Hiho! is a serial contests we developed to help programmers improve their skills following some architecture. Tree, as a data structure, its most significant feature is that it can be divide in to several problem simply by its natural form, which it's similar to what we have told in "Dynamic Programming".

And this week, we will combine two problems "Tree" and "Dynamic programming" together, and introduce such kind of problem to you. And soon you will notice this was much likely to the problems we have told before.