并查集简单题-pku1611

题目链接：http://poj.org/problem?id=1611

代码：

 

#include<stdio.h>

int father[30001];

int count[30001];

int i,m,n,first,a,b;

void setfather(int n) //初始化，将各自fahter设置为本身

{

	for(i=0;i<n;i++)

	{

		father[i]=i;

		count[i]=1;

	}

}

int findfather(int i)   

{

	if(i!=father[i])

		father[i]=findfather(father[i]);

	return father[i];

}

void Untion(int a,int b)  

{

	int m1=findfather(a);

	int m2=findfather(b);

	if(m1==m2)

		return;

    if(count[m1]>=count[m2])  //若不相等，则将值赋值给较大的

	{

		father[m2]=m1;

		count[m1]=count[m2]+count[m1];

	}

	else

	{

		father[m1]=m2;

		count[m2]=count[m1]+count[m2];

	}

}

int main()

{

	while(scanf("%d %d",&n,&m)!=EOF&&n>0)

	{

		if(n>=0&&n<=30000&&m>=0&&m<=500)

		{

			setfather(n);

			while(m>0)

			{

			scanf("%d %d",&a,&first);

			for(i=0;i<a-1;i++)

			{

				scanf("%d",&b);

				Untion(first,b);

			}

			m--;

			}

			printf("%d\n",count[findfather(0)]);

		}

	}



	return 0;

}