摘要:
Dicription You have a connected directed graph.Let $d(x)$ be the length of the shortest path from $1$ to $x$.Specially $d(1)=0$.A graph is good if the 阅读全文
摘要:
Discription Priests of the Quetzalcoatl cult want to build a tower to represent a power of their god. Tower is usually made of power-charged rocks. It 阅读全文