摘要：
A. Reachable Numbers A. Reachable Numbers Let's denote a function f(x)f(x) in such a way: we add 11 to xx, then, while there is at least one trailing 阅读全文
摘要：
B. Long Number B. Long Number You are given a long decimal number aa consisting of nn digits from 11 to 99. You also have a function ff that maps ever 阅读全文