Rishabh Instruments Limited Executive Research Development Interview Questions and Answers

Round: Test
Experience: • 1 question was on time complexity of searching an unsorted array.
• 2 questions were on recursion, ie, number of recursive calls.
• 1 question on analysing given function on string.
• 1 question was on probability(Two hotels, say A and B. Probability of moving from A to B is 2/3, staying at A is 1/3. Probability of moving from B to A and staying at B is 1/2. If they make decisions each hour, and if they were at A at 7:00 pm, what is the probability that they will be at B at 10:00 pm).
• If a set has elements {1,2,3,4 .... n}. Then what is the sum of elements of it's power set. (Ex: S = {1,2}. Then power set is {{},{1},{2},{1,2}}. The sum is 6.
• If a set has elements {1,2,3,4,5,6,7,8,9,10}. Then how many subsets of 3 elements has no consecutive elements.
• 1 question was on designing a DFA for a string starting with a and ending with c and has at least b in it.
• 1 question had machine instructions. We had to find out minimum number of cycles needed to execute the given set of instructions. (a) If the instructions are executed in the given order. (b) If the instructions are executed in random order.
• 1 puzzle on bridges.

Tips: In this round they not only see the answer. They also verify how you approached(So, give correct explanation to your answers).
Duration: 90 minutes
Total Questions: 10

Round: Coding Round
Experience: Two questions were there. 3 hours duration.

1. Long question, I don't remember fully. I'll just give input/output examples. It was basically on string decoding. If jon2snow3 is there the decoded string will be jonjonsnowjonjonsnowjonjonsnow. Given a string and an integer k we have print the kth character in the decoded string
input:
jon2snow3
8
output:
n

2. Given an array and an integer k return the number of contiguous sub arrays whose sum is divisible by k.
input format:
n k

input:
4 5
10 0 4 5

output:
4

explaination: {10},{0},{10,0},{5} are the sub arrays with sum divisible by 5.


Tips: You will have lots of time, so try to optimise the solution if you can. Remember here also they review each individual's code.

Round: Technical Interview
Experience: They will help you a lot if you are stuck at some point in the question. You have to be smart enough to grasp the clue.
Tips: They only ask questions only on data structures and algorithms.

Skill Tips: You have to be strong in coding. Algorithm questions will be mostly on dynamic programming. Data structures questions are mostly on trees.
Skills: C Programming, Maths(esp Probability), Algorithms And Data Structures
Duration: 5
College Name: JSS Mahavidyapeetha Sri Jayachamarajendra College Of Engineering, Mysore