Hello, Codeforces! We, Algolymp, are a team of competitive programmers from Romania, and we’ve been working on Codeforge, a multiplayer game built around solving algorithmic problems. Special thanks to munteanuvlad98 for coordinating this project.

The idea is simple: take the problem-solving we enjoy and give it more ways to be played together. Challenge a friend, compete as a team, enter a knockout tournament, or work through daily problems on your own.

What can you do in Codeforge?

• Solve daily challenges. Problems range from beginner-friendly exercises to IOI/ICPC-level challenges, whether you’re learning your first algorithms or preparing for your next contest.

• Play individual or team battles. Go head-to-head with another player, or team up with friends and compete against another team.

• Enter knockout tournaments. Compete individually or as a team, with each round deciding who advances.

• Build a community. Bring together your school, programming club, or friends to train and compete.

• Earn Algocoins. Spend them on merchandise, video games, or in-game items that can help you in battles.

• Create your own competitions. Organize an algorithmic contest for your community or challenge a group of friends.

What about cheating? A close battle isn’t much fun if you can’t trust the result. Codeforge includes an AI-powered anti-cheating system designed to detect unfair play and help keep progress and competitions fair.

Help us make it better Whether you’re a beginner or an experienced contestant, we’d love to have you try Codeforge. Tell us which formats you enjoy, what feels off, and what you’d like to see added.

Pre-register for Codeforge here to join us when we launch on October 12.

Questions, suggestions, and criticism are welcome in the comments. See you on October 12!

UPD: Codeforge is now open!

Hello, codeforces!

We are holding the first round of the RoAlgo Cup in less than 24 hours!

About RoAlgo and RoAlgo Cup

RoAlgo is the biggest algorithmic community in Romania, with over 3000 active members. The RoAlgo Cup is an open competiton held by members of this community. This is the first round and is expected to be enjoyable and educational in the rating range [pupil, grandmaster], featuring 8 problems roughly sorted by difficulty. The authors of this round are SSKMF, RaduM and Alex Mihai Ioan.

The contest will be held on kilonova, link to the contest: here. The starting time is 13 UTC on the 8th of February and the duration is four hours. Hope to see you in the standings!

Hello! Today, I virtually participated in BalticOI 2015 day 1 and had quite an unpleasant surprise concerning task 1 (bowling). I had two solutions for it, one that took around 2e8 operations on the worst case but also on the best case, and was quite independant on the subtasks, and one that maybe could get to 2e9 operations or something but with a very good constant factor. The first one scored 0 on cses, while the second one scored 42. After the contest ended, I wanted to see the running times of my sources and submitted them on oj.uz, and guess what: the first one took 39 points, while the second one took 82, failing on test 96. The exact same source codes. Now, of course I wonder, what would have my score been during a contest? And I can't stop thinking: "should I consider that I solved this problem for 82 or for 42 when considering my virtual participation"? I think this is actually something that might have happened to many coders throughout the years.

I see this as a problem with a very simple solution: adapting the time limits according to each online judge's capacities. For instance, take the model code's running time on the contest server and get the ratio between it and the time limit. Then, set the time limit on the online judge as to have the same ratio. For instance, I assume that in the example I gave, if the contest was held on CMS with a 1s time limit (I just suppose, correct me if I'm wrong), then probably the TL should have been a bit bigger on oj.uz (like 1.2 s) since I think it works a tiny bit slower (again, correct me if I'm wrong, this is my personal experience) and maybe 1.5 or 1.4 or something on cses since it is clearly slower. If every OJ did this, the virtual participations would be much more appropriate, and there wouldn't be such huge 40p differences between two different ones.

Thanks for reading and please, if you are an OJ admin, consider this when setting your time limits!

Hello, codeforces! I am writing this blog as a new idea to improve the website, sorry if it has appeared before. Sometimes, you're not in the mood to participate in a contest and fully focus, but you would like to "casually" participate without rating change, or maybe you want to participate but you are a bit late, etc. Currently, you don't have a very good solution in any of those cases, because you either don't participate, or you participate with a high chance of losing rating points. A very simple solution would be to be able to register unoficially for the contest, no matter your rating. What do you think?