Interview Experience at Rapyuta Robotics

Hi everyone, I am Mihir from NIT TRICHY. Rapyuta Robotics, a startup, visited our college for internship hiring. There were four rounds in total:

1. PPT Presentation

This was the initial round.

2. Round 1 - Written Test

This round consisted of mathematics, probability, algebra, puzzles, matrix-based questions, and other confusing problems. There were also three simple coding questions:

• Sort program in descending order
• Anagram in string
• Armstrong number

The main focus of the written test was on our thought process in mathematics.

3. Round 2 - Behavioral HR Round

This was a typical HR interview where I was asked about my family, previous studies, and my strengths and weaknesses.

4. Round 3 - Technical Round

In this round, the interviewer asked me about my strong topics on my resume, and I mentioned problem-solving in DSA. The questions included:

• A program to check for a leap year.
• A debugging question on the range of a char data type. The interviewer presented the following C++ code and asked me to explain its behavior:

  int main(){
      char a;
      for(a =1 ; a<= 127 ;a++){
          cout<<a<<" ";
      }
      cout<<endl;
  }

  I didn't give the full correct explanation during the interview, but the solution is that this code results in an infinite loop. When a reaches 127 and a++ is executed, for a signed char, it wraps around to -128 due to overflow. Since -128 is still less than or equal to 127, the loop condition remains true, leading to a Time Limit Exceeded (TLE).

• Questions about operating systems, specifically threads, race conditions, critical section problems, and other in-depth questions.

5. Round 4 - Critical Thinking Round

I was given a puzzle to solve. The interviewer explained the concept of an 'invariant' – something that does not change at every step despite changes in the environment (e.g., the total energy in a falling object). Then, the puzzle was presented:

We have a sorted array of numbers from 1 to 100. There's an operation where any element arr[i-1] can swap with arr[i+1]. After some number of operations, can we make this array sorted in decreasing order? I also had to identify the invariant in this problem.

My solution was that an even-sized array can never be sorted in decreasing order because the last indexed number cannot move to the first position. Only odd-sized arrays can be converted to decreasing order. The invariant is that when we perform the operation, values at odd/even indexed positions always remain at odd/even indices before and after the operation.

Unfortunately, I was rejected for the internship after these rounds. I hope this interview experience finds you helpful. Thank you.