During 2003~2007 I was an undergraduate computer science student. In this time for our course material and for programming passion I used to try and solve ACM problems from the well known University of Valladolid site. I solved arround 203+ ACM problems from this site. Today I found in my laptop still the accepted codes are saved. So I think I should share these code. May be these could be useful for someone.
http://thinkdiff.net/mixed/200-acm-problems-solution-source-code