摘要：
Gappu has a very busy weekend ahead of him. Because, next weekend is Halloween, and he is planning to attend as many parties as he can. Since it's Hal 阅读全文
摘要：
Description The multiplication puzzle is played with a row of cards, each containing a single positive integer. During the move player takes one card 阅读全文
摘要：
Description We give the following inductive definition of a “regular brackets” sequence: the empty sequence is a regular brackets sequence, if s is a 阅读全文