Hiho! is a serial contests we developed to help programmers improve their skills following some architecture. Since the difficulty of "Dynamic Programming" serial came to such a level, we think it'd be better to put it away for a while. And we'd like to be more "Breath-first" rather than "Depth-first". So here's the deal, the serial "Tree" of Hiho! will be start!

Tree, as a data struct, 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 talk about a very interesting problem - how to restore the struct of tree by the result of its pre-order and in-order traversal? And we think it's a good problem to start study abount "Tree"! Hope you'll learn from it!