OJ Data Analyzer

Online Judge data analysis and problem recommendation tool for competitive programmers. Currently supports Codeforces, with AtCoder integration planned.

Core Features

• Rating Analysis — rating trends, peaks, volatility, and recent performance over time
• Tag Analysis — tag frequency, solve rate, and average difficulty per algorithmic topic
• Strengths & Weaknesses — proficiency scoring per tag, identifying mastered vs. underdeveloped areas
• Visualization — interactive charts (rating history line chart, tag distribution bar chart, strength/weakness radar chart)
• Problem Recommendations — tag-based recommendation engine with rating-range matching and diversity optimization
• AI Coach (planned) — AI-powered personalized analysis and training advice

Tech Stack

Layer	Technology
Frontend	React 18, TypeScript, Vite, Recharts
Backend	FastAPI (Python), httpx
Data Analysis	Pandas
Data Source	Codeforces API (public)

Getting Started

Prerequisites

• Python 3.10+
• Node.js 18+

Backend

cd backend
pip install -r requirements.txt
python -m uvicorn main:app --reload --port 8000

The API server starts at http://localhost:8000. Interactive docs available at http://localhost:8000/docs.

Frontend

cd frontend
npm install
npm run dev

The dev server starts at http://localhost:5173 with API requests proxied to the backend.

API Endpoints

Method	Path	Description
GET	/	Health check
GET	/api/user/{handle}	User info + rating history
GET	/api/user/{handle}/submissions	Submission history (paginated)
GET	/api/user/{handle}/analysis	Combined analysis (rating + tags + strengths)
GET	/api/user/{handle}/recommend	Problem recommendations
GET	/api/contests	Contest list
GET	/api/problemset	Problemset search

Development Status

Phase	Feature	Status
Phase 1	Codeforces API integration	Done
Phase 2	Data analysis engine	Done
Phase 3	Visualization (React + Recharts)	Done
Phase 4	Problem recommendation system	Done
Phase 5	AtCoder API integration	Blocked — upstream API (Kenkoooo) returns 403; exploring Playwright-based alternative
Phase 6	AtCoder analysis & recommendations	Pending Phase 5
Phase 7	AI Coach	Planned
Phase 8	Production deployment	Planned

AtCoder's official site has no public API. The Kenkoooo API (a widely-used community data source) has blocked external access. We are evaluating Playwright-based scraping of the AtCoder official site or AtCoder Problems frontend as a fallback.

Project Structure

backend/
├── main.py                   # FastAPI entry point
├── api/                      # Route handlers
├── analysis/                 # Data analysis modules (rating, tags, strengths)
├── recommender/              # Recommendation engine
├── services/                 # External API clients
└── models/                   # Data models (placeholder)

frontend/
├── src/
│   ├── components/           # Reusable UI components
│   ├── charts/               # Recharts-based chart components
│   ├── pages/                # Page-level components
│   ├── App.tsx               # Root component
│   └── types.ts              # TypeScript type definitions
└── vite.config.ts            # Vite build config + API proxy

Contributing

1. File an issue to discuss proposed changes before starting work
2. Follow the existing module structure — API handlers in backend/api/, analysis logic in backend/analysis/
3. Do not modify existing API signatures without prior discussion
4. Use TypeScript strict mode for frontend changes
5. Match the existing dark theme and responsive layout conventions for UI work

License

MIT