On-Line Contests

The USACO holds web-based algorithmic programming contests during the academic year, usually four total, from December through early spring, one per month. The final contest is the US Open, carrying more weight and serving as our national championship exam. Contests usually run for four continuous hours in length for a normal contest, and five for the US Open. For maximum flexibility, you are free to schedule this block of time anywhere within a Friday-to-Monday contest weekend --- your timer starts when you log into the contest and download the problems. Contest tasks are presented on the web, and you submit your final solutions through a simple web interface.

Participation is free and open to all. Pre-college / USA students are typically ranked separately from "observers" (all others participating). There is no pre-registration required to compete; all you need is an account on this site. During the Friday-Monday timeframe of an active contest, a button will appear on our homepage that will take you to the contest page, where you can see additional details about the contest and click another button when you are ready to start.

Contests are offered in four divisions:

• Bronze, for students who have recently learned to program, but who have no training in algorithms beyond basic concepts like sorting and binary search.
• Silver, for students who are beginning to learn fundamental problem-solving techniques (e.g., recursive search, greedy algorithms) and fundamental data structures.
• Gold, where students encounter more standard algorithms of a more complex nature (e.g., shortest paths, dynamic programming) and more advanced data structures.
• Platinum, for advanced students who are well grounded in algorithmic problem-solving techniques, who wish to challenge themselves with sophisticated and more open-ended problems.

All participants start in the bronze division, and those who score particularly well in a contest will be promoted to the next division. Contestants with a perfect score will be automatically promoted to the next division while a contest is running; in this case, if interested, they can click to start the contest in the next division (with a full clock) during the same Friday-Monday timeframe. Others will need to wait until results are announced at the end of the contest to see if they meet the (contest-dependent) cutoff for promotion.

Detailed technical specifications and rules for our contests are available here.

An archive of many years worth of historical contest problems is available here. These come with solutions and the ability to submit code to have it judged for correctness. If you have never competed in a USACO contest, you may want to practice with a few of these problems first, in order to gain some familiarity with problem style and the submission system on this site, before embarking on a timed contest.

Note that we have recently introduced the notion of a certified contest result for some divisions (currently platinum and gold), obtained by taking the contest in a specific common time window when problems are first released. In these divisions, problems will be first released at 12:00pm (noon) eastern time (ET) on the Saturday of the larger Friday-Monday contest timeline. Any student who begins the contest in these divisions between 12:00pm and 12:15pm ET on that day will receive a certified score, treated by USACO staff as having higher potential credibility and weight than a non-certified score. A certified result is required for promotion from gold to platinum, and at least 3 certified scores are required for consideration as a finalist invited to our summer training camp. If you are competing in bronze or silver, do not worry yet about this extra complexity, as certified results do not apply to those divisions; bronze and silver contest problems are available during the entire Friday-Monday timeline.

The Road to the IOI and EGOI Teams

Based on the results of the web-based contests throughout the year (with particular emphasis on the US Open), approximately two dozen students are invited as "IOI finalists", to a rigorous academic training camp in the early summer, hosted at Clemson University, culminating in the selection of 4 of them to represent the USA at the International Olympiad in Informatics (IOI). Joining them at camp are a cohort of top female USA students, invited as "EGOI finalists", who are selected according to the same criteria and who participate in the same training program. These students, along with any female IOI finalists, are contending at camp for positions on the 4-person team to represent the USA at the European Girls' Olympiad in Informatics (EGOI). The IOI and EGOI are held in different countries every year and are generally regarded as being among the most prestiguous computing contests in the world at the pre-college level. At camp, many more contests, advanced lectures, and a full schedule of additional computing-related and extracurricular activities fill out the week of activities.

To be eligible for selection as an IOI or EGOI finalist and ultimately as an IOI or EGOI team member, you must be enrolled in a high school (or junior high/middle school) for at least one semester in the school year before the IOI / EGOI. You can concurrently take courses at other institutions, including colleges and universities. You must either be a US citizen or a resident of the USA during the first half of the school year. IOI team members from countries other than the USA are not eligible to be USACO finalists (and this includes students who have made commitments to other countries that could conceivably result in their being selected for an IOI team prior to USACO camp).

To be selected as a finalist, you must excel in your participation in USACO web-based contests through the year. Students in their senior year, and finalists from previous years generally face a stricter set of criteria for selection than younger / newer students. Students who miss contests during the year are also potentially at a disadvantage in terms of competitiveness.

Expenses for the USACO training camp are paid by the USACO, although participants are asked to fund their own transportation to the camp. For the IOI and EGOI, all expenses, including transportation, are paid by USACO. We are immensely grateful to our sponsors for allowing us to support these activities.

Your Account

2024-2025 Schedule

Dec 13-16: First Contest
Jan 24-27: Second Contest
Feb 21-24: Third Contest
Mar 21-24: US Open
For each contest, USA students
wishing to receive a certified
score in the platinum or gold
contest must start Saturday at
12:00 ET, when problems in those
divisions will be first released
(see contest details for
more detailed instructions)

May 22-31: Training Camp
Dates TBD: EGOI (Jul 14-20, Germany)
Dates TBD: IOI (Jul 27-Aug 3, Bolivia)