Official sites Past SWERCs Problem archives Ecole Polytechnique Paris Click on a category above to see the links. Valladolid university Online superjudge :: [http://acm.uva.es/problemset/] Ural university :: [http://acm.timus.ru/en/] ACM Problem set archive :: [http://www.acm.inf.ethz.ch/ProblemSetArchive.html]