20+ Senior Software Interview Questions and Answers

Implement a system to prevent double booking of the same seat in a bookmyshow-like application.

• Implement a locking mechanism to prevent simultaneous booking of the same seat by two users.

• Use a transactional approach to ensure atomicity of seat booking process.

• Display real-time seat availability to users to avoid conflicts.

• Notify users if the seat they are trying to book is no longer available.

• Implement a queue system to handle simultaneous booking requests for the same seat.

Sort an array with letters in ascending and numbers in descending order without using default sort methods.

• Separate letters and numbers into two different arrays. Example: letters = ['a', 'b', 'c', 'd'], numbers = [1, 3, 5, 6].

• Sort the letters array using a simple sorting algorithm like bubble sort or selection sort.

• Sort the numbers array in descending order using a similar sorting algorithm.

• Combine the sorted letters and numbers arrays into the final output format.

Find the smallest substring in s1 that contains all characters from s2.

• Use a sliding window approach to maintain a window of characters in s1.

• Keep a count of characters in s2 using a hash map.

• Expand the window by moving the right pointer and contract it by moving the left pointer when all characters are found.

• Example: s1 = 'ADOBECODEBANC', s2 = 'ABC' -> smallest substring is 'BANC'.

• Check if the current window contains all characters from s2 by comparing counts.

Explanation of concepts with real-life examples

• Abstraction: Using a TV remote without knowing the internal circuitry

• Encapsulation: A car driver only needs to know how to drive, not how the engine works

• Inheritance: A child inheriting traits from their parents

• Polymorphism: A shape can take on different forms, such as a square or a triangle

Service Registry is a centralized directory for managing information about services. Hibernate is an ORM tool for Java. Microservices pattern is an architectural style that structures an application as a collection of loosely coupled services.

• Service Registry is used for service discovery, load balancing, and failover in microservices architecture.

• Hibernate is an ORM tool that maps Java objects to database tables and vice versa, simplifying database interactions.

• Microservices...read more

A URL reputation service assesses the safety and trustworthiness of URLs to prevent malicious activities.

• Utilizes a database of known malicious URLs to check against incoming requests.

• Employs machine learning algorithms to analyze URL patterns and predict potential threats.

• Incorporates user feedback to improve the accuracy of reputation scores over time.

• Can categorize URLs into different risk levels (e.g., safe, suspicious, malicious).

• Integrates with web browsers and security...read more

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

• S - Single Responsibility Principle

• O - Open/Closed Principle

• L - Liskov Substitution Principle

• I - Interface Segregation Principle

• D - Dependency Inversion Principle

Caching in web APIs improves performance by storing frequently accessed data

• Use in-memory caching for fast access to data

• Implement output caching to store responses for future requests

• Consider using distributed caching for scalability

• Set appropriate cache expiration policies to ensure data freshness

Remove repeated letters from a given string

• Iterate through the string and keep track of seen letters

• Use a set to store unique letters and build the result string

MVC Routing is a mechanism to map incoming requests to specific controller actions.

• Routing is used to define URL patterns and map them to specific actions in the controller.

• It helps to create clean and SEO-friendly URLs.

• Routing can also be used to pass parameters to the controller action.

• MVC Routing is a part of the ASP.NET framework.

• Example: RouteConfig.cs file in ASP.NET MVC application defines the routing rules.

Polymorphism is the ability of an object to take on many forms. A real-life example is a vehicle.

• Polymorphism allows a vehicle object to take on different forms such as car, truck, or motorcycle

• Each form has its own unique properties and methods, but they all share common characteristics such as having wheels and an engine

• Polymorphism allows for more efficient and flexible code as it allows for the use of a single class to represent multiple objects

An IIFE (Immediately Invoked Function Expression) is a JavaScript function that runs as soon as it is defined.

• IIFE is defined using function syntax followed by parentheses: (function() { /* code */ })();

• It creates a new scope, preventing variable collisions in the global scope.

• Commonly used for module patterns and encapsulating code.

• Example: (function() { var x = 10; console.log(x); })(); // Outputs 10

• IIFEs can also accept parameters: (function(a, b) { return a + b; })(5, 10)...read more

One disadvantage of the repository pattern is the potential for over-abstraction and complexity.

• Can lead to unnecessary complexity in simple applications

• May result in additional overhead and performance issues

• Difficult to implement complex queries efficiently

• Can lead to code duplication if not properly managed

Event loop is a mechanism in programming that allows for asynchronous execution of code by continuously checking for and handling events.

• Event loop is commonly used in JavaScript to handle asynchronous operations.

• It allows for non-blocking I/O operations by delegating tasks to the operating system.

• Event loop processes events in a queue and executes associated callback functions.

• Example: In Node.js, the event loop allows for handling multiple requests concurrently without bloc...read more

Hoisting is a JavaScript mechanism where variable and function declarations are moved to the top of their containing scope during the compilation phase.

• Variable and function declarations are hoisted to the top of their scope.

• Only declarations are hoisted, not initializations.

• Function declarations take precedence over variable declarations.

• Hoisting can lead to unexpected behavior if not understood properly.

Design a scalable Instagram-like system for photo sharing, user interactions, and social networking.

• User Authentication: Implement OAuth for secure login and registration.

• Photo Upload: Use cloud storage (e.g., AWS S3) for storing images.

• Feed Generation: Create an algorithm to display posts based on user preferences and interactions.

• Comments and Likes: Design a relational database schema to handle likes and comments efficiently.

• User Profiles: Allow users to create and edit pro...read more

An anagrams program checks if two strings are anagrams of each other.

• Create a function that takes in two strings as input

• Remove any spaces and punctuation from the strings

• Convert both strings to lowercase for case-insensitive comparison

• Sort the characters in both strings

• Check if the sorted strings are equal to determine if they are anagrams

Object-oriented programming principles in C# include encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Inheritance: Allowing a class to inherit properties and behavior from another class.

• Polymorphism: Allowing objects to be treated as instances of their parent class.

• Abstraction: Hiding the complex implementation details and showing only the necessary features.