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.

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.

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题意：

1

1

给出人数n和人数里的人群数m，同个群的人属于一个集合。求与编号0的人同个集合的人数（包括0本身)

代码入下：

#include<stdio.h>

#define maxn 30000

int father[maxn];

void setFather(int n)

{

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

{

father[i] = -1;

}

}

int find(int a)

{

if (father[a] < 0)

{

return a;

}

return father[a] = find(father[a]);

}

void Union(int a, int b)

{

a = find(a), b = find(b);

if (a != b)

{

if (father[a] < father[b])

{

father[a] += father[b];

father[b] = a;

}

else

{

father[b] += father[a];

father[a] = b;

}

}

}

int main()

{

int i, j, n, m, a, b, v, t;

while (1)

{

scanf("%d%d", &n, &m);

if (n == 0 && m == 0)

{

break;

}

setFather(n);

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

{

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

for (j = 1; j < v; j++)

{

scanf("%d", &b);

Union(a, b);

}

}

printf("%d\n", father[find(0)] * (-1));

}

return 0;

}

#define maxn 30000

int father[maxn];

void setFather(int n)

{

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

{

father[i] = -1;

}

}

int find(int a)

{

if (father[a] < 0)

{

return a;

}

return father[a] = find(father[a]);

}

void Union(int a, int b)

{

a = find(a), b = find(b);

if (a != b)

{

if (father[a] < father[b])

{

father[a] += father[b];

father[b] = a;

}

else

{

father[b] += father[a];

father[a] = b;

}

}

}

int main()

{

int i, j, n, m, a, b, v, t;

while (1)

{

scanf("%d%d", &n, &m);

if (n == 0 && m == 0)

{

break;

}

setFather(n);

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

{

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

for (j = 1; j < v; j++)

{

scanf("%d", &b);

Union(a, b);

}

}

printf("%d\n", father[find(0)] * (-1));

}

return 0;

}

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