KTH Challenge 2011, sponsored by Itello 

RulesIn short: you try to solve as many problems as possible from a set, without external help. What you may bring
What you may use
The contestThe problem set consists of a number of problems (usually 78). The problem set will be in English, and given to the participants when the contest begins. For each of these problems, you are to write a program in C, C++ or Java that reads from standard input (stdin) and writes to standard output (stdout), unless otherwise stated. After you have written a solution, you may submit it using the specified submission system. The contestant that solves the most problems correctly wins. If two contestants solve the same number of problems, the one with the lowest total time wins. If two top contestants end up with the same number of problems solved and the same total time, then the contestant with the lowest time on a single problem is ranked higher. If two contestants solve the same number of problems, with the same total time, and the same time on all problems, it is a draw. The time for a given problem is the time from the beginning of the contest to the time when the first correct solution was submitted, plus 20 minutes for each incorrect submission of that problem. The total time is the sum of the times for all solved problems, meaning you will not get extra time for a problem you never submit a correct solution to. If you feel that problem definition is ambiguous, you may submit a clarification request via the submission system. If the judges think there is no ambiguity, you will get a short answer stating this. Otherwise, the judges will write a clarification, that will be sent to all contestans. 
