[Algorithms] List of online judges/algorithmical contests
Here is a list of websites, which are sets of algorithmical tasks or online contests: http://www.topcoder.com http://www.spoj.pl http://icpcres.ecs.baylor.edu/onlinejudge/ http://acm.timus.ru http://acm.mipt.ru/judge http://www.uwp.edu/sws/usaco/ http://acm.sgu.ru/ http://projecteuler.net/