Hiho! is a serial contests we developed to help programmers improve their skills following some architecture. After the problems in "String" serial, we now focus on "Dynamic programming". One of the core idea of Dynamic programming is not to calculate what has been calculated, not to calculate what is no used, and Hi call this idea "Release Redundancy". But this kind of technique is learning required. So we collect some classic dynamic programming problem here, analysis the redundancy in it, summerize the its regularity. Hope it will help your programming thinking.

And this week, Hi and Ho will challenge the problem "State Compression Dynamic Programming" again. But this time, the state won't be a single array but a rectangle! At the same time, the problem is no longer the "Best" but the "Sum" of all solutions. What will Hi and Ho solve this? Don't wait and learn it with Hi and Ho!