**TL;DR:** I couldn't register on usaco.org (Gmail verification bug), so I built [OJCloud](https://app.ojcloud.net) — all **484 USACO problems** (2011–2024, Bronze → Platinum) on a modern judge with partial scoring, 16 languages, real-time per-test-case verdicts, progress tracking, and both ICPC/IOI contest modes. Everything uses standard I/O. Register with just a handle + password — no email, no OAuth, no waiting.↵
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[cut]↵
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Hello, Codeforces!↵
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I've been using USACO problems to train for years, but practicing them on usaco.org always felt unnecessarily painful — so I built a judge that just works.↵
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The friction is real: Gmail users [often don't receive verification emails](https://usaco.guide/general/usaco-faq) and the only fix is emailing the contest director personally. Pre-2020 problems silently require file I/O — your code compiles, runs, produces correct output locally, but gets WA on the judge with zero explanation (this is the [#1 cause of "it works on my machine"](https://usaco.guide/general/input-output) reports). There's no dashboard to track what you've solved, and the submit button is buried at the bottom of a static archive page.↵
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I put all **484 USACO problems** (2011–2024, Bronze through Platinum) on [OJCloud](https://app.ojcloud.net) with a proper judge. Everything uses standard I/O — no file I/O surprises.↵
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### What you get↵
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- **Partial scoring** — no more guessing whether you failed 1 test case or all 20. You see exactly how many tests pass out of the total.↵
- **16 languages** — C++20/17/14/11, Python 3, PyPy 3, Java 21/8, Kotlin, Go, Rust, and more↵
- **Real-time judging** — live verdict per test case as the judge runs, not a spinner followed by a wall of results↵
- **Progress tracking** — solved count, acceptance rate, activity heatmap, submission history. You know where you stand.↵
- **Polygon-compatible checkers** — 10 built-in testlib.h checkers (wcmp, lcmp, fcmp, ncmp, rcmp, hcmp, yesno, ...) + custom checker support↵
- **Contest system** — both ICPC and IOI scoring formats, live standings↵
- **Bilingual** — full English + Vietnamese interface, auto-detected from your location↵
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### Try it↵
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484 problems and 5,000+ test cases are live. Register with just a handle and password at [app.ojcloud.net](https://app.ojcloud.net) — no email required. Pick a [USACO problem](https://app.ojcloud.net/problems), submit, and see the judge in action.↵
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Feedback welcome — comment below or [join us on Discord](https://discord.gg/RrP3YwrHyG) where we discuss USACO solutions daily.↵
↵
Thanks to [user:MikeMirzayanov,2026-03-15] for Codeforces and testlib.h — many of our design decisions were inspired by Polygon.
↵
[cut]↵
↵
Hello, Codeforces!↵
↵
I've been using USACO problems to train for years, but practicing them on usaco.org always felt unnecessarily painful — so I built a judge that just works.↵
↵
The friction is real: Gmail users [often don't receive verification emails](https://usaco.guide/general/usaco-faq) and the only fix is emailing the contest director personally. Pre-2020 problems silently require file I/O — your code compiles, runs, produces correct output locally, but gets WA on the judge with zero explanation (this is the [#1 cause of "it works on my machine"](https://usaco.guide/general/input-output) reports). There's no dashboard to track what you've solved, and the submit button is buried at the bottom of a static archive page.↵
↵
I put all **484 USACO problems** (2011–2024, Bronze through Platinum) on [OJCloud](https://app.ojcloud.net) with a proper judge. Everything uses standard I/O — no file I/O surprises.↵
↵
### What you get↵
↵
- **Partial scoring** — no more guessing whether you failed 1 test case or all 20. You see exactly how many tests pass out of the total.↵
- **16 languages** — C++20/17/14/11, Python 3, PyPy 3, Java 21/8, Kotlin, Go, Rust, and more↵
- **Real-time judging** — live verdict per test case as the judge runs, not a spinner followed by a wall of results↵
- **Progress tracking** — solved count, acceptance rate, activity heatmap, submission history. You know where you stand.↵
- **Polygon-compatible checkers** — 10 built-in testlib.h checkers (wcmp, lcmp, fcmp, ncmp, rcmp, hcmp, yesno, ...) + custom checker support↵
- **Contest system** — both ICPC and IOI scoring formats, live standings↵
- **Bilingual** — full English + Vietnamese interface, auto-detected from your location↵
↵
### Try it↵
↵
484 problems and 5,000+ test cases are live. Register with just a handle and password at [app.ojcloud.net](https://app.ojcloud.net) — no email required. Pick a [USACO problem](https://app.ojcloud.net/problems), submit, and see the judge in action.↵
↵
Feedback welcome — comment below or [join us on Discord](https://discord.gg/RrP3YwrHyG) where we discuss USACO solutions daily.↵
↵
Thanks to [user:MikeMirzayanov,2026-03-15] for Codeforces and testlib.h — many of our design decisions were inspired by Polygon.
