It's been a while since we've posted an update on what we've been working on, so we felt it was about time for one.

New Runtimes

We've updated several runtimes, the big changes being:

• GCC 14 → GCC 15, and C++23 is now available.
• Clang 19 → Clang 21, and C++17, C++20, C++23 are now available on Clang.
• Groovy 4 → Groovy 5
• Intercal has been removed
• Java 22 → Java 25
  • This also affects the JVM-based languages (i.e. Groovy, Kotlin, Scala)
• Lean 4.19 → Lean 4.28
• Node 20 → Node 22
• NASM 2 → NASM 3
• OCaml 5.0 → OCaml 5.4
• Rust 1.87 → Rust 1.94
• Scala 2 → Scala 3.8, many thanks to Kirito for the help!
• Zig 0.6 → Zig 0.15, many thanks to d for the help!

We have locked all previous Zig and Scala submissions. If a problem where you have submitted in Zig 0.6 or Scala 2 is rejudged, your submission will no longer count for points.

All problems from this year's CIW have been added. You may access them here.

Unofficial mirrors for day 1 and day 2 have also been set up.

All problems from this year's CCC have been added. You may access them here.

An unofficial mirror for the junior and senior contests have been set up.

Editorials for problems will be added once they are published by the CEMC.

Hope you enjoyed this year's CCC!

Aloha all!

After an ambitious and arduous assembly, an Advanced Algorithmic Assessment appears!

The contest will begin on December 18th, 2025 00:00 EST and will last one week. Participants will have a 3 hour window to solve 6 problems.

The contest is rated for participants with a rating less than 2800.

For more information, please visit the contest page.

Awsome activities and amazing adventures await!

All problems from day 1 of and day 2 IOI '25 have been added. You may access them here.

An unofficial mirror for day 1 and day 2 of the contest have been set up.

The problem statements and data were uploaded by X_Ray and published by maxcruickshanks.

Finally, we wish to congratulate team Canada for their amazing performance at IOI!

• skittles1412 - achieving 7th place and IOI Gold,
• littlecat - IOI Silver,
• Tarek Zaki - IOI Bronze,
• Alex Lin - IOI Bronze!

You can see the results here.

All problems from this year's CCO and CIW have been added. You may access them here and here, respectively.

Unofficial mirrors for CCO day 1, CCO day 2, CIW day 1, and CIW day 2 have also been set up.

The problem data were uploaded by BalintR, the problem statements were uploaded by Kirito, and the mirrors were made by maxcruickshanks.

An unofficial scoreboard for CCO is accessible here compiled by AustinJiang.

Finally, congratulations to littlecat, skittles1412, Alex Lin, and Tarek Zaki, who will be representing Canada at the IOI!

Hi everyone!

This Thursday, we'll be hosting the end-of-school-year OTHS Coding Competition!

The contest will be unrated. For more details, check out the contest page.

Have fun!