題目鏈接:http://poj.org/problem?id=1611
並查集簡單應用
#include <iostream>
using namespace std;
int father[30000],rank[30000];
void Make(int n)
{
int i;
for(i = 0;i < n;++i)
{
father[i] = i;
rank[i] = 1;
}
}
int Find(int x)
{
if(x != father[x])
father[x] = Find(father[x]);
return father[x];
}
void Union(int x,int y)
{
x = Find(x);
y = Find(y);
if(x == y) return;
if(rank[x] > rank[y])
{
father[y] = x;
rank[x] += rank[y];
}
else
{
father[x] = y;
rank[y] += rank[x];
}
}
int main(int argc, char** argv)
{
freopen("in.txt","r",stdin);
int n,m,k,cur;
while(scanf("%d%d",&n,&m) != EOF)
{
if(n == 0 && m == 0)
break;
Make(n);
int i,j,next;
for(i = 0;i < m;++i)
{
scanf("%d%d",&k,&cur);
for(j = 1;j < k;++j)
{
scanf("%d",&next);
Union(cur,next);
}
}
printf("%d\n",rank[Find(0)]);
}
return 0;
}