HDU - 1213 How Many Tables

问题

Today is Ignatius' birthday. He invites a lot of friends. Now it's dinner time. Ignatius wants to know how many tables he needs at least. You have to notice that not all the friends know each other, and all the friends do not want to stay with strangers. 

One important rule for this problem is that if I tell you A knows B, and B knows C, that means A, B, C know each other, so they can stay in one table. 

For example: If I tell you A knows B, B knows C, and D knows E, so A, B, C can stay in one table, and D, E have to stay in the other one. So Ignatius needs 2 tables at least. 

InputThe input starts with an integer T(1<=T<=25) which indicate the number of test cases. Then T test cases follow. Each test case starts with two integers N and M(1<=N,M<=1000). N indicates the number of friends, the friends are marked from 1 to N. Then M lines follow. Each line consists of two integers A and B(A!=B), that means friend A and friend B know each other. There will be a blank line between two cases. 
OutputFor each test case, just output how many tables Ignatius needs at least. Do NOT print any blanks. 
Sample Input

2
5 3
1 2
2 3
4 5

5 1
2 5

Sample Output

2
4

问题的主要意思是

　　有 N 个人拼桌吃饭，只有认识的人才会坐在一桌上。如果每一桌都能坐足够多的人，问大意是有几个桌子。

　　其实就是一个裸的并查集的问题，直接根据题意输入，输出操作之后的集合个数即可。