I began to try to solve some DP problems, too.
And I got AC some problems.
Problems that I was able to get the correct answer easily are follows.
I think 103 is the most simple DP problem.
And 10069 is same as above.
But to solve this prolme needs BigNumber. You should use your library for BigNumber.
If you use matrix for 10069, you will get (or maybe not) MemoryLimitExceed, so you have to use array.
And the problem 10405 is not easy to solve for me.
But I got understand LCS, problem became easy. This problem is a simple LCS problem.
If I can find other easy DP problems, I will post replay.
I hope you can understand my poor English.