California Informatics Competition (CALICO)

Recommend for students who are taking AP computer courses or applying for STEM majors in university of the U.S.

Junior & Senior Division, different ranks suitable for students with different programming levels

Sponsored by Meta, Microsoft and other advanced technology companies

Team work, solving interesting problems with team collaboration

Preparatory challenge for USACO (USA Computing Olympiad)

Suitable for junior and senior high school students

Past papers are available for preparation

November 19, 2023 08:00 am


California Informatics Competition (CALICO) is hosted by the Open Computing Facility (OCF) at the University of California, Berkeley. The standout feature of this challenge is its close alignment with the renowned computer science courses at Berkeley, including CS61A (Introduction to Computer Science), CS61B (Data Structures and Algorithms), and CS170 (Computer Science Seminar). By participating in this challenge, students can gain a deeper understanding of computer science and feeling of the University of California, Berkeley.

The goal of CALICO is to promote the understanding of useful algorithms and encourage students to grow their problem-solving skills. The distinct feature is that the difficulty of the questions incrementally increases, including basic programming concepts and university-level programming content. We highly recommend students planning to participate in the USACO (USA Computing Olympiad) or studying AP computer courses, as well as students considering applying for STEM programs in the U.S. as their major to participate.

Official Website:

Challenge Rules


Chinese & English

Programming Language: 
  • C
  • C++
  • Java
  • Python3

November 19, 2023 8:00 am (3 hours)




Junior and Senior high school students. Categorized into Junior Division and Senior Division, with the option to form cross-grade teams; if there is 1 high-school student in a team, it is considered a Senior Division team, and awards will be evaluated accordingly.


1-3 students per team (Recommend 3 students)

Problem Ranks:
  • Rank 1: Problems should require knowledge of introductory programming concepts (conditions, loops, etc.).
  • Rank 2: Problems make use of introductory algorithmic concepts & data structures, involving more problem-solving than Rank 1's.
  • Rank 3: Problems may use algorithms or math concepts taught at UC Berkeley, and involve more logical complexity. These problems also typically require some degree of computational efficiency.
  • Rank 4: Problems are typically extremely involved, open ended, and rely on a combination of problem-solving and advanced concepts.
  • Bonus problems : a fifth category, are not assigned a rank; rather, they are paired with existing contest problems. They only differ in terms of the input size or introduce more logical complexity.

*The majority of problems in a CALICO contest will be Rank 2 and 3, with the bulk being Rank 2. There will only be a few Rank 4 problems.


Global Awards
  • TOP1-TOP5

(Team work, Junior & Senior divisions are ranked together)

National awards
  • 1st, 2nd and 3rd place
  • Gold: Top 10% Teams
  • Silver: Top 20% Teams
  • Bronze: Top 35% Teams
  • Honorable Award: Top 50% Teams

(Team work, Junior & Senior divisions are ranked separately. Award announcement date will be determined later.)

Past Papers

Registration Deadline

November 15, 2023

Sample Problems


1. How much programming experience do I need to compete?
If you know how to work with conditions, loops, strings, and integers, you can start solving problems! At a higher level, our problems give students a preview into concepts taught at various classes within Berkeley's CS department. Regardless of whether you're just starting out or a seasoned programmer, there will be something for you!
2. programming language
  • C
  • C++
  • Java
  • Python 3
If, for some reason, the student is unable to attend after paying the fee, please contact us. If you apply before the registration deadline, 25% of the registration fee will be deducted as academic materials and service fees. If you apply after the registration deadline, no refund will be given.
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