hdoj 1213 How Many Tables

How Many Tables

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 15314    Accepted Submission(s): 7501

Problem Description

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.

 

Input

The 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.

 

Output

For 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

 

很明显的并查集...但是输出格式太坑，每个输出数据只需一个空格即可！PE2次才过...

#include<stdio.h>
#define max 1000+10
int set[max];
int find(int parent)
{
	int child=parent;
	int t;
	while(parent!=set[parent])
	parent=set[parent];
	while(child!=parent)
	{
		t=set[child];
		set[child]=parent;
		child=t;
	}
	return parent;
}
void merge(int x,int y)
{
	int fx=find(x);
	int fy=find(y);
	if(fx!=fy)
	set[fx]=fy;
}
int main()
{
	int n;
	int man;//总人数 
	int fman;//互相熟悉的组数 
	int i,x,y;
	int need;//需要的桌子数 
	scanf("%d",&n);
	while(n--)
	{
		scanf("%d%d",&man,&fman);
		for(i=1;i<=man;i++)
		set[i]=i;
		while(fman--)
		{
			scanf("%d%d",&x,&y);
			merge(x,y);
		}
		need=0;
		for(i=1;i<=man;i++)
		{
			if(set[i]==i)
			need++;
		}
		printf("%d\n",need);
	}
	return 0;
}