摘要：
Given a positive integer X, an X-factor chain of length m is a sequence of integers, 1 = X0, X1, X2, …, Xm = X satisfying Xi < Xi+1 and Xi | Xi+1 wher 阅读全文
摘要：
Mike is frantically scrambling to finish his thesis at the last minute. He needs to assemble all his research notes into vaguely coherent form in the 阅读全文