What Is CP Editor?

Updated

CP Editor is a desktop IDE built specifically for competitive programmers. It automates the repetitive parts of contest work — compiling, running, and testing your code against expected outputs — and pulls sample test cases from platforms like Codeforces and AtCoder with a single click. It's aimed at anyone who writes contest solutions in C/C++, Java, or Python and wants to spend their time on algorithms rather than on manually pasting inputs and diffing outputs.

What it actually does

The editor's stated goal is to "automate everything that's reasonably possible" so you can focus purely on your code. In practice that means four things:

  • Fetch test cases — Pull sample test cases from Codeforces, AtCoder, and other competitive programming platforms with one click, instead of copying them by hand.
  • Compile & run — Compile and run your solution against multiple test cases instantly, then compare your output against the expected results and get a verdict.
  • Submit solutions — Submit directly to Codeforces through CF Tool, and view submission verdicts without leaving the editor.
  • Run without saving — Test something quickly with one click without saving the file; a hot-exit feature restores your code from the last session.

Who it's for

CP Editor targets competitive programmers — people solving timed problems on judges like Codeforces and AtCoder. It officially supports C/C++, Java, and Python, so if your contest language is one of those three, it fits your workflow directly.

If you only write code occasionally, or you work in a language outside that set, the automation it offers matters less. The value scales with how many problems you test per session.

How it differs from manual testing

The manual loop for a contest problem usually looks like this: write code, save, switch to a terminal, compile, paste the sample input, run, eyeball the output against the expected output, repeat for each sample, then copy your file into a submit form. Every step is a context switch.

CP Editor collapses that loop into the editor itself. Test cases arrive automatically, compilation and execution happen on command, and output comparison is done for you. Submission to Codeforces happens in place. The site frames the whole product as saying "no to manual efforts of running and testing your code against expected outputs."

Editor features worth knowing

Beyond the automation, the current version (7.0) adds:

Feature What it gives you
KSyntaxHighlighting Hundreds of color themes, the same framework used by the Kate editor — Light, Dracula, Monokai, Solarized, and more
Code folding & split views A clean, adaptive interface for navigating larger solutions
Real-time diagnostics Language Server Protocol (LSP) checks your code as you type, underlining errors and warnings with squiggly lines and hover tooltips
Customizable colors You can adjust diagnostic colors to taste

The LSP-based linting is the feature most likely to save contest time, since it surfaces errors before you ever hit compile.

Getting it

CP Editor is distributed through its GitHub repository and a download link on the project site. The source page does not state pricing, so check the repository for licensing and current release details before installing. If you compete regularly on Codeforces or AtCoder in C/C++, Java, or Python, it's worth trying on your next practice round to see whether the fetch-and-test automation matches how you work.