Coding Interview Resources
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This channel contains the free resources and solution of coding problems which are usually asked in the interviews.

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Python Interview Questions
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Web Development Roadmap
|
|-- Fundamentals
| |-- Web Basics
| | |-- Internet and HTTP/HTTPS Protocols
| | |-- Domain Names and Hosting
| | |-- Client-Server Architecture
| |
| |-- HTML (HyperText Markup Language)
| | |-- Structure of a Web Page
| | |-- Semantic HTML
| | |-- Forms and Validations
| |
| |-- CSS (Cascading Style Sheets)
| | |-- Selectors and Properties
| | |-- Box Model
| | |-- Responsive Design (Media Queries, Flexbox, Grid)
| | |-- CSS Frameworks (Bootstrap, Tailwind CSS)
| |
| |-- JavaScript (JS)
| | |-- ES6+ Features
| | |-- DOM Manipulation
| | |-- Fetch API and Promises
| | |-- Event Handling
| |
|-- Version Control Systems
| |-- Git Basics
| |-- GitHub/GitLab
| |-- Branching and Merging
|
|-- Front-End Development
| |-- Advanced JavaScript
| | |-- Modules and Classes
| | |-- Error Handling
| | |-- Asynchronous Programming (Async/Await)
| |
| |-- Frameworks and Libraries
| | |-- React (Hooks, Context API)
| | |-- Angular (Components, Services)
| | |-- Vue.js (Directives, Vue Router)
| |
| |-- State Management
| | |-- Redux
| | |-- MobX
| |
|-- Back-End Development
| |-- Server-Side Languages
| | |-- Node.js (Express.js)
| | |-- Python (Django, Flask)
| | |-- PHP (Laravel)
| | |-- Ruby (Ruby on Rails)
| |
| |-- Database Management
| | |-- SQL Databases (MySQL, PostgreSQL)
| | |-- NoSQL Databases (MongoDB, Firebase)
| |
| |-- Authentication and Authorization
| | |-- JWT (JSON Web Tokens)
| | |-- OAuth 2.0
| |
|-- APIs and Microservices
| |-- RESTful APIs
| |-- GraphQL
| |-- API Security (Rate Limiting, CORS)
|
|-- Full-Stack Development
| |-- Integrating Front-End and Back-End
| |-- MERN Stack (MongoDB, Express.js, React, Node.js)
| |-- MEAN Stack (MongoDB, Express.js, Angular, Node.js)
| |-- JAMstack (JavaScript, APIs, Markup)
|
|-- DevOps and Deployment
| |-- Build Tools (Webpack, Vite)
| |-- Containerization (Docker, Kubernetes)
| |-- CI/CD Pipelines (Jenkins, GitHub Actions)
| |-- Cloud Platforms (AWS, Azure, Google Cloud)
| |-- Hosting (Netlify, Vercel, Heroku)
|
|-- Web Performance Optimization
| |-- Minification and Compression
| |-- Lazy Loading
| |-- Code Splitting
| |-- Caching (Service Workers)
|
|-- Web Security
| |-- HTTPS and SSL
| |-- Cross-Site Scripting (XSS)
| |-- SQL Injection Prevention
| |-- Content Security Policy (CSP)
|
|-- Specializations
| |-- Progressive Web Apps (PWAs)
| |-- Single-Page Applications (SPAs)
| |-- Server-Side Rendering (Next.js, Nuxt.js)
| |-- WebAssembly
|
|-- Trends and Advanced Topics
| |-- Web 3.0 and Decentralized Apps (dApps)
| |-- Motion UI and Animations
| |-- AI Integration in Web Apps
| |-- Real-Time Applications

Web Development Resources πŸ‘‡πŸ‘‡

Intro to HTML and CSS

Intro to Backend

Intro to JavaScript

Web Development for Beginners

Object-Oriented JavaScript

Best Web Development Resources

Join @free4unow_backup for more free resources.

ENJOY LEARNING πŸ‘πŸ‘
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List Comprehension in Python
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SQL interview questions with answers πŸ˜„πŸ‘‡

1. Question: What is SQL?

Answer: SQL (Structured Query Language) is a programming language designed for managing and manipulating relational databases. It is used to query, insert, update, and delete data in databases.

2. Question: Differentiate between SQL and MySQL.

Answer: SQL is a language for managing relational databases, while MySQL is an open-source relational database management system (RDBMS) that uses SQL as its language.

3. Question: Explain the difference between INNER JOIN and LEFT JOIN.

Answer: INNER JOIN returns rows when there is a match in both tables, while LEFT JOIN returns all rows from the left table and the matched rows from the right table, filling in with NULLs for non-matching rows.

4. Question: How do you remove duplicate records from a table?

Answer: Use the DISTINCT keyword in a SELECT statement to retrieve unique records. For example: SELECT DISTINCT column1, column2 FROM table;

5. Question: What is a subquery in SQL?

Answer: A subquery is a query nested inside another query. It can be used to retrieve data that will be used in the main query as a condition to further restrict the data to be retrieved.

6. Question: Explain the purpose of the GROUP BY clause.

Answer: The GROUP BY clause is used to group rows that have the same values in specified columns into summary rows, like when using aggregate functions such as COUNT, SUM, AVG, etc.

7. Question: How can you add a new record to a table?

Answer: Use the INSERT INTO statement. For example: INSERT INTO table_name (column1, column2) VALUES (value1, value2);

8. Question: What is the purpose of the HAVING clause?

Answer: The HAVING clause is used in combination with the GROUP BY clause to filter the results of aggregate functions based on a specified condition.

9. Question: Explain the concept of normalization in databases.

Answer: Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. It involves breaking down tables into smaller, related tables.

10. Question: How do you update data in a table in SQL?

Answer: Use the UPDATE statement to modify existing records in a table. For example: UPDATE table_name SET column1 = value1 WHERE condition;

Here is an amazing resources to learn & practice SQL: https://bit.ly/3FxxKPz

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πŸš€ Roadmap to Become a C++ Developer πŸ”°

πŸ“‚ Programming Basics
β€ƒβˆŸπŸ“‚ Master C++ Syntax, Variables & Data Types
β€ƒβ€ƒβˆŸπŸ“‚ Learn Control Flow, Loops & Functions
β€ƒβ€ƒβ€ƒβˆŸπŸ“‚ Practice with Simple Programs

πŸ“‚ Object-Oriented Programming (OOP)
β€ƒβˆŸπŸ“‚ Understand Classes, Objects & Inheritance
β€ƒβ€ƒβˆŸπŸ“‚ Dive into Encapsulation, Polymorphism & Abstraction
β€ƒβ€ƒβ€ƒβˆŸπŸ“‚ Explore Templates & the Standard Template Library (STL)

πŸ“‚ Memory Management & Pointers
β€ƒβˆŸπŸ“‚ Grasp Pointers, References & Dynamic Memory Allocation
β€ƒβ€ƒβˆŸπŸ“‚ Master Manual Memory Management
β€ƒβ€ƒβ€ƒβˆŸπŸ“‚ Learn Smart Pointers & RAII Principles

πŸ“‚ Data Structures & Algorithms
β€ƒβˆŸπŸ“‚ Study Arrays, Vectors, Lists, Maps & Sets
β€ƒβ€ƒβˆŸπŸ“‚ Understand Sorting, Searching & Recursion
β€ƒβ€ƒβ€ƒβˆŸπŸ“‚ Solve Coding Challenges to Reinforce Concepts

πŸ“‚ Tools & Build Systems
β€ƒβˆŸπŸ“‚ Get Comfortable with IDEs (e.g., Visual Studio, CLion)
β€ƒβ€ƒβˆŸπŸ“‚ Learn CMake & Other Build Tools
β€ƒβ€ƒβ€ƒβˆŸπŸ“‚ Master Git & Version Control Systems

πŸ“‚ Advanced C++ Concepts
β€ƒβˆŸπŸ“‚ Explore Lambda Functions & Modern C++ Features
β€ƒβ€ƒβˆŸπŸ“‚ Understand Multithreading & Concurrency
β€ƒβ€ƒβ€ƒβˆŸπŸ“‚ Dive into Performance Optimization & Best Practices

πŸ“‚ Debugging & Testing
β€ƒβˆŸπŸ“‚ Learn Debugging Techniques & Tools
β€ƒβ€ƒβˆŸπŸ“‚ Master Unit Testing with Frameworks (e.g., Google Test)
β€ƒβ€ƒβ€ƒβˆŸπŸ“‚ Analyze and Optimize Code Performance

πŸ“‚ Projects & Real-World Applications
β€ƒβˆŸπŸ“‚ Build Complex, End-to-End C++ Applications
β€ƒβ€ƒβˆŸπŸ“‚ Contribute to Open-Source Projects
β€ƒβ€ƒβ€ƒβˆŸπŸ“‚ Showcase Your Work on GitHub & Portfolio

πŸ“‚ Interview Preparation & Job Hunting
β€ƒβˆŸπŸ“‚ Solve C++ Coding Challenges
β€ƒβ€ƒβˆŸπŸ“‚ Master Data Structures, Algorithms & System Design
β€ƒβ€ƒβ€ƒβˆŸπŸ“‚ Network & Apply for C++ Roles

βœ…οΈ Get Hired

React "❀️" for More πŸ‘¨β€πŸ’»
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Web Development Interview Questions for Freshers

1. What happens when you type a URL in your browser and press Enter?
Answer:

DNS lookup happens to find the IP address

Browser sends an HTTP/HTTPS request to the server

Server processes and sends back HTML/CSS/JS

Browser renders the page using its rendering engine


2. What is the difference between GET and POST requests?
Answer:

GET: Sends data in the URL, used for fetching data

POST: Sends data in the body, used for submitting data securely


3. What is a responsive website?
Answer:
A responsive website adjusts layout and design based on screen size and device (mobile, tablet, desktop), usually using CSS media queries.

4. What is the role of Webpack in web development?
Answer:
Webpack bundles JavaScript files, CSS, and assets into optimized output for faster website loading and better performance.

5. What is the purpose of async and defer in script tags?
Answer:

async: Loads script asynchronously and executes it immediately

defer: Loads script asynchronously but executes after HTML is parsed


6. What is the difference between localStorage and sessionStorage?
Answer:

localStorage: Stores data with no expiration

sessionStorage: Stores data until the browser tab is closed


7. What is CORS?
Answer:
CORS (Cross-Origin Resource Sharing) is a browser security feature that restricts cross-domain API calls unless the server allows it.

8. What is the difference between null and undefined in JavaScript?
Answer:

undefined: A variable declared but not assigned a value

null: A variable explicitly set to have no value


9. How do you optimize website performance?
Answer:

Minify CSS/JS

Compress images

Use lazy loading

Use caching

Reduce HTTP requests

Use a CDN


10. What is the DOM?
Answer:
DOM (Document Object Model) represents the structure of an HTML document as objects, which JavaScript can interact with to change content dynamically.

Credits: https://whatsapp.com/channel/0029VaiSdWu4NVis9yNEE72z/847
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Web Development Interview Questions Part-2

11. What are semantic HTML elements?
Answer:
Semantic elements clearly describe their meaning in a human- and machine-readable way. Examples: <header>, <footer>, <article>, <nav>.

12. What are HTTP status codes?
Answer:
They indicate the result of an HTTP request.
Common ones:

200 OK (Success)

404 Not Found

500 Internal Server Error

401 Unauthorized

403 Forbidden


13. What is the box model in CSS?
Answer:
The box model includes:

Content

Padding

Border

Margin
It defines how space is taken up around HTML elements.


14. What are pseudo-classes in CSS?
Answer:
Pseudo-classes style elements based on their state.
Examples:

:hover (when mouse is over)

:first-child

:nth-child()


15. How do you make a website SEO-friendly?
Answer:

Use semantic HTML

Add meta tags and alt text

Mobile responsiveness

Fast loading speed

Proper URL structure


16. What is the difference between synchronous and asynchronous in JavaScript?
Answer:

Synchronous: Code runs line by line

Asynchronous: Tasks like API calls don't block other code; use callbacks, promises, or async/await


17. What is a promise in JavaScript?
Answer:
A Promise represents the result of an async operation.
It can be:

Pending

Fulfilled

Rejected


18. What is event bubbling and capturing in JavaScript?
Answer:

Bubbling: Event propagates from child to parent

Capturing: Event goes from parent to child
You can control it using event.stopPropagation()


19. What is a CDN?
Answer:
CDN (Content Delivery Network) delivers static files (images, CSS, JS) via servers closest to the user to improve website speed.

20. What tools do you use for version control?
Answer:
Most common: Git + GitHub
Git tracks changes in code, and GitHub helps you collaborate and manage versions.

Credits: https://whatsapp.com/channel/0029VaiSdWu4NVis9yNEE72z/847
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SQL can be simpleβ€”if you learn it the smart way..



If you’re aiming to become a data analyst, mastering SQL is non-negotiable.
Here’s a smart roadmap to ace it:

1. Basics First: Understand data types, simple queries (SELECT, FROM, WHERE). Master basic filtering.

2. Joins & Relationships: Dive into INNER, LEFT, RIGHT joins. Practice combining tables to extract meaningful insights.

3. Aggregations & Functions: Get comfortable with COUNT, SUM, AVG, MAX, GROUP BY, and HAVING clauses. These are essential for summarizing data.

4. Subqueries & Nested Queries: Learn how to query within queries. This is powerful for handling complex datasets.

5. Window Functions: Explore ranking, cumulative sums, and sliding windows to work with running totals and moving averages.

6. Optimization: Study indexing and query optimization for faster, more efficient queries.

7. Real-World Scenarios: Apply your SQL knowledge to solve real-world business problems.

The journey may seem tough, but each step sharpens your skills and brings you closer to data analysis excellence. Stay consistent, practice regularly, and let SQL become your superpower! πŸ’ͺ

Here you can find essential SQL Interview ResourcesπŸ‘‡
https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v

Like this post if you need more πŸ‘β€οΈ

Hope it helps :)
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πŸ’‘ Tips to Crack Top Tech Companies using LeetCode πŸ’»

Are you aiming to crack top tech companies? Here are some tips on how to effectively use the LeetCode platform to enhance your problem-solving skills and increase your chances of success:

1️⃣ Quality > Quantity βœ…

Rather than focusing on solving a large number of problems, prioritize the quality of your solutions. It's better to solve a particular Data Structures and Algorithms (DSA) sheet thoroughly and revise it until you can build up the logic on your own. Consider using resources like the Striver Sheet or Grind 75 to guide your practice.

2️⃣ Maintain an Error Sheet βœ…

Create an error sheet to keep track of the questions you've solved and the mistakes you've made while solving them. By reviewing this sheet regularly, you can identify common errors and strive to avoid repeating them. This practice will significantly improve your problem-solving skills over time.

3️⃣ Solve Top Interview Questions βœ…

When preparing for a specific company's interview, focus on solving recent LeetCode questions that are tagged with that company's name. This way, you'll be familiar with the types of problems the company typically asks and be better prepared for the interview.

4️⃣ For Beginners βœ…

If you're new to problem-solving, it's advisable to start with Easy-level problems before moving on to Medium or Hard ones. Aim to solve at least 25 problems in the Easy category before challenging yourself with more complex ones. This approach helps build a strong foundation and boosts your confidence.

5️⃣ Practice Weak Topics Regularly βœ…

Identify the topics or problem types that you find challenging or fear the most. For example, if you struggle with graph problems, make it a habit to solve at least one graph problem every day. Regular practice in your weaker areas will help you improve your skills and boost your overall performance.

6️⃣ Don't Ignore Acceptance Level βœ…

When browsing problems on LeetCode, consider sorting them by acceptance level. Prioritizing problems with a higher acceptance rate increases the likelihood of successfully solving them. This strategy allows you to build confidence by tackling problems that have been well-received by other users.

7️⃣ Don't Ignore Other Solutions βœ…

Even if your solution is correct and accepted, don't overlook the opportunity to learn from others. Explore alternative solutions to the same problem. This practice exposes you to different approaches, algorithms, and optimizations, enabling you to discover new and efficient ways of solving problems.

8️⃣ Consistency is the Key βœ…

Maintain a consistent practice schedule to make steady progress. Dedicate a block of time, such as 2-3 hours each day, to solve LeetCode problems. Additionally, set aside a specific day, like Saturdays, for weekly revisions. Consistency and regular practice will sharpen your problem-solving skills and increase your chances of cracking top tech company interviews.

Good luck with your LeetCode journey! πŸš€
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