UVA 208(p214)----Firetruck

#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;
int g[100][100],v[100],en,n,a[100],sum,m[100][100];
void floyd()
{
for(int k=1; k<=n; k++)
for(int i=1; i<=n; i++)
for(int j=1; j<=n; j++)
g[i][j]=g[i][j]||(g[i][k]&&g[k][j]);
}
void solve(int u,int num)
{
if(u==en)
{
sum++;
for(int i=0; i<num-1; i++)
printf("%d ",a[i]);
printf("%d\n",a[num-1]);
return;
}
else
for(int i=1; i<=n; i++)
{
if(!v[i]&&g[i][en]&&m[u][i])
{
v[i]=true;
a[num]=i;
solve(i,num+1);
a[num]=0;
v[i]=false;
}
}
}
int main()
{
// freopen("out.out","w",stdout);
int cas=0,x,y;
while(scanf("%d",&en)!=EOF)
{
sum=0;
cas++;
n=0;
memset(g,0,sizeof(g));
memset(v,0,sizeof(v));
memset(a,0,sizeof(a));
memset(m,0,sizeof(m));
v[1]=true;
a[0]=1;
while(scanf("%d%d",&x,&y)==2&&x)
{
// cout<<x<<" flj "<<y<<endl;
g[x][y]=true;
g[y][x]=true;
m[x][y]=true;
m[y][x]=true;
n=max(max(n,x),y);
}
// cout<<n<<endl;
floyd();
printf("CASE %d:\n",cas);
solve(1,1);
printf("There are %d routes from the firestation to streetcorner %d.\n",sum,en);
}
return 0;
}

题目地址：https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=4&page=show_problem&problem=144