摘要：
Ilya is very fond of graphs, especially trees. During his last trip to the forest Ilya found a very interesting tree rooted at vertex 1. There is an i 阅读全文
摘要：
Mayor of Yusland just won the lottery and decided to spent money on something good for town. For example, repair all the roads in the town. Yusland co 阅读全文
摘要：
【问题描述】山山很喜欢旅行,他坐飞机的次数也非常非常多,所以他成为了空中司机航空公司的会员,并且有一张白金会员卡。山山规划了接下来一段时间的行程,他需要坐飞机 n 次,现在空中司机给了他 m 种优惠政策。对于第 i 种政策,山山可以花费 ci 元办理一张“Ti 日通飞证”,这样他就可以 在某个连续的 阅读全文
摘要：
An infinitely long railway has a train consisting of n cars, numbered from 1 to n (the numbers of all the cars are distinct) and positioned in arbitra 阅读全文
摘要：
Watchmen are in a danger and Doctor Manhattan together with his friend Daniel Dreiberg should warn them as soon as possible. There are n watchmen on a 阅读全文