I think we are checking the wrong thing against LLM cheating ### 1. What exactly is the problem During rounds, a specific pattern has appeared: a participant gets ready-made code from an LLM and simply submits it, almost without understanding it. This is not always caught by plagiarism: a person can rename variables, swap some parts of the code. ### 2. The idea #### Xeppelin — an open-source tool, originally made for ICPC, which: - is launched locally before the contest - logs file changes in the working directory - stores a development timeline (when and how the code changed) - does not record the screen, keyboard, network, or tabs - after the contest builds a visualization of activity #### [This is not my tool, but you can find it here](https://github.com/KiK0S/xeppelin) ### 3. What exactly is proposed for Codeforces (implementation, not an idea) The proposal is to use Xeppelin as an external source of behavioral data, without interfering with CF infrastructure. Workflow: 1. The participant launches Xeppelin bef...

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OCPC 2026 Winter — wrap _If you are potentially interested in participating in OCPC **in person** in Summer/Autumn 2026, **please** fill **[this form](https://forms.gle/VdMRh6cAJRN4YvQN6)**!_ Hi everyone! <center><a href="https://ocpc.camp"><img src="https://ocpc.camp/images/ocpc_light.svg" height="80px"></a> <a href="https://icpc.foundation/"><img src="/predownloaded/43/08/43086529a28ccb5c9f2f2eec560ffa85e09c6881.svg" height="80px"></a></center> <center> <b>Supported by</b><br> <a href="https://www.janestreet.com/join-jane-street/open-roles/?type=students-and-new-grads&location=london"> <img src="/predownloaded/ee/f2/eef26616a3661c658d1545f18ed21fabb14d5871.svg" height="40px" style="margin: 10px 10px 10px 10px;"></a> <a href="https://www.hudsonrivertrading.com/"> <img src="https://ocpc.camp/images/HRT.svg" height="40px" style="margin: 10px 10px 10px 10px;"></a> <a href="https://www.silares.com/"> <img src="https://ocpc.camp/images/silares-red.svg" height="40px" style="margin: 10px 10px 10px ...

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ACPC Story 5# "I want to present an objective perspective on why the competition raises concerns, rather than writing a narrative or story. This is based on being a community leader for a year and contestant for 3 years now. 1. Inconsistent and Informal Payment Structure : Payments are handled through external channels, not the official platform. **Some teams pay 25,000 EGP per person (officially qualified), others 50,000 EGP per person (unofficially).** This year for the first time after deadlines, an additional 10,000 EGP per person is charged—an unreasonable variation. 2. Mandatory and Overpriced Accommodation Bundled with Fees : Participants **must pay** fixed accommodation bundled with registration, costing 25,000 EGP per Egyptian student—roughly a semester’s tuition—regardless of personal circumstances. Many could find alternatives for 1% of the cost, yet teams may still pay the full amount even if a member cannot attend, making the policy highly unreasonable and wealth-dependent. 3...

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An Innovative Approach to Productivity/Motivation _DISCLAIMER: This blog is, in all ways, an attempt at humor and in no way should be taken seriously in any manner, nor is it related to CP directly._ #### **Introduction** Hello Codeforces! As a chronically online high school programmer, my daily navigation throughout the World Wide Web is fraught with much temptation and distraction. Having no self-discipline whatsoever, I found myself spending HOURS on [Tetr.io](https://tetr.io/) and [Instagram](http://instagram.com). Rather than solving CF/USACO problems, I would be wasting my life away on meaningless games and reels. #### **Finding a solution** Being an [ABC](https://www.urbandictionary.com/define.php?term=ABC) highschooler, I was consuming my already limited time at an alarming rate. Realizing most of my online distractions came in the form of websites, I turned to online solutions. Specifically, site blockers, to stop myself from reaching these sites. These sites, however, were easily uninstalled, and extremely un...

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Feature Request: Dark/Light Mode Toggle on Codeforces Hello Codeforces community, Many of us spend hours here: solving problems, reading editorials, and participating in contests. While Codeforces is already amazing, there is one feature that would make it more comfortable and modern: a dark/light mode toggle. --- ### Why Dark Mode? * Reduces eye strain during long practice sessions, especially at night. * Matches modern web standards since most competitive programming and developer platforms already have it. * Makes the site more accessible and user-friendly. --- ### Suggested Feature * A simple toggle button in the header or settings. * Persistent choice: the site remembers the last mode you used. * Covers all main areas: * Problem statements * Editorials * Submissions and contest standings * Code editor and tables * Blogs and comments --- ### Why Official Dark Mode is Better than Extensions Some people might say: "Just use Stylus, Tampermonkey, or a browser extension." But an official...

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Codeforces Round 522 (and Technocup 2019 — Elimination Round 3) Hi all! This weekend, at [contest_time:1032] we will hold Codeforces Round 522. It is based on problems of Technocup 2019 Elimination Round 3 that will be held at the same time. Technocup is a major olympiad for Russian-speaking high-school students, so if you fall into this category, please register at <a href="https://technocup.mail.ru/">Technocup 2019 website</a> and take part in the Elimination Round. Div. 1 and Div.2 editions are open and rated for everyone. Register and enjoy the contests! The round was prepared by Alexander [user:Golovanov399,2018-11-17] Golovanov, Evgeny [user:white2302,2018-11-17] Belyh, Alexandra [user:demon1999,2018-11-17] Drozdova, Arsenii [user:senek_k,2018-11-17] Kirillov, Ivan [user:ifsmirnov,2018-11-18] Smirnov, Artem [user:komendart,2018-11-17] Komendantian, Roman [user:Ajosteen,2018-11-17] Glazov, Daria [user:Dashk0,2018-11-17] Kolodzey and me. Huge thanks to Grigoty [user:gritukan,2018-11-18] Reznikov, Ildar [user:300iq,2018-11-18] Gai...

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LLM(large language model) Large Multimodal Models (LMMs) – Detailed Overview 1. Introduction to LMMs Large Multimodal Models (LMMs) are an evolution of Large Language Models (LLMs). Unlike LLMs, which process only text, LMMs handle multiple modalities such as text, images, audio, video, and sometimes even structured data. Their core idea is to unify representation learning across modalities, allowing cross-modal reasoning and understanding. They are foundational models powering systems like GPT-4V (vision), Gemini, LLaVA, Kosmos, Flamingo, CLIP, and ImageBind. The ability to reason over multimodal data makes them crucial for AI applications in robotics, autonomous driving, healthcare imaging, multimodal search, and interactive AI systems. 2. Why Multimodality? Human intelligence is inherently multimodal. We process language, vision, sound, and spatial reasoning together seamlessly. LMMs aim to replicate this ability in artificial systems. A single modality (e.g., text-only) limits...

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Metaverse- Take a leap into the Future Facebook’s decision to rename itself with the new corporate name Meta Platforms Inc. -marked an appropriate endpoint for a year in which the relatively murky concept of the Metaverse became one of the most hyped buzzwords in technology. Many people laughed when Facebook renamed itself, but do you actually know the reason behind it?? Metaverse has set the trend for all internet things so much that it now has its own Wiki definition. Metaverse has already become a part of our lives without us knowing about it. People who play Roblox, Fortnite, Minecraft, etc., are already living in metaverses and won’t likely hesitate to join another where their friends and the things they enjoy all exist. -History: Before understanding metaverse, let us go back to when the internet was invented. British computer scientist Tim Berners-Lee published the first website on August 6, 1991. He dreamt of linking together information with hypertext that could be viewed via a web browser. Years later, he c...

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ACPC Story 2# "I would like to raise a concern regarding the ACPC (Africa and Arab Collegiate Programming Contest). As you may know, this competition is held annually in Egypt for university students across the Arab and African regions. While the event is highly prestigious and academically valuable, many participants have expressed serious concerns about the participation fees. Despite the fact that the contest is supported by multiple sponsors, the cost required from each team has become extremely high—reaching around 2,000 USD per team. This amount places a significant financial burden on students and creates a situation that feels exploitative, especially considering that the competition is intended to encourage and support young talent, not limit their opportunities. Such excessively high fees can be viewed as unfair, and they risk undermining the purpose and spirit of the competition. We strongly believe that a reassessment of the fee structure is necessary to ensure fairness, accessibil...

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Add a "next problem" and a "previous problem" button. when you're in a contest and the site is overloaded and requests take a long time and you already live in an area with bad internet like me, and you want to go to the next problem with a single click you need to either have the main problems page open so you can open any one quickly or have the complete problem set open. I think it would increase accessibility if there was a convenient way to go to other problems within a specific problem page. a drop down menu is also good that allows you to go to any other problems, not just the next/previous one. what do you think? have this thought crossed your mind before?

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“Division 5: Helping Beginners or Hurting Codeforces?” Should Codeforces Have a Division 5? When I first joined Codeforces, Div. 2 felt like climbing Everest without training. Many beginners open a contest, see the problems, and quit before they even enjoy the platform. It made me wonder: what if there was a Division 5 — a safe space for absolute newcomers? Why Div. 5 could help Confidence building: Newcomers could solve problems without the pressure of competing against Div. 2 regulars. Accessibility: Problems could be closer to “first steps” in programming contests — sorting, simple loops, basic math. Community growth: More beginners might stay active, eventually moving up to Div. 4 and Div. 3. Comparisons Other platforms already do this: AtCoder has Beginner Contests. LeetCode weekly contests often start with very approachable problems. These formats show that beginner‑friendly divisions can work well. Open question Would a Division 5 (or something similar, like beginner‑only practice rounds) make Codeforces ...

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Discussion: Do you think there'll ever be a new Olympiad for Machine Learning/AI Seeing as how today CS has expanded beyond "classical informatics", do you think there'll ever be an IOML? I find it very unlikely that the IOI would compromise, and that's a good thing since we need to keep the algorithmic tradition alive in a world where every industry is hunting for "black box" solutions. And yet, AI and its varieties are gaining only more attention and accessibility. Not to say that there aren't already a ton of competitions (even for high school students), but I think it could be very nice if we had a premier international competition. Any thoughts or ideas?

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Tutorial: How to fix broken Codeforces Latex Display 2 . Right click on any Latex and it will provide a settings interface. 3 . Enter Math settings → Math renderer option 5 . Try each option until it displays normally. 7 . If it still doesn't work, try close Accessibility → Assistive MathML 11 . Don't forget to thank me :P

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What is the minimum contribution on codeforces?? I want to know what is the minimum contribution one can have on codeforces. I am currently at -68 , is there anyone with less contribution than this? Also does having negative contribution affect the accessibility of features on codeforces?? Can the community help me beat r_pi in negative contribution. Come on it's time for a change. bring those downvotes assholes xD

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