I was one of the problem setters and judges for this event as well as reviewers for some of the problems. I figured it would be better to share my alternate solutions for others to learn and see if others can come up with better solutions. Together, we can get better, faster :) Here is the problem set and the input/output.
PS: You may want to check out analysis for problem J below. STL<vector> is slow. Of course, probably the most interesting problem is problem H - Serial Numbers :) I spent > 5 hours to write the analysis that problem. Enjoy :D