20+ ABIL Group Interview Questions and Answers

Count the number of subarrays whose combined strength matches the given enemy strength.

• Iterate through all subarrays and calculate their sum to check if it matches the enemy strength.

• Use two pointers technique to efficiently find subarrays with sum equal to the enemy strength.

• Consider edge cases like when the enemy strength is 0 or when all elements in the array are equal to the enemy strength.

Move all zeroes to the end of an unsorted array while maintaining the order of non-zero elements.

• Iterate through the array and maintain two pointers - one for non-zero elements and one for zeroes.

• Swap non-zero elements with zeroes to move zeroes to the end of the array.

• Maintain the relative order of non-zero elements while moving zeroes to the end.

Swap two numbers without using a temporary variable.

• Use bitwise XOR operation to swap the values of X and Y without using a temporary variable.

• The XOR operation works by toggling the bits of the numbers.

• Example: X = 10, Y = 20. X = X XOR Y, Y = X XOR Y, X = X XOR Y. After swapping, X = 20, Y = 10.

Implement Merge Sort algorithm to sort a sequence of numbers in non-descending order.

• Divide the input array into two halves recursively until each array has only one element

• Merge the sorted halves to produce a completely sorted array

• Time complexity of Merge Sort is O(n log n)

• Example: Input: [3, 1, 4, 1, 5], Output: [1, 1, 3, 4, 5]

DFS traversal to find connected components in an undirected and disconnected graph.

• Use Depth First Search (DFS) algorithm to traverse the graph and find connected components.

• Maintain a visited array to keep track of visited vertices.

• For each unvisited vertex, perform DFS to explore all connected vertices and form a connected component.

• Repeat the process until all vertices are visited and print the connected components.

Determine the minimum number of platforms needed at a railway station so that no train has to wait.

• Sort the arrival and departure times arrays in ascending order.

• Use two pointers to iterate through the arrays and keep track of the number of platforms needed.

• Increment the number of platforms needed when a train arrives and decrement when a train departs.

• Return the maximum number of platforms needed at any point.

Create base class Shape with field shapeType and method printMyType. Implement Square and Rectangle classes with calculateArea method.

• Create a base class Shape with shapeType field and printMyType method.

• Implement Square and Rectangle classes inheriting from Shape.

• Include additional fields and methods in Square and Rectangle classes.

• Override printMyType method in Square and Rectangle classes to output their respective types.

• Ensure proper encapsulation and validation of length...read more

Given two strings, find uncommon characters in lexicographical order.

• Iterate through each character in both strings and keep track of their frequency using a hashmap.

• Iterate through the hashmap and add characters with frequency 1 to the result list.

• Sort the result list in lexicographical order and return it as the final output.

Remove duplicates from an array while maintaining order.

• Use a set to keep track of unique elements.

• Iterate through the array and add elements to the set if not already present.

• Convert the set back to an array to maintain order.

A deadlock is a situation in which two or more processes are unable to proceed because each is waiting for the other to release a resource.

• Deadlock occurs when processes have acquired resources and are waiting for additional resources that are held by other processes.

• Four necessary conditions for deadlock are mutual exclusion, hold and wait, no preemption, and circular wait.

• Solutions to deadlock include prevention, avoidance, detection, and recovery.

• Prevention involves ensuri...read more

A friend function in OOP is a function that is not a member of a class but has access to its private and protected members.

• Friend functions are declared inside a class with the 'friend' keyword.

• They can access private and protected members of the class.

• They are not member functions of the class, but have the same access rights as member functions.

• Friend functions are often used for operator overloading or to allow external functions to access private members of a class.

C is a procedural programming language while C++ is an object-oriented programming language with features like classes and inheritance.

• C is a procedural programming language, while C++ is a multi-paradigm language with support for object-oriented programming.

• C does not support classes and objects, while C++ does.

• C does not have features like inheritance and polymorphism, which are present in C++.

• C is a subset of C++, meaning that all valid C programs are also valid C++ progra...read more

Multithreading allows for concurrent execution of tasks, improving performance and responsiveness.

• Improved performance by utilizing multiple CPU cores efficiently

• Enhanced responsiveness as tasks can run concurrently without blocking each other

• Better resource utilization by allowing tasks to be executed in parallel

• Facilitates easier handling of complex tasks by breaking them into smaller threads

• Examples: Web servers handling multiple requests simultaneously, video games render...read more

The minimum number of coins to reach a target amount can be calculated using dynamic programming.

• Use dynamic programming to calculate the minimum number of coins needed to reach the target amount.

• Start by initializing an array to store the minimum number of coins needed for each amount from 0 to the target amount.

• Iterate through the coin denominations and update the minimum number of coins needed for each amount based on the current coin denomination.

Elements can be inserted at the back of the queue and deleted from the front.

• To insert an element, use the 'enqueue' operation to add it to the back of the queue.

• To delete an element, use the 'dequeue' operation to remove it from the front of the queue.

• Insertion and deletion operations in a queue have a time complexity of O(1).

Process synchronization is the coordination of multiple processes to ensure they do not interfere with each other while accessing shared resources.

• Preventing race conditions by using synchronization mechanisms like locks, semaphores, and monitors

• Ensuring mutual exclusion to prevent multiple processes from accessing shared resources simultaneously

• Implementing synchronization to maintain the order of execution and avoid deadlocks

• Examples include producer-consumer problem, reade...read more

To find number of nodes in a tree, perform a depth-first or breadth-first traversal and count the nodes. Time complexity is O(n).

• Perform a depth-first or breadth-first traversal of the tree

• Count the nodes as you traverse the tree

• Time complexity is O(n) where n is the number of nodes in the tree

Abstraction is the concept of hiding complex implementation details and showing only the necessary information.

• Abstraction allows developers to focus on the essential features of an object or system.

• It helps in reducing complexity and improving efficiency in software development.

• Implement abstraction in programming by using abstract classes and interfaces.

• Example: In a car, we don't need to know the internal workings of the engine to drive it.

• Example: In programming, a shape ...read more

Function overriding is when a subclass provides a specific implementation of a method that is already provided by its parent class.

• Occurs in inheritance when a subclass has a method with the same name and parameters as a method in its superclass

• The method in the subclass overrides the method in the superclass

• Used to achieve runtime polymorphism in object-oriented programming

• Example: class Animal { void sound() { System.out.println('Animal sound'); } } class Dog extends Animal...read more