I was reading "Using Tries" on topcoder and so tried to solve MORSE I think it requires Trie and DP. I have implemented a trie but I have not figured out the DP for this case. Can someone please explain me the DP approach ? Thanks.

Hello, I have been doing competitive programming for almost 2 years and I have decided to participate in ACM ICPC this year. Since there are so many questions on so many online judges, I do not have much time to solve questions randomly. I want to systematically prepare for ICPC, practicing every topic and each type of questions in that topic. How do I do that? How should I select the questions so as to cover maximum variety and techniques? Where do I study advanced topics like Heavy-light decomoposition, DP with broken profiles, etc? Any help would be highly appreciated. Thanks.