摘要：描述 在美丽的玄武湖畔，鸡鸣寺边，鸡笼山前，有一块富饶而秀美的土地，人们唤作进香河。相传一日，一缕紫气从天而至，只一瞬间便消失在了进香河中。老人们说，这是玄武神灵将天书藏匿在此。 很多年后，人们终于在进香河地区发现了带有玄武密码的文字。更加神奇的是，这份带有玄武密码的文字，与玄武湖南岸台城的结构有微 阅读全文

摘要：You have nn lights, each with its own button, in a line. Pressing a light’s button will toggle that light’s state; if the light is on, it will turn of 阅读全文

摘要：You are given a rooted tree with n nodes. The nodes are numbered 1..n. The root is node 1, and m of the nodes are colored red, the rest are black. You 阅读全文

摘要：Given a registry of all houses in your state or province, you would like to know the minimum size of an axis-aligned square zone such that every house 阅读全文

摘要：Consider n initial strings of lower case letters, where no initial string is a prefix of any other initial string. Now, consider choosing k of the str 阅读全文