Hello Codeforces!

We are excited to invite you to compete in CALICO Spring '24! The contest starts Saturday, April 27, 2024 at 4:00 p.m. PT and will be 3 hours long. Registrations are now open and will be until April 24, 2023 at 11:59 p.m. PT, so register here while you can! The contest will take place on our custom judge platform and for the first time, contestants can compete online or in-person at UC Berkeley!

In-Person Contest (New!)

The CALICO team is proud to announce our first in-person contest ever—that's right, CALICO will be happening LIVE at UC Berkeley! We’ll be providing in-person contestants with exclusive merch, dinner, and opening/closing ceremonies with live guest speakers. This is also an excellent opportunity to explore the UC Berkeley campus, meet the team, and make new programming friends! If you’re interested, be sure to fill out this additional form in addition to the main registration form.

About

The California Informatics Competition (CALICO) is a semiannual team programming contest organized by students at the University of California, Berkeley. We create original problems to encourage students to grow their problem-solving skills and learn algorithms in fun and exciting ways. Check out our website to learn more about the contest and join our discord server to get announcements, make teams, hang out, and more!

Contest Info

The contest will be 3 hours long and you can compete solo or in a team of up to 3. There will be around 8-12 problems spanning a wide range of difficulty for all skill levels. Some problems will have bonus test sets, where more efficient or advanced solutions can earn additional points. At least one of the problems will be interactive. Anyone can compete, but only pre-college teams will be eligible to win prizes. Editorials for some problems will also be available after the contest. More details will be released as the contest date approaches.

Credits

These awesome problems and editorials are written, prepared, and tested by the CALICO Team, including Bungmint, plourde27, yjp20, bradley.louie1, EJam, spiralsim, Gotheru, ss1237, mudkip, fatant, alfphaderp, vcivek, voidcs, JayU_, skywire2000, and many more!

We’ve had a ton of fun creating these problems! We think there will be something interesting for everyone, regardless if you’re totally new or an experienced competitor.

Good luck on the contest!

Link to English flyer | Chinese flyer

Hi Codeforces!

Thanks to the 76 people who came in person to the Bay Area Programming Contest this year, and of course our 29 virtual teams!

The contest has been uploaded to the gym here, and is available for virtuals or upsolving.

We hoped you enjoyed the problems as much as we enjoyed organizing! Please let us know in the comments if you have any questions or concerns.

UPDATE: the model solutions (and some extras) to all problems are posted at this link.

UPDATE: written editorial is now available here.

Hi Codeforces,

Gunn High School's competitive programming club will be hosting the Bay Area Programming Contest on March 3, 2024. You can find our website, with detailed information, at bapc.gunncpc.com. You can register for the contest at this link.

Problems were set by ezraft, GusterGoose27, lce4113, and Ench_Lolz with help from BucketPotato and qpwoeirut.

Thanks to our testers: willy108, izhang, Jasonwei08, flamestorm, amsraman, eggag32, EnDeRBeaT, NightWizard777, Feet_McYeet and especially to myst-6, omeganot, and Benq.

Time and place

The contest will be held in-person at Gunn High School. It will start at 12:30 PM local time. Click here to see the exact time in your timezone.

We will be providing free lunch for in-person participants. People who can't make it in person can participate in an online mirror.

Contest format and rules

Both the in-person contest and the online mirror will be held through DOMjudge. The contest will be 3 hours long, with 8-16 problems. Scoring will be ICPC-style.

Participants can form teams of up to three people. In-person participants are allowed one computer per team. Regarding use of the internet and similar, we will be using the same rules as the USACO-- in particular, participants may only look up basic information about their programming language. Templates, OEIS, generative AI, Codeforces blogs, and similar are not allowed. Teams will be given a printed copy of KACTL.

Online participants do not need to follow these rules, since we have no way of enforcing them.

Check the website for more details.

Prizes

Prizes will only be available for in-person precollege teams. More information will be added soon.

As the title suggests, there will be a lockout tournament targeted towards pre-college students, organized by (in no particular order) lethan3, ezraft, PurpleCrayon, GusterGoose27, Apple_Method, codetiger927, qpwoeirut, clcos, jamster, and izhang.

Timing

The opening ceremony will start April 29 around 10:30 AM Pacific time (click the link to see the converted time), where tournament specific rules and the structure will be announced.

It will last for an expected 4 hours. You can check the website for more details.

All problems for the lockout matches will come from the Codeforces problemset, so the starting time may be modified depending on how fast system tests for round 869 go.

Who can participate?

The main tournament is intended for precollege participants.

Non-precollege participants can join to spectate or play some casual matches.

How to participate?

Join the Discord server. Also see the website for more information.

Format

Double-elimination.

Again, for more details, please visit the website or join the Discord server. Most logistics will be handled through the latter.

Also, SecondThread will be streaming and commentating the tournament! The link will be added here tomorrow.

Update

We would like to congratulate the winners of the Lockout Tournament Official (Pre-College) Division:

1. Dominater069

2. amoeba3

3. skittles1412

4. oursaco

5. Adam_GS

6. hazzler

7. debugging_since_epoch

8. Ina

And we would like to congratulate the winner and the only present participant :flushed: of the Unofficial Division:

1. ScarletS

Check out the recording of the livestream here!

Thank you, participants, for such a successful tournament! We hope you enjoyed dueling with us and had fun!

Some stats about the round

Solutions

Problem A

Problem B

Problem C

Problem D1

Problem D2

Problem E

Hi Codeforces,

We're excited to invite you to Codeforces Round 809 (Div. 2), which will take place at Jul/18/2022 17:35 (Moscow time). All problems were created and prepared by lunchbox, lce4113, and me. It will be rated for all participants with ratings lower than 2100.

Thanks to the people that made this round possible:

• IgorI for coordinating the round, patiently guiding us through the preparation process, and translating all statements to Russian.
• KAN, for guiding and assisting IgorI in the coordination.
• Apple_Method, izhang, lethan3, moo., null_awe, and ezraft for proposing problems that didn't make it to the final version of the round.
• PurpleCrayon for feedback and suggestions in the early stages of the round.
• Our testers, for their time and feedback: EnDeRBeaT, Queue, AlperenT, FairyWinx, ak2006, TheScrasse, sus, SirPh, litesam, asrinivasan007, Igorbunov, Runtime-Terr0r, timreizin, and Aaeria.
• MikeMirzayanov for the excellent platforms Codeforces and Polygon.

You will be given 2 hours to solve 5 problems, one of which will be divided into 2 subtasks. The scoring distribution will be announced later.

UPD: The scoring distribution will be $$$500 - 1000 - 1250 - (1000 + 1250) - 2250$$$.

UPD2: The editorial has been posted at https://codeforces.com/blog/entry/105008.

UPD3: Winners

Official

1. WYZFL
2. c8k
3. tiger1926
4. b6e0
5. iztrax

Everyone

1. tourist
2. SSRS_
3. WYZFL
4. Rubikun
5. noimi