The Kothari Wheels Interview Questions and Answers

Round duration - 70 Minutes
Round difficulty - Medium

There were 5 people in the zoom meet, including me. Rest all 4 were interviewers, 3 from India and 1 from the United Kingdom.
They started with my introduction and then moved on to the questions from my resume, starting with my internship at Samsung Bangalore and then projects.
Then another interviewer asked about my weakness and strength. Then comes the turn of coding questions.
Starting with finding the minimum element in O(1) time, rotating the 2-D array by 90 degrees, OOPS questions were also asked like- polymorphism, abstraction, virtual class. Some OS questions were- cache, paging algorithms.
Then come my POR and other activities.

Q1. 
Kth Smallest Element Problem Statement
You are provided with an array of integers ARR of size N and an integer K. Your task is to find and return the K-th smallest value present in the array. All elements...read more
Ans. 
Find the K-th smallest element in an array of distinct integers.
• Sort the array and return the element at index K-1.

• Use a min-heap to find the K-th smallest element efficiently.

• Implement quickselect algorithm for optimal performance.
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Q2. 
Inplace Rotate Matrix 90 Degrees Anti-Clockwise
You are provided with a square matrix of non-negative integers of size 'N x N'. The task is to rotate this matrix by 90 degrees in an anti-clockwise directi...read more
Ans. 
Rotate a square matrix by 90 degrees anti-clockwise without using extra space.
• Iterate through each layer of the matrix from outer to inner layers

• Swap elements in groups of 4 to rotate the matrix in place

• Handle odd-sized matrices separately by adjusting the loop boundaries
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Q3. What are the page replacement algorithms in Operating Systems?
Ans. 
Page replacement algorithms are used in operating systems to decide which page to replace when a new page needs to be brought in.
• FIFO (First In, First Out) - replaces the oldest page in memory

• LRU (Least Recently Used) - replaces the page that has not been used for the longest time

• LFU (Least Frequently Used) - replaces the page that has been used the least number of times

• Optimal - replaces the page that will not be used
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Q1. It went well, results awaiting
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Q1. Basic questions about your experience and expectations
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A take home assignment

Round duration - 120 minutes
Round difficulty - Hard

There was 2 parts. First part problems were based on Quantitative Aptitude. Problems were of 3 types- Easy, Medium and Hard with different scores. Difficulty keeps on increasing if you answer correctly and keeps on decreasing if you answer incorrectly.
First part was of 45 mins.
Second part consisted of 2 coding problems- Medium, Hard. One was based on Greedy and other was a difficult DP + Bitmask problem.
Coding part had more weightage than Aptitude.

Q1. 
K Centers Selection Problem
In Ninja Land, there are cities numbered from 0 to N-1. The distances between each pair of cities are represented by an N * N matrix 'DIST', where 'DIST[i][j]' is the distance ...read more
Ans. 
The problem involves selecting K cities to install servers in Ninja Land to minimize the maximum distance from any city to a nearest server.
• Iterate through all possible combinations of K cities to select for server installation.

• Calculate the maximum distance from any city to the nearest server for each combination.

• Choose the combination that minimizes the maximum distance.
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Q2. 
Beautiful String Verification
Given a non-empty string inputString, determine if it can be converted into a 'Beautiful String' using the defined operation.
You can perform any number of operations to con...read more
Ans. 
Determine if a given string can be converted into a 'Beautiful String' using a specific operation.
• Check if the input string is already a 'Beautiful String' by checking if it contains 'abc' in the correct positions.

• If 'abc' is present in the input string, check if the left and right portions satisfy the defined conditions.

• If the conditions are met, return 'True', otherwise return 'False'.
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Round duration - 90 minutes
Round difficulty - Medium

There were 3 interviewers in my panel. The most senior panellist asked q. related to my interests and internship experience.
Other 2 asked questions related to Coding and subjects. There was 1 coding question which was implementation based and involved many corner cases. They were checking if I was able to figure out different corner cases and handle those. 
There were situation based questions also asked. One question was on system design of Arogya Setu App.

Q1. 
Complex Number Multiplication
Calculate the product of two complex numbers represented as strings in the form “A+Bi”. Here, ‘A’ represents the real part, and ‘B’ represents the imaginary part.
Explanatio...read more
Ans. 
Calculate the product of two complex numbers represented as strings in the form 'A+Bi'.
• Parse the input strings to extract real and imaginary parts of both complex numbers

• Perform multiplication of the complex numbers using the formula (a+bi)*(c+di) = (ac - bd) + (ad + bc)i

• Format the result as a string in the form 'A+Bi' and return
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Round duration - 30 minutes
Round difficulty - Easy

HR round involved basic questions related to background and behaviour. It was basically a cultural fit round.