摘要：
题目描述 CC C国有n n n个大城市和m mm 条道路，每条道路连接这 nnn个城市中的某两个城市。任意两个城市之间最多只有一条道路直接相连。这 mmm 条道路中有一部分为单向通行的道路，一部分为双向通行的道路，双向通行的道路在统计条数时也计为 11 1条。 CC C国幅员辽阔，各地的资源分布情 阅读全文
摘要：
Bessie is out in the field and wants to get back to the barn to get as much sleep as possible before Farmer John wakes her for the morning milking. Be 阅读全文
摘要：
Farmer John wants to set up a telephone line at his farm. Unfortunately, the phone company is uncooperative, so he needs to pay for some of the cables 阅读全文