A comprehensive collection for FAANG-style technical interviews
DSA | JavaScript Core | React LLD | System Design

• Overview
• Quick Start
• DSA Problems
• JavaScript Concepts
• React LLD Components
• React Hooks
• System Design
• Project Structure
• Contributing

This repository is a one-stop interview preparation hub covering all aspects of technical interviews:

• Zero Dependencies - Pure implementations, no external libraries
• Self-Documenting - Each file includes problem statement, intuition & complexity analysis
• Runnable Tests - Execute DSA files directly with Node.js
• Interactive Demo - React app to visualize LLD components
• Interview Ready - Common follow-up questions included
• DSA Tracker - CSV with 125 problems, categories, priorities & intuitions

# Run any DSA problem directly
node DSA/Graph/numberOfIslands.js
node DSA/Two-Pointer/trappingRainWater.js

cd practice
npm install
npm run dev
# Open http://localhost:5173

125 curated problems organized by pattern/technique. Full tracking available in DSA/dsa-preparation-list.csv with:

• Problem name & LeetCode number
• Difficulty & Category
• Priority (Must Do / Core / Depth)
• Completion status
• Algorithm intuition for each problem

Arrays/Strings  ████████████████░░░░  28 problems
Graph/Matrix    ████████████████████  26 problems
Trees           ███████████░░░░░░░░░  11 problems
DP              █████████░░░░░░░░░░░   9 problems
Binary Search   ██████░░░░░░░░░░░░░░   6 problems
Sliding Window  ██████░░░░░░░░░░░░░░   6 problems
Stack           ██████░░░░░░░░░░░░░░   6 problems
Linked List     ██████░░░░░░░░░░░░░░   6 problems
Others          █████████████████░░░  27 problems

Each DSA file follows this structure:

/**
 * ============================================================================
 * PROBLEM: [Name] (LeetCode #XXX)
 * ============================================================================
 * [Problem description with examples]
 *
 * ============================================================================
 * INTUITION: [Algorithm Name]
 * ============================================================================
 * [Why this approach works, key insights]
 *
 * Time Complexity: O(...)
 * Space Complexity: O(...)
 */

// Implementation with detailed comments
// Multiple approaches (DFS, BFS, Union-Find, etc.)
// Comprehensive test cases at the bottom

Core JavaScript implementations for interview questions:

Interactive low-level design problems with working solutions:

• problem.md - Requirements & visual representation
• Solution.jsx - Working implementation
• Key concepts & interview tips
• Common follow-up questions
• Edge cases to consider

Reusable custom hooks for common UI patterns:

15 comprehensive frontend system design documents for interviews:

1. Requirements (Functional & Non-Functional)
2. Component Architecture
3. State Management Strategy
4. API Design & Data Flow
5. Performance Optimizations
6. Accessibility Considerations
7. Error Handling & Edge Cases
8. Testing Strategy
9. Security Considerations
10. Deployment & Monitoring

.
├── DSA/                          # Data Structures & Algorithms (125 problems)
│   ├── dsa-preparation-list.csv  # Master tracking with intuitions
│   ├── Arrays&Hashset/
│   ├── BinarySearch/
│   ├── Graph/                    # 10 fully documented graph problems
│   ├── Two-Pointer/
│   ├── intervals/
│   ├── matrix/
│   ├── recursion & backtracking/
│   ├── sliding-window/
│   └── tree/
│
├── JavaScriptProblems/           # Pure JavaScript (34+ implementations)
│   ├── Array/                    # Array method polyfills
│   ├── Design Patterns/          # Common patterns
│   ├── call,apply,bind/          # Function context
│   ├── memoization/              # Caching strategies
│   ├── promise-async-problems/   # Async utilities
│   ├── promise-polyfills/        # Promise implementations
│   └── utility/                  # Helper functions
│
├── practice/                     # React LLD App
│   ├── src/
│   │   ├── components/           # App shell components
│   │   └── lld/                  # 7 LLD problem solutions
│   └── package.json
│
├── reactHooks/                   # 6 Custom React hooks
│
├── system-design/                # 15 Frontend architecture templates
│   ├── instagram-photo-feed.md
│   ├── news-feed-facebook-twitter.md
│   ├── video-streaming-youtube.md
│   ├── ecommerce-marketplace-amazon.md
│   └── ... (11 more)
│
└── Theory/                       # Supporting educational content

Contributions are welcome! Please follow these guidelines:

1. DSA Problems: Include problem link, intuition, brute force & optimal solutions, complexity analysis
2. JavaScript: Provide polyfill with edge case handling
3. React LLD: Include problem.md with requirements and visual representation
4. System Design: Follow the existing template format with all 10 sections

• LeetCode - DSA practice
• GreatFrontEnd - Frontend interview prep
• React Documentation - Official React docs
• NeetCode - DSA roadmap

Happy Coding!
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