UVa 280 - Vertex

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>

using namespace std;

int maps[110][110];
int used[110];

void dfs(int s, int n)
{
for (int i = 1 ; i <= n ; ++ i)
if (!used[i] && maps[s][i]) {
used[i] = 1;
dfs(i, n);
}
}

int main()
{
int n,m,a,b,s;
while (~scanf("%d",&n) && n) {
memset(maps, 0, sizeof(maps));
while (~scanf("%d",&a) && a)
while (~scanf("%d",&b) && b)
maps[a][b] = 1;
scanf("%d",&m);
for (int i = 0 ; i < m ; ++ i) {
memset(used, 0, sizeof(used));
scanf("%d",&s);
dfs(s, n);
int count = n;
for (int j = 1 ; j <= n ; ++ j)
count -= used[j];
printf("%d",count);
for (int j = 1 ; j <= n ; ++ j)
if (!used[j])
printf(" %d",j);
printf("\n");
}
}

return 0;
}