Hello Codeforces!

Following up on our initial announcement, we are excited to share that the Practice Phase for the IIMOC × FrontierCS 2026 Global Optimization Marathon is now officially open!

The practice problems are a curated subset of the FrontierCS benchmark designed to help you set up your local environments and testing pipelines, understand the relative scaling (0–100) scoring system in action, and test your submissions.

Head over to iimoc.org to access the practice datasets and evaluation infrastructure, the real contest starts May 1.

Hello Codeforces!

Following the massive success of IIMOC (International Math Optimization Challenge) 2025, which saw over 200 teams and 9,500+ iterative submissions, we are back with something significantly more ambitious. This year, IIMOC is moving from a standard contest to a month-long, research-grade optimization marathon.

About IIMOC x FrontierCS

The IIMOC is a global high-school contest focused on heuristic problem solving. It is problemset by the FrontierCS team, a PHD research team of former competitive programmers, including CP legends and problemsetters like zhoukangyang and ZhouShang2003.

Teams from around the world are invited to tackle a single large-scale optimization problem that is intentionally approachable but unsolvable in exact form. Over the course of one month, each team develops algorithms and heuristics to minimize loss and maximize performance.

Dynamic Scoring and "King of the Hill"

We have designed a scoring system that rewards both peak performance and consistent innovation:

• Relative Scaling (0-100): Every problem is scored relative to the current Global Best. If you hold the world record, you have 100 points. If someone else pushes the frontier further, the "ceiling" rises, and all other scores are scaled down in real-time.
• The "King of the Hill" Bonus: To reward those who set the pace and prevent "last-minute sniping," every day, teams will receive bonus points for each problem based on their current placement.

Prizes and Global Distinction

With a unified leaderboard, the competition will be at an all-time high. We are awarding:

• Official T-Shirts: For the Top 3 teams globally.
• Gold Distinction: Top 10% of the leaderboard.
• Silver Distinction: Top 20% of the leaderboard.
• Bronze Distinction: Top 30% of the leaderboard.
• Participation Award: Anyone who submitted a non-zero score solution.

Team Logistics

• Max 4 members per team.
• Open to everyone (Unified Division).

Schedule

Technical Infrastructure

This season is made possible by our lead sponsors, AP Memory and CascadeX. Their support provides the high-performance infrastructure required for a month-long, iterative grading marathon.

For those who want to get a head start on the environment, check out the general benchmark and evaluation infrastructure on the FrontierCS GitHub.

• Problems Prepared by: FrontierCS Team
• Testers: FrontierCS Team and IIMOC Team

Register: iimoc.org

See you on the leaderboard!

Hi Codeforces,

Yesterday someone spammed the IIMOC endpoints with thousands of requests, causing the server to crash. We have removed all fake submissions and added security features so that this will not happen again. Ordinary users will not be affected by these security issues.

The website is now again functional.

Hello everyone!

We are excited to announce that the International Invitational Math Optimization Challenge (IIMOC) 2025 has officially begun!

IIMOC is a month-long algorithmic optimization contest featuring a single NP-hard optimization problem, designed for competitive programmers, university teams, and advanced high-schoolers. This year’s edition already includes signups from MIT, HKUST, top IITs, and dozens of other universities and national Olympiad teams.

Contest dates: November 22 – December 21, 2025

Signups remain open throughout the competition. You can register anytime at https://iimoc.org — the process is quick and requires no verification. We encourage new teams to join; most teams haven’t submitted yet, and losing a few days makes very little difference in an optimization-style contest.

We hope your heuristics converge faster than the submission deadline!

EDIT: Contest ends December 21, 9:00PM PST exactly.

你好Codeforces!

The International Invitational Math Optimization Challenge (IIMOC) team is pleased to announce the start of the 2025 season of IIMOC.

About IIMOC

The IIMOC is a global high-school contest focused on heuristic problem solving. It is problem-set by ZhouShang2003 (Real Contest Problem), Joyemang (Sample Problem) with help from Berkeley Sky Labs and advised by Rob Kolstad (former head coach of the USA Computing Olympiad). Problems were prepared by Edwin Chen. It is tested by just_average_ok, ZhouShang2003, Marco_L_T, Torin Solmer, Reece Hanchett, Chris Bartlo, and many others from the Lincoln Computer Science Association.

Teams from around the world are invited to tackle a single large-scale optimization problem that is intentionally approachable but unsolvable in exact form. Over the course of one month, each team develops algorithms and heuristics to minimize loss and maximize performance.

Contest Highlights

Open internationally: Any high-school/observer team can participate.

One deep problem: No short puzzles; you spend the month refining your solver.

Real-world: Optimization, data analysis, and creative algorithms.

Visualizable: The problem will contain a visualizer for seamless debugging.

Professional Development: High-ranking teams may be recommended to sponsors.

Transferrable Skills: The problem will contain algorithmic aspects, so those who are confident on Codeforces will also find success in IIMOC.

Prizes

The winning team will receive a trophy and some t-shirts as a Souvenir. There is no limit on team sizes but only up to 30 people will receive a t-shirt.

Timeline

There is no deadline for registration; In other words, registration will continue to be allowed until the submission deadline. The competition will proceed as follows:

Nov 22, 2025 Competition begins, problem released

Dec 21, 2025 Submission deadline

Dec 22, 2025 Results released

Divisions

There is a high-school contest, in which anyone below the age of 18 can participate. Contestants above the age of 18 can put "observer" under "What country is your club/team located in?". This division will also recieve T-shirts, but note that the maximum team size is 10.

How to Join

Registration and rules are available on our website: iimoc.org

Form your team, read the challenge, and start building your heuristic!

Sample Problem

IIMOC will feature a problem with similar style to AtCoder Heuristic Contests, except with more math involved and a more approachable problem. We provide a sample problem for teams to get used to the logistics before the contest start on November 22. You can access this problem here.

Our Sponsors

We are sponsored by AP Memory and Cascade-X. AP Memory is a company based in Taiwan working on VHM technologies with wide applicability in AI and High Performance Computing; Cascade-X is in stealth mode.