摘要：
Alice and Bob's game never ends. Today, they introduce a new game. In this game, both of them have N different rectangular cards respectively. Alice w 阅读全文
摘要：
You can perfectly predict the price of a certain stock for the next N days. You would like to profit on this knowledge, but only want to transact one 阅读全文
摘要：
As meticulous Gerald sets the table and caring Alexander sends the postcards, Sergey makes snowmen. Each showman should consist of three snowballs: a 阅读全文
摘要：
Farmer John went to cut some wood and left N (2 ≤ N ≤ 100,000) cows eating the grass, as usual. When he returned, he found to his horror that the clus 阅读全文
摘要：
Assume the coasting is an infinite straight line. Land is in one side of coasting, sea in the other. Each small island is a point locating in the sea 阅读全文
摘要：
You are given a rooted tree with n vertices. The vertices are numbered from 1 to n, the root is the vertex number 1. Each vertex has a color, let's de 阅读全文