Sites Like www.ProjectEuler.net

greetings /prog/
i'm about to join a small programming competition and i'm looking for some projecteuler type of websites where there are various math/programming challenges (so far i've managed to solve 32 problems).
if possible, there is also a way to check if my answer is correct on that site (because some sites only provide questions).

For the ICPC you can't beat http://acmicpc-live-archive.uva.es/nuevoportal/

As far as relaxing problems go SPOJ (http://www.spoj.pl/) and Project Euler are the kind of thing you might do on a Saturday night with a cup of soup.

Project Euler I find to be far too easy, and additionally the format of the problems is rather different than real contests and will get you into bad habits.

Once you are extremely competent you can try your hand at TopCoder, and perhaps even get paid to solve problems.

>>1
Try /prog/'s Weekly Challenge

>>3
I haven't seen an official one lately

At least not ones that are answerable by Xarn using Allegro to write a game

programmingpraxis?