A focused code editor for competitive programming on Codeforces — fetch problems, write solutions, and test locally, all in one window.
Important
CP Ally IDE is currently in beta. Expect occasional bugs and rough edges.
- Why CP Ally IDE?
- Demo
- Features
- Installation
- Building from Source
- Deep Link Protocol
- Keyboard Shortcuts
- Contributing
- License
- Contributors
Most IDE setups for competitive programming require switching between a browser for the problem statement, a text editor for code, and a terminal for testing. CP Ally IDE puts all three in a single window so you can stay focused on the problem.
It is built specifically for Codeforces workflows: type a problem code, read the statement, write a solution, and run it against the sample tests — without touching a browser or a separate terminal.
Click the image above to watch the demo video (v0.1.3 beta).
- Fetch any Codeforces problem by its contest code and index (e.g.
2208A). - Renders the full problem statement with HTML, inline icons, and LaTeX math.
- Shows a statement-only view alongside a full view that includes sample test cases.
- Detects and discards bot-check pages — re-fetches automatically when the cached page is invalid.
- One-click Refresh Problem to re-fetch without clearing your editor.
- Open problems from anywhere with
cpally://problem/2208Alinks. - If the app is already running, the link is forwarded to it instantly — no second window opens.
- If the app is closed, it starts and loads the problem automatically.
- Registered by the Windows installer; removed cleanly on uninstall.
- When a problem is loaded, the app automatically checks the CP Ally practice sheet index.
- If the problem belongs to any sheets, they are listed at the bottom of the problem statement as clickable links.
- Syntax-highlighted editor powered by RSyntaxTextArea.
- Supports C++, Java, Python 3, and other common languages via a language dropdown.
- Bracket auto-pairing with selection-wrapping support.
- Independent zoom control for the editor and the problem pane.
- Autosave with configurable interval.
- Extracts sample test cases from the problem statement automatically.
- Add custom test cases with your own input and expected output (
Ctrl+Shift+T). YES/NOoutputs are judged case-insensitively.- Displays execution time, memory usage, and detailed comparison results.
- Problem statements are cached locally — previously opened problems load instantly.
- Source code is cached per problem code and language — your work is restored when you return.
- Separate menu actions to clear the problem cache or the code cache.
- Multiple themes: Dark, Ultra Dark, and Light, switchable from Preferences.
- Persistent window state: size, divider positions, last-used language, and zoom levels.
- Splash screen on startup.
- Diagnostic log written to
%APPDATA%\CompetitiveProgrammingAlly\diagnostics.log.
- Go to the Releases page.
- Download
mysetup.exefrom the latest release. - Run the installer and follow the prompts.
- The app is added to the Start Menu and optionally to the Desktop.
- The
cpally://URL protocol is registered automatically.
Minimum requirement: Windows 10 or later. A Java runtime is bundled — you do not need to install Java separately.
If you have Java 17 or later installed:
java -jar cp-ally-ide-0.2.2.jarDownload the JAR from the Releases page. The cpally:// protocol handler is not set up automatically when running the JAR directly.
Prerequisites
| Tool | Version |
|---|---|
| Java JDK | 17 or later |
| Maven | 3.8 or later |
Steps
# Clone the repository
git clone https://github.com/0xPolybit/cp-ally-ide.git
cd cp-ally-ide
# Build the fat JAR (includes all dependencies)
mvn package
# Run directly
java -jar target/cp-ally-ide-0.2.2.jarThe build produces a single self-contained JAR at target/cp-ally-ide-0.2.2.jar.
Packaging for Windows
To produce a distributable Windows installer:
- Wrap the JAR with Launch4j to create an EXE.
- Build the installer with Inno Setup using the
.issscript in the project.
The Inno Setup script handles bundling the JRE, registering the cpally:// URL protocol, and creating Start Menu/Desktop shortcuts.
CP Ally IDE registers the cpally:// URL scheme on installation. Use it to open problems directly from any browser, markdown file, or launcher.
URL format
cpally://problem/<code>
Examples
cpally://problem/1A
cpally://problem/2208A
cpally://problem/1900F
How it works
| Scenario | Behaviour |
|---|---|
| App is closed | Launches the app, shows splash, then loads the problem |
| App is running | Forwards the URL to the running instance; no second window opens |
| App is minimized | Restores and brings the window to front, then loads the problem |
You can also trigger a link from the command line:
start cpally://problem/2208A| Action | Shortcut |
|---|---|
| Choose Problem | Ctrl+N |
| Open Empty Editor | Ctrl+E |
| Run Code | Ctrl+R |
| Preferences | Ctrl+P |
| Add Test Case | Ctrl+Shift+T |
| Zoom In | Ctrl+= |
| Zoom Out | Ctrl+- |
| Reset Zoom | Ctrl+0 |
Contributions are welcome. Keep changes focused on the competitive programming workflow — fast problem fetching, local execution, and a minimal interface.
Guidelines
- Keep the UI practical and contest-friendly.
- Do not introduce breaking changes to the cache file format without handling migration.
- Prefer targeted, small changes over broad refactors.
- If the change affects UI layout or rendering, test it in the running app.
- Update this README if the change affects setup or user-facing behavior.
Workflow
- Fork the repository and create a feature branch from
main. - Make your change and build locally with
mvn package. - Verify the app starts and the affected feature works.
- Open a pull request with a clear description of what changed and why.
Reporting bugs
Open an issue at github.com/0xPolybit/cp-ally-ide/issues. Include the problem code you were using (if relevant), the contents of %APPDATA%\CompetitiveProgrammingAlly\diagnostics.log, and a description of what you expected vs. what happened.
Licensed under the Apache License 2.0.
You may use, modify, and redistribute this software under the terms of that license. Distributed copies must retain the license notice and attribution.
| Name | Role | |
|---|---|---|
 |
Swastik Biswas | Owner & maintainer |
 |
Himanshi Saxena | Contributor |
If your contribution is merged, add your name to this table in the same pull request.