POJ-1236-Network of Schools

#include<cstdio>
#include<cstring>
#include<iostream>
#include<stack>
using namespace std;
const int maxn=110;
const int maxm=maxn*maxn;
int e,head[maxn],nxt[maxm],pnt[maxm],from[maxm],dfn[maxn],low[maxn],sccno[maxn],scc_no,dfs_clock;
int n,cnt_in[maxn],cnt_out[maxn];
stack<int> s;
void AddEdge(int u,int v)
{
pnt[e]=v;from[e]=u;nxt[e]=head[u];head[u]=e++;
}
int Tarjan(int u)
{
dfn[u]=low[u]=++dfs_clock;
s.push(u);
for(int i=head[u];i!=-1;i=nxt[i])
{
if(!dfn[pnt[i]])
low[u]=min(low[u],Tarjan(pnt[i]));
else if(!sccno[pnt[i]])
low[u]=min(low[u],dfn[pnt[i]]);
}
if(low[u]==dfn[u])
{
scc_no++;
for(;;)
{
int x=s.top();s.pop();
sccno[x]=scc_no;
if(x==u)
break;
}
}
return low[u];
}
void solve()
{
memset(cnt_in,0,sizeof(cnt_in));
memset(cnt_out,0,sizeof(cnt_out));
memset(dfn,0,sizeof(dfn));
memset(sccno,0,sizeof(sccno));
for(int i=1;i<=n;i++)
if(!dfn[i])
Tarjan(i);
if(scc_no==1)
{
printf("1\n0\n");
return;
}
for(int i=0;i<e;i++)
if(sccno[from[i]]!=sccno[pnt[i]])
{
cnt_out[sccno[from[i]]]++;
cnt_in[sccno[pnt[i]]]++;
}
int cntin=0,cntout=0;
for(int i=1;i<=scc_no;i++)
{
if(!cnt_in[i])
cntin++;
if(!cnt_out[i])
cntout++;
}
printf("%d\n%d\n",cntin,max(cntin,cntout));
}
int main()
{
while(scanf("%d",&n)!=EOF)
{
e=scc_no=dfs_clock=0;
memset(head,-1,sizeof(head));
for(int i=1;i<=n;i++)
{
while(1)
{
int v;
scanf("%d",&v);
if(!v)
break;
AddEdge(i,v);
}
}
solve();
}
return 0;
}