YOONGI

The Accomodation of StudentsThere are a group of students. Some of them may know each other, while others don't. For example, A and B know each other, B and C know each other. But this may not imply...

Fire NetSuppose that we have a square city with straight streets. A map of a city is a square board with n rows and n columns, each representing a street or a piece of wall. A blockhouse is a small...

CoursesConsider a group of N students and P courses. Each student visits zero, one or more than one courses. Your task is to determine whether it is possible to form a committee of exactly P student...

棋盘游戏小希和Gardon在玩一个游戏：对一个N*M的棋盘，在格子里放尽量多的一些国际象棋里面的“车”，并且使得他们不能互相攻击，这当然很简单，但是Gardon限制了只有某些格子才可以放，小希还是很轻松的解决了这个问题（见下图）注意不能放车的地方不影响车的互相攻击。 所以现在Gardon想让小希来解决一个更难的问题，在保证尽量多的“车”的前提下，棋盘里有些格子是可以避开的，也就是说，不在这些...

过山车RPG girls今天和大家一起去游乐场玩，终于可以坐上梦寐以求的过山车了。可是，过山车的每一排只有两个座位，而且还有条不成文的规矩，就是每个女生必须找个个男生做partner和她同坐。但是，每个女孩都有各自的想法，举个例子把，Rabbit只愿意和XHD或PQK做partner，Grass只愿意和linle或LL做partner，PrincessSnow愿意和水域浪子或伪酷儿做partn...

Vertex Coverfrog has a graph withnnverticesv(1),v(2),…,v(n)v(1),v(2),…,v(n)andmmedges(v(a1),v(b1)),(v(a2),v(b2)),…,(v(am),v(bm))(v(a1),v(b1)),(v(a2),v(b2)),…,(v(am),v(bm)).She would like to...

NP-Hard ProblemRecently, Pari and Arya did some research about NP-Hard problems and they found theminimum vertex coverproblem very interesting.Suppose the graphGis given. SubsetAof its verti...