“hiho” is a weekly series of contest we developed to help programmers improve their skills following some architecture. And for the beginning of this series, we present the "String". Dealing with strings is a very common problem when you go into the real world as a programmer. Although we usually use the standard methods to deal with them, these standard methods actually contain a lot of brilliant ideas inside them. So we think it's a good idea to hiho some typical string problems to all of you, as it will help hone your programming thinking.

"Trie!", the problem of this week, introduces a solution to "String Autocompletion". And many other kind of algorithms are derived from it to make today's search engines, e-dictionary and input method. So come and learn it with Hi and Ho!

After the end of this contest, we will publish the source code of little HO and all the participants that solved this problem. Wish you learn from each other and make improvement togather!