zoj-1789

题目链接：http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=1789

题意：查找与0有关的人 即为SARS 并查集

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
int father[30005];
int rank[30005] ;
int n,m;
void init()
{
for(int i = 0 ; i < n ;i ++ )
{
father[i] = i;
rank[i] = 1; //自身节点为1
}
}
int find(int x)
{
if(x != father[x]) return find(father[x]);
return father[x] ;
}
void Union(int x,int y)
{
int xx = find(x);
int yy = find(y);
if(xx == yy) return ;
father[xx] = yy;
rank[yy] += rank[xx] ; //记录共同祖先的有多少个成员
}
int main()
{
int a,b,k;
while(scanf("%d%d",&n,&m),n+m)
{
init();
for(int i = 0; i < m ; i++)
{
scanf("%d%d",&k,&a);
for(int j = 1 ; j < k ;j ++)
{
scanf("%d",&b);
Union(a,b);
a = b ;
}
}
printf("%d\n",rank[find(0)]);//查找0的祖先
}
}