Codeforces Auto Problem Code

A Chrome extension that automatically fills in the problem code on Codeforces submit pages, so you never have to type 1850A by hand again.

What it does

Remembers the last problem you opened (contest, problemset, gym, or group).
When you click Codeforces's own "Submit" link and land on any submit page, it auto-fills the problem code:
- problemset/submit → fills the text box.
- contest/{id}/submit, gym, group → selects the right problem in the dropdown.
No extra buttons are added — it works with Codeforces's built-in submit flow.
Only ever touches the problem code — it never changes your language or your source code.
Toggle it on/off from the popup.

Chrome doesn't allow one-click installs from outside its Web Store, so this is a quick manual install (takes under a minute):

On this repo's page, click the green Code button → Download ZIP (or grab the latest .zip from the Releases section).
Unzip it somewhere permanent — e.g. Documents\codeforces-auto-problem-code. (If you delete this folder later, the extension stops working.)
Open Chrome and go to chrome://extensions.
Turn on Developer mode (top-right toggle).
Click Load unpacked and select the unzipped folder (the one containing manifest.json).
The "CF" icon appears in your toolbar. Pin it if you like. Done.

Open any Codeforces problem (e.g. codeforces.com/contest/1850/problem/A).
Click Codeforces's own Submit link as usual.
On the submit page the problem code is already filled in — pick your language, paste your code, and submit.

After editing any file, go to chrome://extensions and click the reload (↻) icon on this extension's card.

Works on codeforces.com and its mirrors (m1/m2/m3.codeforces.com).
Privacy: stores only the last-viewed problem code locally on your device and sends no data anywhere.
If Codeforces ever changes its form field names, the selectors in content.js (submittedProblemCode, submittedProblemIndex) may need updating.