Tekion Interview Questions and Answers

Design a notification service for sending alerts to users.

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

• Implement a user subscription system to allow users to choose which notifications they want to receive.

• Include different channels for notifications such as email, SMS, and push notifications.

• Consider implementing a scheduling system to send notifications at specific tim...read more

Detecting cycles in a linked list can be efficiently done using Floyd's Tortoise and Hare algorithm.

• Use two pointers: slow and fast. Slow moves one step, fast moves two steps.

• If there's a cycle, the fast pointer will eventually meet the slow pointer.

• If the fast pointer reaches the end (null), there is no cycle.

• Example: For a list 1 -> 2 -> 3 -> 4 -> 2 (cycle back to 2), slow and fast will meet at 2.

Progress bar in React can be designed using CSS and state management.

• Use CSS to style the progress bar

• Use state management to update the progress value dynamically

• Consider using libraries like react-progress-bar to simplify implementation

In React JS, timers can be implemented using setInterval or setTimeout functions.

• Use setInterval for recurring timers

• Use setTimeout for one-time timers

• Remember to clear the timer using clearInterval or clearTimeout when component unmounts

Use sorting or heap data structure to find top k elements in an array.

• Sort the array in descending order and return the first k elements.

• Use a max heap data structure to efficiently find the top k elements.

• Time complexity can be O(n log n) for sorting or O(n log k) for heap method.

Arrow functions are concise and have implicit return, while normal functions have more flexibility and can be named.

• Arrow functions are written with a concise syntax using '=>'

• Arrow functions do not have their own 'this' keyword

• Normal functions can be named and have more flexibility in terms of syntax and behavior

ES6 updates refer to the new features and syntax improvements introduced in ECMAScript 6, also known as ES2015.

• Arrow functions for more concise syntax

• Let and const for block-scoped variables

• Classes for object-oriented programming

• Template literals for easier string interpolation

• Destructuring assignment for extracting values from arrays and objects

• Spread and rest operators for easier manipulation of arrays and objects

Event loop is a mechanism in JavaScript that allows for asynchronous operations to be executed in a non-blocking way.

• Event loop continuously checks the call stack for any functions that need to be executed.

• If the call stack is empty, the event loop checks the callback queue for any pending tasks.

• Event loop moves tasks from the callback queue to the call stack for execution.

• Example: setTimeout function in JavaScript use...read more

Design a system for booking airplane tickets efficiently and securely.

• Create a user-friendly interface for customers to search and book flights.

• Implement a secure payment system for processing transactions.

• Include features for managing flight schedules, seat availability, and pricing.

• Integrate with airlines' reservation systems for real-time updates.

• Provide options for seat selection, meal preferences, and special requ...read more

High-Level Design (HLD) outlines the architecture and components of our current software system.

• System Architecture: Microservices architecture with independent services for user management, order processing, and payment.

• Data Flow: User requests are routed through an API Gateway to respective microservices, ensuring scalability.

• Database Design: Each microservice has its own database, e.g., PostgreSQL for user data and ...read more

Design a system for searching and booking train tickets on IRCTC, focusing on user experience and backend architecture.

• User Interface: A clean, intuitive UI for searching trains by source, destination, and date.

• Search Algorithm: Implement efficient algorithms to fetch available trains based on user input.

• Database Design: Use a relational database to store train schedules, bookings, and user data.

• Caching: Implement cach...read more

Current system is a web-based application for managing customer data and orders.

• Frontend built with React for user interface

• Backend built with Node.js and Express for server-side logic

• Database using MySQL for storing customer data and orders

• Authentication using JWT tokens for secure access

A polyfill for Promise.all that resolves multiple promises and returns a single promise with an array of results.

• Create a function named 'promiseAll' that accepts an array of promises.

• Use 'Promise.resolve()' to handle non-promise values.

• Utilize 'Promise.allSettled()' to wait for all promises to settle.

• Return a single promise that resolves with an array of results.

Debouncing is a technique to limit the rate at which a function is executed, improving performance in React applications.

• Debouncing delays the execution of a function until after a specified wait time has elapsed since the last time it was invoked.

• Commonly used in scenarios like search input fields to prevent excessive API calls while the user is typing.

• Example: Using lodash's debounce function: const debouncedFunction...read more