Welcome to USACO 2005

 Alex Schwendner, Eric Price, John Pardon, Richard McCutchen
2005 USA Computing Olympiad Team  with four gold medals at IOI in Poland.

This year the USACOconducted five Internet contests, the US Open, and the summer training camp and final round. The summer training camp as held at  Colorado College in Colorado Springs, Colorado. Sixteen students will be invited by the USACO committee.  The USA Team won four gold medals at the 17th IOI in Nowy Sacz, Poland, Aug 18-25, 2005. The team chosen is shown on the left.


Internet Contests


The biggest new competition item this year is the contest names and levels. We intend to run contests for the entire gamut of programmers, from those taking their first course through the international level challenges we've held for years.  Here are the divisions and the general levels they represent:

Below is this year's schedule for the Bronze, Silver, and Gold contests. Novice contests will run on a different schedule. Contest lengths are not shown because we choose the length based on the problems the contest contains. Except for the US Open, which is proctored and held on a single day for USA contestants, contests run from Friday morning until Tuesday morning, USA Mountain Time:

The elite level with the most difficult challenges. The lowest-level competitors in this division should be able to create a dynamic programming algorithm from scratch (similar to the old Green division).

Just below the Gold division, Silver competitors should know a number of standard computer algorithms (e.g., the flood-fill algorithm). Silver is similar to the old Orange division.


Students who can write programs that work, including ad hoc programs that don't require fancy optimized algorithms.


For first year students. Problem levels escalate through the year in parallel with standard instructional curricula. Contests will be one hour in length and are intended to be administered during class.

The USACO is open to:

* All pre-college students throughout the world with access to the internet are eligible (except cheaters who have been banned)

* No fees are charged

* Contest languages include C, C++, Pascal, and Java

* Contests beyond the first-year level are three to five hours in length

* Cheaters are banned for life

* Results are widely disseminated and reported on the USACO web site

* The 'big prize' is an invitation to the USA Invitational Competition (name still pending) in Colorado Springs, CO in the first half of June, 2005.

* The 'biggest prize' is membership on the four-student USA international traveling team that will represent the USA in Poland at the International Olympiad where 80 other countries will also compete in August, 2005.


  • Nov. 5-8, 2004 :
    The USACO  Qualifying Exam. This contest will be the three hour contest that is expected to feature five or six problems. The tasks and scoring are anticipated to facilitate placement of competitors at the proper level. Not all competitors will solve all problems. It is possible (after subsequent contests) to be invited to move down a division if it is clear that the contestant is miss assigned.
  • http://ace.delos.com/contestgate
  • Dec 10-13, 2004 :
    The USACO December Contest is open to all pre-college students who have access to the Internet.
  • http://ace.delos.com/contestgate

  • Jan 14-17, 2005 :
    The USACO January Contest is open to all pre-college students who have access to the Internet.
  • Feb 11-14, 2005:
    The USACO February Contest is open to all pre-college students who have access to the Internet.
  • March 18-21, 2005 :
    The USACO March Contest is open to all pre-college students who have access to the Internet.
  • Registration:

    Registration at http://ace.delos.com/usacoregister (for both contests and training)


Both Gold and Silver levels are "invitation-only". Invitations are earned by:

* Doing well on the November 5-8 qualification exam

* Doing well at the Bronze or Silver Level on subsequent contests

* Special cases as determined by the coaches




Registration Training Materials
For both contests and training is at:




The USACO training pages at http://train.usaco.org are still available free of charge for anyone who wishes to practice.

While we have supported Java in programming contests for almost a year now, we are pleased to announce that THE TRAINING PAGES AT http://train.usaco.org NOW ALSO SUPPORT JAVA (though you have to do an extra click for the 'experimental grader' until it's solid).

U S Open


The USACO U S Open is a five-hour proctored competition that is conducted at local high schools under the direction of a local coordinator. A 2005 USACO U S Open and International Champion will be selected. 
  •  April 28  for USA participants.

  •  April 29-May 2 for non-USA participants.


First USA Invitational Computing Olym


The USAICO  consisting of 14 US finalists and 8 foreign competitors will be held at Colorado College. From the US finalists, four students will be chosen to represent the USA at the 17th IOI in Nowy Sacz, Poland, Aug 18-25, 2005.


  • June 1-9, 2005

Criteria For 2005
We will use all contest results and work on the training materials as evaluation criteria for choosing attendees at the USACO training camp to be held in June, 2005. 
This means that candidates who show long-term strength (and/or growth) are more likely to be chosen for camp than those who have one lucky contest. We will be keeping a record of all  progress on the training materials.