摘要：
A. Visiting a Friend A. Visiting a Friend Pig is visiting a friend. Pig's house is located at point 0, and his friend's house is located at point m on 阅读全文
摘要：
D. Shovel Sale There are n shovels in Polycarp's shop. The i-th shovel costs i burles, that is, the first shovel costs 1 burle, the second shovel cost 阅读全文