3 parts in objective and subjective part.

2. I think programming part had good weightage (as neither of my objective or subjective were great, though in programming did all of them ;) )

3. You get lots of time, manage it well.

4. Read questions properly.

5. Programming part was in C, take care of string processing, took me lots of time, as I had forgotten :P  ( Long time :D )

6. Don't ask me for answers or clarifications, as (a) I'm out of practice (b) I had written these in a copy after-exam, so don't remember much now. Ask other members or in the group

7. Don't send me an instant friend request as a token of appreciation :D . If you have stuff to ask, you're  welcome though ;)

Everyone who gave the test, is welcome to add/edit/suggest content to this post :)

To Everyone else, Open to Suggestions

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EDIT: Here's another experience  and this one adds some questions in Data Science/Application Part by jagadeesha_kanihal

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Syllabus below:

 

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I was not very much confident about the ISRO examination result but i got shortlisted for the interview. My inerview venue was DOS Staff Housing,Sector 17, Antariksha Vihar,Dwarka, New Delhi. They have asked us to report at 8:00 AM. Then we were asked to wait in the hall. They used to call group of 4 candidate on random order (Specifically it was the strategy to finish all female candidates' interview early). They did document verification and we were asked to wait for the interview. After waiting complete day. My interview started at 7:20 PM.
 
Interview mostly started with my Bio Data(a specific format by ISRO filled by candidates) and favorite subjects.There were approximately 8 ISROians in the panel. Below are the question which were asked to me
  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 )
 
Interview result was not out till i wrote this so I don't know even what are my chances but it was good experience and hope it will help you too :)