The winner of the regional contest is the team that solves the most problems. If two or more teams solve the same number of problems, the team with the shortest total elapsed time is the winner. If two or more teams are still tied based on elapsed time, the following tie-breakers will be applied, in order, until the tie is broken.
The first three criteria are objective, and the fourth is subjective. All of the criteria are independent of the specific language, computer, and operating system used, although program length may vary slightly depending on the choice of language.
Each of these criteria is applied on a per-problem basis. Using algorithm efficiency as an example, if Team A has two solutions that are more efficient than Team B's, one solution that is less efficient than Team B's, and three solutions that have the same efficiency as Team B's, then Team A would be the winner.
Asymptotic algorithm efficiency. This is the running time of the program as a function of the input size n, expressed using the standard "big-O" notation.
Generality. This refers to the ability of a program to handle test cases beyond those specified in the problem description. For example, the description might say that there will be at most 100 inputs, but the program can actually handle any number.
Length of program. This is measured by the number of executable statements, not necessarily the number of lines in the program. Teams can use comments and whitespace freely without risk of being penalized by this rule.
Style/readability. This is subjective, and includes things like consistent indentation, meaningful function and variable names, use of functions, and clarity of intent.
Note: teams should not be overly concerned with these tie-breaking rules. Ties are very unlikely (we have never seen one) and these rules are provided only for completeness. Also, these rules are used only by the regional chief judges to break ties for determining the regional winners (those that will advance to the finals). Local sites are free to use whatever criteria they wish to break ties at their site, although we recommend that local sites not break ties at all.