Zopper Senior Software Developer Interview Questions and Answers

1. Program on LRU algorithm for pages
2. Multithreading- 3 threads to run one after - use of binary_semaphore
3. Mutex vs Semaphore

Tree based coding problem

Q1. Multithreading and locking mechanism
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Q2. Reverse Linked list code
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Q1. Why do you want to join Greyorange
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Q1. Design a multithreaded logger system
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A multithreaded logger system allows multiple threads to log messages concurrently without blocking each other.
• Use a thread-safe data structure like a concurrent queue to store log messages.

• Implement a logging class with methods for adding log messages and writing them to a file.

• Use synchronization mechanisms like locks or semaphores to ensure thread safety.

• Consider using a separate thread for writing log messages to t...read more
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Q2. How virtual pointers work?
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Virtual pointers are used in C++ to implement polymorphism by allowing objects to be accessed through a base class pointer.
• Virtual pointers are used in C++ to achieve runtime polymorphism.

• They are created by adding virtual keyword to a function in a base class.

• Virtual pointers allow objects of derived classes to be accessed through a base class pointer.
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Q1. Basic to intermediate.net, EF, SQL, C#, OOP
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Q2. Basics of .Net Core
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Q1. Deep into.net and sql
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Three coding problems were asked one was to print frequency of each character in a string, second was also similar to this problem unable to recall it and third problem was given an array of string and range from L to R find the nth character if all strings from L to R is concatenated and sorted. Apart from these three coding problems there were 10 easy MCQ's.

Q1. Basic questions on java and spring boot, annotations, oops concept.
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Q2. Code LRU cache(with no updates), just to implement push and pop operation with given window size of 4.
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Q1. It was a design round where I was asked to write class models of a in memory session management system without using tools like redis.
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Q1. Move negative elements to right side of array
Ans. 
Move negative elements to right side of array
• Iterate through the array and swap negative elements to the right side

• Use two pointers approach to keep track of positive and negative elements

• Maintain the order of elements while moving negatives to the right side
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Medium to hard questions based on arrays, dp

Q1. Quick sort algorithm
Ans. 
Quick sort is a popular sorting algorithm that uses divide and conquer strategy.
• Divides array into smaller sub-arrays based on a pivot element

• Recursively sorts sub-arrays

• Combines sorted sub-arrays to get final sorted array

• Time complexity: O(n log n) on average, O(n^2) worst case

• Example: [3, 6, 8, 10, 1, 2, 1] -> [1, 1, 2, 3, 6, 8, 10]
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Q2. Modified rotate a matrix
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Rotate a matrix by 90 degrees in place
• Transpose the matrix

• Reverse each row of the transposed matrix
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Q1. Java script, React JS
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Q2. Data structures and algorithms
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