1166 Summit – PAT甲级真题

summit (峰会) is a meeting of heads of state or government. Arranging the rest areas for the summit is not a simple job. The ideal arrangement of one area is to invite those heads so that everyone is a direct friend of everyone.

Now given a set of tentative arrangements, your job is to tell the organizers whether or not each area is all set.

Input Specification:

Each input file contains one test case. For each case, the first line gives two positive integers N (≤ 200), the number of heads in the summit, and M, the number of friendship relations. Then M lines follow, each gives a pair of indices of the heads who are friends to each other. The heads are indexed from 1 to N.

Then there is another positive integer K (≤ 100), and K lines of tentative arrangement of rest areas follow, each first gives a positive number L (≤ N), then followed by a sequence of L distinct indices of the heads. All the numbers in a line are separated by a space.

Output Specification:

For each of the K areas, print in a line your advice in the following format:

  • if in this area everyone is a direct friend of everyone, and no friend is missing (that is, no one else is a direct friend of everyone in this area), print Area X is OK..
  • if in this area everyone is a direct friend of everyone, yet there are some other heads who may also be invited without breaking the ideal arrangement, print Area X may invite more people, such as H. where H is the smallest index of the head who may be invited.
  • if in this area the arrangement is not an ideal one, then print Area X needs help. so the host can provide some special service to help the heads get to know each other.

Here X is the index of an area, starting from 1 to K.

Sample Input:

8 10
5 6
7 8
6 4
3 6
4 5
2 3
8 2
2 7
5 3
3 4
6
4 5 4 3 6
3 2 8 7
2 2 3
1 1
2 4 6
3 3 2 1

Sample Output:

Area 1 is OK.
Area 2 is OK.
Area 3 is OK.
Area 4 is OK.
Area 5 may invite more people, such as 3.
Area 6 needs help.

题目大意:为峰会安排休息区,一个理想的安排是邀请这些领导人,每个人互相之间都是直接朋友。给定一套暂定的安排,判断每个区域是否都已准备就绪。输入格式:第一行给一个正整数N,表示峰会的首领数量,以及一个正整数M,表示友谊关系的数量。接下来是M行,每行给出一对互为朋友的领导人的编号。领导人的编号从1到N。然后给出另一个正整数K,接下来是K行暂定的休息区,每行给出一个正整数L,然后是一系列L个不同的领导人编号。一行中所有数字都用空格分隔。输出格式:对于K个休息区的每一个,请按以下格式将您的建议输出在一行中:如果在这个休息区每个人都互相是直接朋友,并且没有朋友漏掉(即没有其他人是这个休息区每个人的直接朋友),就输出Area X is OK.如果在这个休息区每个人都是每个人的直接朋友,但在不破坏理想安排的情况下,可能还会邀请一些其他领导人,就输出Area X may invite more people, such as H. H是可以被邀请的领导人的最小编号。如果该休息区的安排不理想,则输出Area X needs help. 这样主持人可以提供一些特别的服务帮助领导人们互相了解。
分析:二维数组A作为邻接矩阵存储两个人是否是好朋友,如果是u和v好朋友就将数组A[u][v] = A[v][u] = 1;集合temp存储待检查的序列号。先检查所有的人是不是互相都为好朋友,如果不是的话,直接输出needs help。然后,检查剩下的所有人中,是否有人是他们所有人的好朋友、但是没有被邀请的,如果没有,就输出is OK. 否则输出may invite more people, such as f. 其中f为可以被邀请的领导人的最小编号~

 

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