December 2019 Contest Details

The USACO 2019 December contest is available December 13 through December 16. Participation is free, and open to all, although only high-school (pre-college) students in the USA are eligible for selection as finalists to attend the USACO training camp and to compete for the USA IOI team.

The contest is available in four divisions: bronze, silver, gold, and platinum. All returning participants start out in their former divisions, and new participants start out in the bronze division. The contest is for individuals only, not teams.

Participants who score particularly well in their current division will be promoted to the next division for future contests (promotion criteria is announced at the end of the contest and varies on a per-contest basis, since every contest is different). Promotion within a contest is also possible, if you achieve a perfect score. If you are promoted within a contest, you will be able to take higher-level contests with a full clock (no penalty based on the time already spent on ealier contests).

Each contest has 3 problems to which you will submit solution programs in C, C++, Pascal, Java, or Python. Problems are algorithmic in nature, and your score for each problem depends on the number of input cases your program can solve within the time limit (for this contest: 2 seconds per input case for C, C++, and Pascal, and 4 seconds per input case for Java and Python). If your program correctly solves the sample input case (included in the text of each problem), you will receive feedback on how it performs on each of our judging inputs. For example, you will be told if your program produced the right answer, timed out, experience a run-time error, etc. Note that although you receive this feedback, the remaining judge inputs beyond the sample case are not disclosed during the contest. Problems are intended to be challenging; it is rarely the case that a large number of competitors receive near-perfect scores!

The contest is 4 contiguous hours in length. You can take the contest during any 4-hour block of time you want, as long as you start during the larger contest window starting the morning of Dec 13 and ending Dec 16 at 23:59 UTC-12 time. When you start the contest, your personal 4-hour timer starts counting down, and you will be able to view the contest problems and submit solutions via this website.

Results will be posted on this website shortly after the end of the contest.

Instructions and Rules

Detailed contest instructions and rules are available here. Please read them if you have not already done so. Note that if you program in Java, there are special requirements to follow (e.g., submitting your entire program in one file), which are outlined in the instructions. Please email the contest director ( if you come across any technical problems.

Language Availability

The contest is currently available in the following languages: en, ru, es, fr, zh (bronze and silver), mn (bronze, silver, and gold), hy (bronze).
Additional translations may become available later in the contest.

Getting Started...

You are not logged in. If you haven't created a USACO account yet, you may want to go ahead and do this. You need to be logged into your account to participate in the contest.

Your Account

Not currently logged in.