AtCoder Python Dev Container

Important

日本語版はこちら

This repository provides a ready-to-use VS Code Dev Container for competitive programming on AtCoder.

Environment

• Python 3.13 (slim)
• online-judge-tools (oj) with tab completion
• Jupyter
• Selenium (for silencing warnings on oj use)

🚀 Setup Instructions

Follow these steps to get the same development environment on Windows, macOS, or Linux.

1. Install prerequisites

   • Git
   • Docker
     • Windows/macOS → install Docker Desktop
     • Linux → install Docker engine via your package manager.
   • Visual Studio Code (VS Code)
   • Dev Containers extension for VS Code (See tutorial)

2. Fork this repository

3. Clone repo to local Open a terminal and run:

git clone https://github.com/<your-github-username>/Atcoder_Python.git
cd Atcoder_Python

4. Open in VS Code

   1. Launch VS Code.
   2. Open the cloned folder (File → Open Folder).
   3. If the Dev Containers extension is installed, you’ll see a prompt: “Reopen in Container”. Click it.
   • Or, open the Command Palette (Ctrl+Shift+P or Cmd+Shift+P on macOS) and run: “Dev Containers: Reopen in Container”

   VS Code will then:

   • Build the Docker image from .devcontainer/Dockerfile.
   • Mount your project into the container at /workspaces/Atcoder_python.
   • Install Python, oj, Jupyter, and Selenium automatically.

Warning

Important: work/ folder

• This repository contains a folder called work/.
• It is where you should put all your own contest code and notebooks.
• Before starting to use the container, please delete the existing contents of work/ — those are my solutions, kept here only as an example.
• Once emptied, the work/ folder will serve as your personal workspace.

✅ Usage

Run Python scripts: python main.py

Please refer https://github.com/online-judge-tools/oj

Download a problem with oj:

oj download https://atcoder.jp/contests/abc999/tasks/abc999_a

Test locally: oj test

Start JupyterLab (port 8888 will be forwarded automatically):

jupyter lab --ip=0.0.0.0 --no-browser --NotebookApp.token=''

🐳 Notes

• Always fork → clone your fork so you can push your own solutions to GitHub.
• All code runs inside the container, so your local system stays clean.
• Your workspace is bind-mounted → changes are saved directly in your local files.
• Works on Windows (via WSL2), macOS (Intel/Apple Silicon), and Linux.

🙌 Contributing

Feel free to open issues or PRs to improve the environment (e.g., add useful extensions, packages, or helper scripts).