🚀 AI-Powered LeetCode Problem Solver & Learning Companion

Master Data Structures & Algorithms with AI-Driven Insights

Features • Getting Started • API Documentation • Contributing

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📖 About The Project

CodeMentor AI is an intelligent coding assistant that revolutionizes how you learn and solve LeetCode problems. Powered by Google's Gemini AI, it provides:

• 🎯 Comprehensive Problem Analysis - Deep dive into problem statements with AI-powered insights
• 🧠 Intelligent Learning Path - Step-by-step guidance tailored to your learning style
• ⚡ Optimized Solutions - Industry-standard code with best practices
• 📊 Performance Metrics - Detailed time and space complexity analysis
• 🎓 Interview Preparation - Real-world problem-solving techniques

Whether you're preparing for FAANG interviews, strengthening your DSA fundamentals, or exploring algorithmic thinking, CodeMentor AI is your ultimate learning companion!

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✨ Features

🤖 AI-Powered Intelligence

• Smart Problem Breakdown - Gemini AI analyzes and explains problems in simple terms
• Multiple Approaches - Learn different solutions from brute force to optimal
• Code Explanation - Line-by-line breakdown of the solution

📚 Comprehensive Learning

• Step-by-Step Guidance - Clear progression from problem understanding to implementation
• Pattern Recognition - Identify common problem-solving patterns
• Complexity Analysis - Detailed Big-O notation for time and space

🔐 User Management

• Secure Authentication - JWT-based login system
• Problem History - Access previously solved problems

💾 Robust Backend

• MongoDB Integration - Scalable data persistence
• RESTful API - Clean and documented endpoints
• Error Handling - Comprehensive error management

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🏗️ System Architecture

┌──────────────────────────────────────────────────────────────┐
│                    Frontend (Coming Soon)                    │
│           React.js + Tailwind CSS + TypeScript               │
└────────────────────────┬─────────────────────────────────────┘
                         │ REST API
                         ▼
┌──────────────────────────────────────────────────────────────┐
│                    Express.js Backend                        │
│                                                              │
│  ┌────────────┐   ┌──────────────┐   ┌─────────────────┐   │
│  │  Routes    │──▶│ Controllers  │──▶│  Middleware     │   │
│  │  Layer     │   │  (Business   │   │  (Auth/Logging) │   │
│  └────────────┘   │   Logic)     │   └─────────────────┘   │
│                   └──────┬───────┘                          │
│                          │                                  │
│                   ┌──────▼───────┐                          │
│                   │    Models    │                          │
│                   │   (Schemas)  │                          │
│                   └──────────────┘                          │
└──────────┬────────────────────────────┬─────────────────────┘
           │                            │
           ▼                            ▼
┌──────────────────────┐    ┌──────────────────────────┐
│   Gemini AI API      │    │   MongoDB Atlas/Local    │
│                      │    │                          │
│ • Problem Analysis   │    │ • User Authentication    │
│ • Solution Generation│    │ • Problem Storage        │
│ • Code Explanation   │    │ • Progress Tracking      │
└──────────────────────┘    └──────────────────────────┘

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🚀 Getting Started

Prerequisites

Ensure you have the following installed on your system:

• Node.js (v14.x or higher) - Download
• npm (v6.x or higher) or yarn (v1.22.x or higher)
• MongoDB - Local Installation or MongoDB Atlas
• Google Gemini API Key - Get your free API key
• Git - Download

Quick Start Guide

1️⃣ Clone the Repository

git clone https://github.com/nikhilxagr/Code-Mentor-AI.git
cd Code-Mentor-AI

2️⃣ Install Dependencies

cd backend
npm install

3️⃣ Environment Configuration

Create a .env file in the backend directory:

# Server Configuration
PORT=5000
NODE_ENV=development

# Database Configuration
MONGO_URI=mongodb://localhost:27017/codementor
# For MongoDB Atlas: mongodb+srv://<username>:<password>@cluster.mongodb.net/codementor

# Google Gemini AI
GEMINI_API_KEY=your_gemini_api_key_here

# JWT Authentication
JWT_SECRET=your_super_secret_jwt_key_here
JWT_EXPIRE=7d

# CORS Settings
CORS_ORIGIN=http://localhost:3000

4️⃣ Start MongoDB

Local MongoDB:

mongod

MongoDB Atlas:

• Copy your connection string from Atlas dashboard
• Update MONGO_URI in .env

5️⃣ Run the Development Server

npm start

For development with auto-reload:

npm run dev

Your server should now be running on http://localhost:5000 🚀

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🛠️ Tech Stack

Backend Technologies

Technology	Version	Purpose
Node.js	v14+	JavaScript runtime environment
Express.js	v4.18+	Fast, unopinionated web framework
MongoDB	v5.0+	NoSQL database for data persistence
Mongoose	v7.0+	Elegant MongoDB object modeling
Google Gemini AI	Latest	Advanced AI for problem solving
bcryptjs	v2.4+	Secure password hashing
jsonwebtoken	v9.0+	JWT-based authentication
dotenv	v16.0+	Environment variable management
cors	v2.8+	Enable cross-origin requests

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📡 API Endpoints

🧠 Problem Solving Endpoints

Get AI Solution

POST /api/solve
Content-Type: application/json

{
  "problemNumber": 1
}

Response:

{
  "success": true,
  "problem": {
    "number": 1,
    "title": "Two Sum",
    "difficulty": "Easy"
  },
  "answer": {
    "explanation": "Detailed problem breakdown...",
    "approach": "Step-by-step solution approach...",
    "solution": "Code implementation with explanation...",
    "complexity": {
      "time": "O(n)",
      "space": "O(n)"
    }
  }
}

📊 Utility Endpoints

Health Check

GET /api/health

Response:

{
  "status": "success",
  "message": "CodeMentor AI is running!",
  "timestamp": "2024-01-15T10:30:00Z"
}

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🗂️ Project Structure

Code-Mentor-AI/
│
├── backend/
│   ├── config/
│   │   ├── db.js                      # MongoDB connection configuration
│   │   └── gemini.js                  # Gemini AI initialization
│   │
│   ├── controllers/
│   │   ├── auth.controller.js         # Authentication logic
│   │   └── solve.controller.js        # Problem solving logic
│   │
│   ├── middleware/
│   │   ├── auth.middleware.js         # JWT verification
│   │   └── error.middleware.js        # Error handling
│   │
│   ├── models/
│   │   ├── User.model.js              # User schema
│   │   └── Problem.model.js           # Problem schema
│   │
│   ├── routes/
│   │   ├── auth.routes.js             # Authentication routes
│   │   └── solve.routes.js            # Problem solving routes
│   │
│   ├── .env                           # Environment variables (gitignored)
│   ├── .env.example                   # Example environment file
│   ├── .gitignore                     # Git ignore rules
│   ├── server.js                      # Entry point
│   ├── package.json                   # Dependencies
│   └── package-lock.json              # Dependency lock file
│
├── frontend/                          # (Coming Soon)
│   └── README.md
│
├── .gitignore                         # Root git ignore
├── LICENSE                            # MIT License
└── README.md                          # This file

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🎯 How It Works

Problem Solving Flow

1. User Submits Problem Number
   ↓
2. Problem Validation
   ↓
3. Gemini AI Processing
   ├── Problem Analysis
   ├── Solution Generation
   ├── Code Optimization
   └── Complexity Calculation
   ↓
4. Response Formatting
   ↓
5. Return to User

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🔧 Configuration

Environment Variables

Variable	Description	Default	Required
PORT	Server port	5000	No
MONGO_URI	MongoDB connection string	-	Yes
GEMINI_API_KEY	Google Gemini API key	-	Yes
JWT_SECRET	Secret for JWT signing	-	Yes
JWT_EXPIRE	JWT token expiration	7d	No
NODE_ENV	Environment mode	development	No
CORS_ORIGIN	Allowed CORS origins	*	No

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🐛 Troubleshooting

Common Issues

MongoDB Connection Error

Error: MongoNetworkError: failed to connect to server

Solution:

• Check if MongoDB is running: mongod --version
• Verify MONGO_URI in .env
• Ensure IP whitelist in MongoDB Atlas

Gemini API Error

Error: Invalid API key

Solution:

• Verify API key in .env
• Check API quota at Google AI Studio

Port Already in Use

Error: listen EADDRINUSE: address already in use :::5000

Solution:

# Find and kill the process
lsof -ti:5000 | xargs kill -9

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🤝 Contributing

Contributions make the open-source community thrive! We welcome contributions of all kinds.

How to Contribute

1. Fork the Project

   git clone https://github.com/nikhilxagr/Code-Mentor-AI.git

2. Create Feature Branch

   git checkout -b feature/AmazingFeature

3. Make Changes

   • Write clean, documented code
   • Follow existing code style

4. Commit Changes

   git commit -m 'Add: Amazing new feature'

5. Push to Branch

   git push origin feature/AmazingFeature

6. Open Pull Request

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📋 Roadmap

• Backend API with Express.js
• MongoDB Integration
• Gemini AI Integration
• User Authentication System
• Frontend Development (React.js)
• User Dashboard
• Progress Tracking
• Problem Recommendation System

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📜 License

Distributed under the MIT License. See LICENSE for more information.

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👨‍💻 Authors & Contributors

Project Collaborators

Nikhil Agrawal Full Stack Developer

Gaurav Kumar Yadav Full Stack Developer

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🙏 Acknowledgments

Special thanks to:

• Google Gemini AI - For powerful AI capabilities
• LeetCode - For the amazing problem database
• MongoDB - For robust database solutions
• Express.js - For the excellent web framework
• Open Source Community - For continuous inspiration

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📞 Support

Need help? We're here for you!

• 🐛 Bug Reports: GitHub Issues
• 💬 Discussions: GitHub Discussions

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🌟 Show Your Support

If CodeMentor AI helped you ace your interviews or improve your coding skills, give it a ⭐️!

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📊 Project Stats

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Made with 💜 by Nikhil Agrawal & Gaurav Kumar Yadav

Happy Coding! 🚀

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"The only way to learn a new programming language is by writing programs in it." - Dennis Ritchie