90+ Interview Questions and Answers

The task is to partition an array into two subsets such that the absolute difference between subset sums is minimum.

• Iterate through all possible subsets of the array

• Calculate the sum of each subset

• Find the minimum absolute difference between the subset sums

Interfaces define a contract for behavior, while abstract classes provide partial implementation.

• Interfaces only define method signatures, while abstract classes can have both abstract and concrete methods.

• A class can implement multiple interfaces, but can only inherit from one abstract class.

• Interfaces are used for loose coupling and flexibility in design.

• Abstract classes are used for code reuse and to enforce a common implementation among subclasses.

The task is to reverse a given doubly linked list and return the head of the modified list.

• Create three pointers: prev, current, and next.

• Iterate through the linked list and update the next and prev pointers for each node.

• Finally, update the head pointer to the last node visited and return it as the head of the reversed list.

The task is to sort a list of integers based on their frequency of repetition, with the element with the highest frequency first.

• Count the frequency of each element in the list using a dictionary.

• Sort the elements based on their frequency in descending order.

• If two elements have the same frequency, maintain their original order.

• Return the sorted list.

Software Development Cycle is a process of designing, creating, testing, and deploying software.

• The phases of Software Development Cycle are Planning, Analysis, Design, Implementation, Testing, Deployment, and Maintenance.

• Planning involves defining the project scope, goals, and requirements.

• Analysis involves gathering and analyzing user requirements.

• Design involves creating a detailed design of the software.

• Implementation involves writing code and integrating different compon...read more

Stored procedures are used to perform a set of actions, while functions return a single value.

• Stored procedures are precompiled and stored in the database, while functions are compiled at runtime.

• Functions can be used in SQL statements, while stored procedures cannot be used in SQL statements.

• Functions can be called from within stored procedures, but stored procedures cannot be called from within functions.

Virtual keyword is used to declare a method in a base class that can be overridden in a derived class. Override keyword is used in the derived class to override the implementation of the virtual method.

• Virtual keyword is used in the base class to declare a method that can be overridden in the derived class

• Override keyword is used in the derived class to override the implementation of the virtual method

• Virtual methods provide a way for a base class to define a default implemen...read more

Waterfall model is a linear sequential approach to software development.

• Phases: Requirements gathering, Design, Implementation, Testing, Deployment, Maintenance

• Each phase must be completed before moving to the next

• No going back to previous phases

• Documentation is important

• Less flexible than Agile model

SOLID principles are a set of five design principles for writing maintainable and scalable code.

• Single Responsibility Principle (SRP) - a class should have only one reason to change

• Open-Closed Principle (OCP) - a class should be open for extension but closed for modification

• Liskov Substitution Principle (LSP) - subtypes should be substitutable for their base types

• Interface Segregation Principle (ISP) - clients should not be forced to depend on interfaces they do not use

• Depend...read more

Program to find the second largest element from a 4-digit number

• Convert the number to a string and split it into an array of characters

• Sort the array in descending order

• Return the second element of the array

API testing tool to create and execute collections of requests in Postman

• Postman is a popular API testing tool used to create and execute collections of requests

• Collections are groups of requests that can be organized and executed together

• API testing is done by sending requests to the API and verifying the response

• Postman allows for easy creation and execution of API tests using collections

• To prepare, create a collection of requests and define the necessary variables and envi...read more

Singleton design pattern restricts the instantiation of a class to a single instance and provides a global point of access to it.

• Used when only one instance of a class is required throughout the system

• Provides a global point of access to the instance

• Implemented using a private constructor, static method, and static variable

• Example: Logger class, Database connection class

Developed a predictive model to identify potential customer churn for a telecom company

• Identified key factors contributing to customer churn through exploratory data analysis

• Built a logistic regression model to predict customer churn with 85% accuracy

• Provided actionable insights to the business team to reduce customer churn and improve customer retention

• Implemented the model in production environment using Python and SQL

The question covers topics related to operating systems and database management systems.

• Process scheduling in operating systems involves determining the order in which processes are executed.

• Deadlock refers to a situation where two or more processes are unable to proceed because each is waiting for the other to release a resource.

• Memory management in operating systems involves allocating and managing memory resources for processes.

• Normalization in DBMS is the process of organ...read more

I would follow the standard protocol for handling a dead machine.

• I would first confirm that the machine is indeed dead and not just malfunctioning.

• I would then follow the standard protocol for handling dead machines, which may include checking for any visible damage or signs of wear and tear.

• If necessary, I would consult with other engineers or technical experts to determine the best course of action for repairing or replacing the machine.

• Throughout the process, I would docum...read more

No, C# does not support multiple inheritance.

• C# only supports single inheritance, where a class can inherit from only one base class.

• However, C# does support multiple interface inheritance, where a class can implement multiple interfaces.

• This is achieved using the 'interface' keyword instead of 'class'.

The question covers various testing types, techniques, elements, window handling, frameworks, Cucumber options, hooks, and string manipulation using Java.

• Testing types include functional testing, regression testing, performance testing, etc.

• Testing techniques can involve manual testing, automated testing, black box testing, white box testing, etc.

• Find element is used to locate a single element on a web page, while find elements is used to locate multiple elements.

• Window handl...read more

Routing in MVC is done through the use of routes, which map URLs to controller actions.

• Routes are defined in the RouteConfig.cs file in the App_Start folder

• Routes consist of a URL pattern and a corresponding controller action

• Routes can also include optional parameters and constraints

• Routing is done through the use of the ASP.NET routing engine

• Routing can be customized by creating custom route handlers

Singleton design pattern restricts the instantiation of a class to a single instance and provides a global point of access to it.

• Used when only one instance of a class is required throughout the system

• Provides a global point of access to the instance

• Implemented using a private constructor, static method, and static variable

• Example: Logger class in Java

Professional growth is the continuous development of skills, knowledge, and experience to enhance one's career prospects.

• Acquiring new skills and knowledge through training and education

• Taking on challenging projects and responsibilities

• Networking and building relationships with industry professionals

• Seeking feedback and constructive criticism to improve performance

• Staying up-to-date with industry trends and advancements

• Setting career goals and creating a plan to achieve them

Extension methods are static methods that allow adding new functionality to existing types without modifying the original type.

• Extension methods are defined in a static class.

• They must be declared with the 'this' keyword before the first parameter.

• They can be called as if they were instance methods of the extended type.

• Extension methods can be used to add functionality to built-in types or custom types.

• Example: adding a method to the string type to convert a string to title c...read more

Primary constraints are used to uniquely identify a record while secondary constraints are used to enforce business rules.

• Primary constraints are used to create a unique identifier for a record in a table

• Primary constraints can be used to enforce referential integrity

• Secondary constraints are used to enforce business rules

• Secondary constraints can be used to limit the values that can be entered into a column

Filters in MVC are used to intercept and modify HTTP requests and responses.

• Filters can be used to implement authentication and authorization.

• They can also be used for caching and logging.

• Examples of filters include AuthorizationFilter, ActionFilter, and ExceptionFilter.

Scrum is an agile methodology used for software development and project management.

• It involves iterative and incremental development.

• A team works on a project in sprints, typically 2-4 weeks long.

• The team has daily stand-up meetings to discuss progress and plan for the day.

• The product owner prioritizes the backlog of work.

• At the end of each sprint, a review and retrospective are held to evaluate progress and plan for the next sprint.

Indexes in SQL are used to improve the performance of queries by allowing faster data retrieval.

• Indexes are created on one or more columns of a table.

• They work like a book index, allowing the database to quickly find the data.

• Indexes can be clustered or non-clustered.

• Clustered indexes determine the physical order of data in a table.

• Non-clustered indexes create a separate structure to store the index data.

• Indexes should be used carefully as they can slow down data modification...read more

Dependency injection is a design pattern used to remove hard-coded dependencies and make code more modular and testable.

• Dependency injection involves injecting dependencies into a class rather than having the class create them itself.

• This allows for easier testing and swapping out of dependencies.

• There are three types of dependency injection: constructor injection, setter injection, and interface injection.

• Examples of dependency injection frameworks include Spring and Guice.

Agile model is an iterative approach to software development that emphasizes flexibility and customer satisfaction.

• Agile model involves continuous collaboration between cross-functional teams and customers

• It prioritizes working software over comprehensive documentation

• It allows for changes and adjustments to be made throughout the development process

• Examples of agile methodologies include Scrum, Kanban, and Extreme Programming (XP)

Program to calculate diagonal and anti-diagonal sum of a matrix.

• Iterate through the matrix to calculate diagonal and anti-diagonal sums separately.

• For diagonal sum, add elements where row index equals column index.

• For anti-diagonal sum, add elements where row index + column index equals matrix size - 1.

• Example: For a 3x3 matrix, diagonal sum = matrix[0][0] + matrix[1][1] + matrix[2][2]

• Example: For a 3x3 matrix, anti-diagonal sum = matrix[0][2] + matrix[1][1] + matrix[2][0]

Sort an array of strings containing 0, 1, and 2 in one pass

• Use three pointers to keep track of the positions of 0s, 1s, and 2s

• Iterate through the array and swap elements based on their values and the pointers

• At the end of the iteration, the array will be sorted in place

Dependency injection is a design pattern that allows objects to receive dependencies from external sources rather than creating them internally.

• Dependency injection helps to decouple components and make them more reusable and testable.

• There are three types of dependency injection: constructor injection, setter injection, and interface injection.

• Example: Instead of creating a database connection object inside a class, we can inject it from outside.

• Dependency injection framewor...read more

Abstract class can have both abstract and non-abstract methods, while interface can only have abstract methods.

• Abstract class can have constructors, fields, and methods, while interface can only have constants and method signatures.

• A class can extend only one abstract class, but can implement multiple interfaces.

• Abstract classes are used to define a common behavior for subclasses, while interfaces are used to define a contract for classes to implement.

• Example: Abstract class ...read more

Program in C# demonstrating OOPs concepts

• Use classes and objects to demonstrate encapsulation

• Inheritance can be shown by creating a base class and derived classes

• Polymorphism can be illustrated through method overriding or interfaces

• Abstraction can be implemented by hiding internal details and showing only necessary information

Redux is a predictable state container for JavaScript apps.

• Redux is a state management library commonly used with React.

• It helps in managing the state of an application in a predictable way.

• Redux follows a unidirectional data flow architecture.

• Actions are dispatched to update the state through reducers.

• State is stored in a single immutable state tree.

Java program to convert first letter of each word to upper case

• Split the input string into an array of words

• Iterate through each word and capitalize the first letter

• Join the words back together into a single string

Java program to remove duplicate characters from a string

• Create a HashSet to store unique characters

• Iterate through the string and add each character to the HashSet

• Construct a new string by appending characters from the HashSet

Pass by value involves passing a copy of the actual value, while pass by reference involves passing a reference to the actual value.

• Pass by value: actual value is copied and changes made to the copy do not affect the original value

• Pass by reference: reference to the actual value is passed, changes made to the reference affect the original value

• Example: Pass by value - int x = 10; func(x); // x remains 10 after func call

• Example: Pass by reference - int x = 10; func(&x); // x i...read more

To delete a node in a linked list with a given pointer, update the node's value and next pointer to the next node's value and next pointer.

• Set the value of the node to the value of the next node

• Set the next pointer of the node to the next node's next pointer

I am familiar with a variety of technologies including Java, Python, SQL, HTML, CSS, JavaScript, and Git.

• Java

• Python

• SQL

• HTML

• CSS

• JavaScript

• Git

NCR Corporation is a global technology company that provides products and services that enable businesses to connect, interact, and transact with their customers.

• NCR Corporation is headquartered in Atlanta, Georgia.

• It was founded in 1884 as the National Cash Register Company.

• NCR provides software, hardware, and services for industries such as retail, financial services, hospitality, and telecommunications.

• The company is known for its self-service kiosks and ATMs.

• NCR has a pre...read more

Mobile phone usage can have both positive and negative impacts on children depending on how it is used.

• Excessive mobile phone usage can lead to addiction, sleep deprivation, and social isolation.

• However, mobile phones can also be used for educational purposes, staying connected with family and friends, and for emergency situations.

• It is important for parents to monitor their children's mobile phone usage and set limits to ensure a healthy balance.

• Overall, the impact of mobile...read more

I have closed deals in various industries including technology, healthcare, and retail.

• Closed a $100,000 software deal with a tech company

• Secured a partnership with a healthcare provider resulting in a $50,000 contract

• Negotiated a retail distribution deal leading to a 20% increase in sales

Contracts are legally binding agreements between two or more parties outlining the terms and conditions of a business relationship.

• Contracts can be written or verbal, but written contracts are generally preferred for clarity and enforceability.

• Key components of a contract include offer, acceptance, consideration, legality, capacity, and intention.

• Contracts can cover a wide range of agreements, such as sales, services, employment, and partnerships.

• Breach of contract can result...read more

TDD is Test Driven Development and BDD is Behavior Driven Development.

• TDD is a software development process where tests are written before the code.

• BDD is a software development process where tests are written in a natural language that describes the behavior of the system.

• TDD focuses on testing the functionality of individual units of code.

• BDD focuses on testing the behavior of the system as a whole.

• TDD is often associated with unit testing, while BDD is often associated wit...read more

Spring Sleuth is a distributed tracing system for microservices built on top of Spring Cloud.

• Spring Sleuth helps in tracking and monitoring requests as they travel through different microservices.

• It generates unique trace and span IDs for each request to help in correlating logs and metrics.

• Spring Sleuth integrates with Zipkin, a distributed tracing system, to provide visualization of request flows.

• It is commonly used in microservices architectures to troubleshoot performance...read more

NCR Corporation is a global technology company that provides products and services for businesses.

• NCR stands for National Cash Register, originally founded in 1884

• They specialize in self-service kiosks, point-of-sale terminals, ATMs, and software solutions

• NCR serves industries such as retail, hospitality, financial services, and healthcare

Tackling complex situations requires breaking down the problem, seeking input from team members, prioritizing tasks, and staying calm under pressure.

• Break down the problem into smaller, manageable tasks

• Seek input and feedback from team members to gain different perspectives

• Prioritize tasks based on urgency and impact

• Stay calm under pressure and focus on finding solutions

Tata Nano project has both positive and negative impacts.

• Boon: Affordable car for middle-class families

• Curse: Poor safety features and negative perception

• Boon: Boosted Indian automobile industry

• Curse: Failed to meet sales expectations

• Boon or curse depends on perspective and context

View Model Scope determines whether a ViewModel should be scoped to an activity or a fragment.

• View Model scoped to activity: shared between all fragments within the activity

• View Model scoped to fragment: specific to that fragment only

• Use activity scope for data shared across fragments, fragment scope for fragment-specific data

The question is unclear. Please provide more context.

Binary search program code in Python

• Define a function that takes a sorted array and a target value as input

• Initialize two pointers, low and high, to the start and end of the array

• While low is less than or equal to high, calculate mid as (low + high) // 2 and compare array[mid] with target

• If array[mid] is equal to target, return mid

• If array[mid] is less than target, update low to mid + 1

• If array[mid] is greater than target, update high to mid - 1

• If target is not found, return ...read more

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalization involves breaking down data into smaller, more manageable tables

• It helps in reducing data redundancy by storing data in a structured manner

• Normalization ensures data integrity by minimizing data anomalies

• There are different normal forms such as 1NF, 2NF, 3NF, BCNF, etc.

NCR Corporation is a global technology company that provides products and services that enable businesses to connect, interact, and transact with their customers.

• NCR was founded in 1884 and is headquartered in Atlanta, Georgia.

• The company specializes in omni-channel solutions, ATM machines, point-of-sale systems, self-service kiosks, and more.

• NCR serves industries such as retail, hospitality, financial services, and telecommunications.

• NCR has a presence in over 180 countries ...read more

Structure is a user-defined data type that groups related data members, while class is a blueprint for creating objects with data members and member functions.

• Structure is a value type, while class is a reference type

• Structure members are public by default, while class members are private by default

• Structure does not support inheritance, while class supports inheritance

• Example: struct Person { string name; int age; }; class Person { public: string name; int age; };

Logistics involves the management of the flow of goods, information, and resources from the point of origin to the point of consumption.

• Logistics includes transportation, warehousing, inventory management, and distribution.

• It aims to ensure the timely delivery of products to customers while minimizing costs.

• Examples of logistics activities include route planning, order processing, and supply chain optimization.

Reverse a linked list by changing the pointers direction

• Iterate through the linked list and change the direction of pointers

• Use three pointers - prev, current, next to reverse the list

• Update the head of the linked list to the last node after reversing

Print the Fibonacci series

• Use a loop to generate Fibonacci numbers

• Start with 0 and 1, then add the previous two numbers to get the next number

• Repeat this process until reaching the desired length of the series

Loop in a linked list refers to a situation where a node in the list points to a previous node, creating a cycle.

• Check for a loop using Floyd's cycle detection algorithm

• Use two pointers, one moving at twice the speed of the other

• If the two pointers meet at some point, there is a loop

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Types of normalization include 1NF, 2NF, 3NF, BCNF, and 4NF.

• 1NF (First Normal Form) ensures that each column contains atomic values.

• 2NF (Second Normal Form) eliminates partial dependencies by ensuring all non-key attributes are fully functionally dependent on the primary key.

• 3NF (Third Normal Form) eliminates transitive dependencies by ensuring that non-key attributes...read more

Manual testing process involves executing test cases without the use of automation tools.

• Create test cases based on requirements

• Execute test cases manually

• Record test results

• Report defects

• Retest fixed defects

Singleton pattern in NestJS ensures a class has only one instance and provides a global point of access to it.

• Use the @Injectable() decorator to mark a class as a singleton in NestJS.

• Inject the singleton class into other classes using the constructor.

• The instance of the singleton class will be shared across the application.

A framework is a set of guidelines, libraries, and tools used to develop software applications.

• Provides a structure for organizing code

• Offers reusable code and libraries

• Simplifies development process

• Examples: React, Angular, Django