30+ Amadasoft Interview Questions and Answers

To handle large size data for infinite scroll, use virtual scrolling, lazy loading, and optimize data fetching/rendering.

• Implement virtual scrolling to render only the visible items on the screen, reducing memory usage and improving performance.

• Use lazy loading to fetch more data as the user scrolls, avoiding loading all data at once.

• Optimize data fetching and rendering by using efficient algorithms and data structures, and minimizing unnecessary operations.

• Consider implement...read more

Kafka is a distributed streaming platform used for building real-time data pipelines and streaming applications.

• Kafka is used for real-time data processing, messaging, and event streaming.

• It provides high-throughput, fault-tolerant, and scalable messaging system.

• Example use case: Implementing a real-time analytics dashboard for monitoring website traffic.

Answering how to remove a character sequence with a particular number from a string.

• Identify the character sequence to be removed

• Use string manipulation functions to remove the sequence

• Repeat until all instances of the sequence are removed

Create a traffic light simulation in react.js with changing colors based on time configuration.

• Use React state to manage the current color of the traffic light

• Set up a timer to change the color of the traffic light at specified intervals

• Use CSS to style the traffic light and different colors for each light

Code to find character at given position after expanding regex string

• Use a regex engine to expand the given regex string

• Find the substring that matches the given position

• Return the character at that position in the substring

Logic to add days to a given date

• Convert date, month, year to a date object

• Use date object's built-in method to add days

• Convert the updated date object back to date, month, year format

Achieve responsive design by using media queries, flexible layouts, and fluid grids.

• Use media queries to adjust styles based on screen size

• Create flexible layouts that adapt to different screen sizes

• Implement fluid grids to ensure content scales proportionally

Garbage collector in Java manages memory allocation and deallocation automatically.

• Garbage collector runs in the background and frees up memory that is no longer in use.

• It uses different algorithms like Mark and Sweep, Copying, and Generational.

• System.gc() can be used to request garbage collection, but it's not guaranteed to run immediately.

• Garbage collector can cause performance issues if not tuned properly.

• Java provides tools like jstat and jvisualvm to monitor and analyze ...read more

Indexing in database is a way to optimize search queries by creating a data structure that allows for faster retrieval of data.

• Indexing involves creating a separate table that contains the indexed columns and their corresponding row locations.

• Indexes can be created on one or multiple columns.

• Indexes can be clustered or non-clustered.

• Examples of indexing include primary keys, foreign keys, and unique constraints.

Program for internal implementation of hash map

• Define a hash function to map keys to indices in an array

• Create an array of linked lists to handle collisions

• Implement methods for adding, removing, and retrieving key-value pairs

• Consider resizing the array when it becomes too full

• Handle edge cases such as null keys or values

Rotate a 2D matrix 90' anticlockwise

• Transpose the matrix

• Reverse each row of the transposed matrix

• Alternatively, swap elements in each row with their corresponding elements in the opposite row

• Time complexity: O(n^2), Space complexity: O(1)

BookMyShow low level design for ticket booking system

• Use microservices architecture for scalability and flexibility

• Implement user authentication and authorization for secure transactions

• Utilize databases for storing user and event information

• Include payment gateway integration for seamless transactions

Design a system for a chat application

• Use WebSocket for real-time communication

• Implement message queuing for reliable message delivery

• Include features like read receipts, typing indicators, and message history

• Design a user-friendly interface with customizable themes and emojis

• Ensure end-to-end encryption for secure communication

Transpose of a square matrix

• Iterate through each row and column of the matrix

• Swap the elements at (i,j) and (j,i) positions

• Return the transposed matrix

Implement language change functionality using useContext and useReducer

• Create a LanguageContext to store the current language state

• Use useReducer to handle state changes for language selection

• Dispatch actions to update the language state based on user selection

Design a notification service for sending real-time alerts to users.

• Use a scalable messaging system like Kafka or RabbitMQ to handle high volume of notifications.

• Implement a user preference system to allow users to choose their preferred notification channels (email, SMS, push notifications, etc).

• Include a scheduling feature to send notifications at specific times or intervals.

• Ensure notifications are personalized and relevant to each user based on their activity or preferenc...read more

Polyfills are used to provide fallback support for older browsers that do not support certain JavaScript methods like map, reduce, call, and apply.

• Polyfills are JavaScript code that replicate the functionality of newer features in older browsers.

• They are commonly used for methods like map, reduce, call, and apply which may not be supported in all browsers.

• For example, a polyfill for the map method would involve iterating over an array and applying a function to each element.

• P...read more

Segregate numbers in an array of strings based on odd/even

• Iterate through the array and separate odd and even numbers into two separate arrays

• Use parseInt() to convert strings to numbers for comparison

• Return the two arrays of odd and even numbers

Lambda expression is a concise way to represent anonymous functions in Java.

• Lambda expressions were introduced in Java 8.

• They are used to implement functional interfaces.

• They reduce the amount of boilerplate code needed for anonymous classes.

• Syntax: (parameters) -> expression or (parameters) -> { statements; }

• Example: (x, y) -> x + y or (x, y) -> { return x + y; }

Find the second best player among n players.

• Sort the players based on their scores and pick the second highest score.

• If scores are not available, find the second highest rank or position.

• If there are ties for first place, the second best player may be the third or fourth best player.

• If there are ties for second place, there may not be a clear second best player.

Web app optimization techniques focus on improving performance and user experience.

• Minify and compress CSS, JavaScript, and HTML files

• Optimize images and use lazy loading

• Reduce server response time by caching data and using CDNs

• Implement asynchronous loading for non-essential resources

• Use browser caching and enable Gzip compression

Serverside rendering is when the HTML is generated on the server before being sent to the client, while clientside rendering is when the HTML is generated on the client's browser using JavaScript.

• Serverside rendering is better for SEO as search engines can easily crawl the content.

• Clientside rendering can provide a faster initial load time as only data is sent from the server.

• Serverside rendering is more secure as sensitive data is not exposed to the client.

• Clientside renderi...read more

Microservices allow for modular and scalable architecture, while monolithic architecture is simpler but less flexible.

• Microservices break down applications into smaller, independent services that communicate through APIs.

• Monolithic architecture involves building the entire application as a single unit, making it easier to develop but harder to scale.

• Microservices offer better fault isolation and scalability, while monolithic architecture is easier to deploy and manage.

• Example...read more

Rain water trapping problem involves calculating the amount of rainwater that can be trapped between buildings.

• Calculate the maximum height of water that can be trapped at each index

• Calculate the water trapped at each index by subtracting the height of the building at that index

• Sum up the water trapped at each index to get the total amount of rainwater trapped

Streams in Java are a sequence of elements that can be processed in parallel or sequentially.

• Streams are used to perform operations on collections of data.

• They can be used to filter, map, reduce, and sort data.

• Streams can be processed in parallel to improve performance.

• Examples include using streams to filter a list of names or map a list of numbers to their squares.

Indexing can lead to increased storage requirements and slower write performance.

• Indexing can increase the size of the database as additional data structures are created to support the index.

• Indexes can slow down write operations as the database must update both the data and the index.

• Indexes can become fragmented over time, leading to decreased performance.

• Indexes can also lead to increased memory usage and CPU overhead.

• In some cases, indexing may not be necessary or may eve...read more

Explanation of OOP concepts with framework

• OOP concepts include encapsulation, inheritance, and polymorphism

• Encapsulation allows bundling of data and methods into a single unit

• Inheritance enables the creation of new classes based on existing ones

• Polymorphism allows objects of different classes to be treated as the same type

• Frameworks provide a structure and set of tools for developing software applications

• Frameworks often implement OOP principles to provide reusable components...read more

LRU cache is a data structure that stores a fixed number of items and removes the least recently used item when the cache is full.

• Use a combination of a doubly linked list and a hashmap to implement the LRU cache.

• When an item is accessed, move it to the front of the linked list to mark it as the most recently used item.

• When adding a new item, check if the cache is full. If it is full, remove the least recently used item from the end of the linked list.

• Use a hashmap to store t...read more

Design a movie ticket system

• Create a database to store movie details, showtimes, and seat availability

• Implement a user interface for customers to select movies, seats, and purchase tickets

• Develop a ticketing algorithm to handle seat reservations and prevent double bookings

• Include features like seat selection, payment processing, and ticket confirmation

• Consider scalability and performance for handling high traffic during peak times

HLD (High-Level Design) and LLD (Low-Level Design) are two stages in software design process.

• HLD focuses on system architecture and overall design.

• LLD focuses on detailed design of individual components.

• HLD defines the structure and behavior of the system.

• LLD defines the implementation details of each component.

• HLD is more abstract and conceptual.

• LLD is more concrete and specific.

• HLD helps in understanding the system's functionality and interactions.

• LLD helps in understanding...read more

Custom hook for debouncing user input in React applications

• Accepts a value and delay as arguments

• Uses useEffect to set a timeout to update the debounced value after the specified delay

• Returns the debounced value and a function to update the input value