The Suspects poj 1611

The Suspects

Time Limit: 1000MS		Memory Limit: 20000K
Total Submissions: 34717		Accepted: 16846

Description

Severe acute respiratory syndrome (SARS), an atypical pneumonia of unknown aetiology, was recognized as a global threat in mid-March 2003. To minimize transmission to others, the best strategy is to separate the suspects from others. 
In the Not-Spreading-Your-Sickness University (NSYSU), there are many student groups. Students in the same group intercommunicate with each other frequently, and a student may join several groups. To prevent the possible transmissions of SARS, the NSYSU collects the member lists of all student groups, and makes the following rule in their standard operation procedure (SOP). 
Once a member in a group is a suspect, all members in the group are suspects. 
However, they find that it is not easy to identify all the suspects when a student is recognized as a suspect. Your job is to write a program which finds all the suspects.

Input

The input file contains several cases. Each test case begins with two integers n and m in a line, where n is the number of students, and m is the number of groups. You may assume that 0 < n <= 30000 and 0 <= m <= 500. Every student is numbered by a unique integer between 0 and n−1, and initially student 0 is recognized as a suspect in all the cases. This line is followed by m member lists of the groups, one line per group. Each line begins with an integer k by itself representing the number of members in the group. Following the number of members, there are k integers representing the students in this group. All the integers in a line are separated by at least one space. 
A case with n = 0 and m = 0 indicates the end of the input, and need not be processed.

Output

For each case, output the number of suspects in one line.

Sample Input

100 4
2 1 2
5 10 13 11 12 14
2 0 1
2 99 2
200 2
1 5
5 1 2 3 4 5
1 0
0 0

Sample Output

4
1
1

/*#include <iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
const int N=30010;
int pre[N],son[N];
int find(int x)
{
     return x==pre[x]?x:find(pre[x]);
}
void join(int x,int y)
{
      int xx=find(x);
      int yy=find(y);
      if(xx!=yy)
      {
           pre[yy]=xx;
           son[xx]+=son[yy];
      }
}
int main()
{
    int n,m,num;
    while(~scanf("%d%d",&n,&m)&&n+m)
    {
          for(int i=0;i<n;i++)
          {
              pre[i]=i;
              son[i]=1;
          }
          for(int i=1;i<=m;i++)
          {
               scanf("%d",&num);
               int *s=new int[num];
               for(int j=0;j<num;j++)
               {
                     scanf("%d",&s[j]);
                     if(j!=0)
                        join(s[j-1],s[j]);
               }
               delete s;
          }
          printf("%d\n",son[find(0)]);
    }
    return 0;
}*/
/*
#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
const int maxn=30005;
int father[maxn],son[maxn];
void init(int n)
{
       int i;
       for(i=0;i<n;i++)
       {
            father[i]=i;
            son[i]=1;
       }
}
int find(int x)
{
    int r=x,t;
    while(father[r]!=r) r=father[r];
    while(x!=r)
    {
          t=father[x];
          father[x]=r;
          x=t;
    }
    return x;
      //if(x!=father[x])
        //   father[x]=find(father[x]);
      //return father[x];
}
void unions(int x,int y)
{
       int xx=find(x);
       int yy=find(y);
       if(xx==yy)  return;
       if(son[xx]>=son[yy])
       {
           father[yy]=xx;
           son[xx]=son[xx]+son[yy];
       }
       else
       {
           father[xx]=yy;
           son[yy]=son[yy]+son[xx];
       }
}
int main()
{
       int n,m,k,first,next;
       int i,j;
       while(~scanf("%d%d",&n,&m))
       {
                if(!n&&!m)
                    break;
                init(n);
                for(i=0;i<m;i++)
                {
                    cin>>k>>first;
                    for(j=1;j<k;j++)
                    {
                        cin>>next;
                        unions(first,next);
                    }
                }
                cout<<son[father[0]]<<endl;
       }
}*/
/*
#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
const int maxn=30000+10;
int pa[maxn];//x的父亲节点;
int rank[maxn];//rank'[x]是x的高度的一个上界;
int num[maxn];////集合元素的个数;
void make_set(int x)
{//创建一个单元集;
    pa[x]=x;
    rank[x]=0;
    num[x]=1;
}
int find_set(int x)//带路径压缩的查找;
{//保存待查找的数;
    int r=x,t;
    //找到根节点;
    while(pa[r]!=r)
        r=pa[r];
    while(x!=r)
    {
        t=pa[x];
        pa[x]=r;
        x=t;
    }
    return x;
    //if(x!=pa[x])
    //pa[x]=find_set(pa[x]);
    // return pa[x];
}
//合并下，x,y所在的集合;
void union_set(int x,int y)
{
    int xx=find_set(x);
    int yy=find_set(y);
    if(xx==yy) return;
    if(rank[xx]>rank[yy])//让rank比较高的作为父结点
    {
        pa[yy]=xx;
        num[xx]+=num[yy];
    }
    else
    {
        pa[xx]=yy;
        //if(rank[xx]==rank[yy])
        //          rank[yy]++;
        num[yy]+=num[xx];
    }
}
int main()
{
    int n,m,i,j;
    while(~scanf("%d %d",&n,&m))
    {
        if(m==n&&n==0)   break;
        if(m==0)
        {
            cout<<"1\n";
            continue;
        }
        for(i=0; i<n; i++)
        {
            make_set(i);
        }
        int t,x;
        int y;
        for(i=0; i<m; i++)
        {
            scanf("%d",&t);
            scanf("%d",&x);
            for(j=1; j<t; j++)
            {
                scanf("%d",&y);
                union_set(x,y);
                x=y;
            }
        }
        x=find_set(0);/*找到0所在的树的树根*/
      /* cout<<num[x]<<endl;
    }
    return 0;
}*/
#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
const int maxn=30000+10;
int father[maxn];
int num[maxn];
int rank[maxn];
void set(int x)
{
       father[x]=x;
       num[x]=1;
       rank[x]=0;
}
int  find(int x)
{
       return x==father[x]?x:find(father[x]);
}
void join(int x,int y)
{
      int  xx=find(x);
      int yy=find(y);
      if(xx==yy) return;
      if(rank[xx]>rank[yy])
      {
             father[yy]=xx;
             num[xx]+=num[yy];
      }
      else
      {
           father[xx]=yy;
           num[yy]+=num[xx];
      }
}
int main()
{
        int n,m;
        while(~scanf("%d%d",&n,&m))
        {
               if(n==0&&m==0)
                break;
                for(int i=0;i<n;i++)
                    set(i);
               if(m==0)
               {
                     cout<<"1\n";continue;
               }
               int t,x,y;
                while(m--)
                {
                       cin>>t;
                       cin>>x;
                       for(int i=1;i<t;i++)
                       {
                            cin>>y;
                            join(x,y);
                            x=y;
                       }
                }
                x=find(0);
                printf("%d\n",num[x]);
        }
}