poj 1611 The Suspects

并查集 简单题

#include<cstdio>
#include<memory.h>
int par[1000];
int Find(int x)
{
    while(par[x] >= 0)
        x = par[x];
    return x;
}
void Merge(int x,int y)
{
    int a,b;
    int tmp;
    a = Find(x);
    b = Find(y);
    if(a != b)
    {
        tmp = par[a] + par[b];
        if(a < b) //0 shi gan ran suoyi xiaode youxian
        {
            par[b] = a;
            par[a] = tmp;
        }
        else
        {
            par[a] = b;
            par[b] = tmp;
        }
    }
}
int main()
{
    freopen("input.txt","r",stdin);
    int a,b,n,m,t;
    int cnt;
    while(scanf("%d%d",&n,&m) && n)//这里不能scanf("%d%d",&n,&m) && n && m) 因为m为0时同样可以
    {

        memset(par,-1,sizeof(par));
        while(m--)
        {
            scanf("%d",&t);
            scanf("%d",&a);
            t--;
            while(t--)
            {
                scanf("%d",&b);
                Merge(a,b);
            }
        }

        printf("%d
",-par[0]);
    }
}