【codevs 2833】奇怪的梦境

#include<cstdio>
#include<iostream>
#include<queue>
#include<cstring>
using namespace std;
const int maxn=25000+5;
int tot=0,first[maxn],next[maxn],times[maxn];
queue<int>q;
int n,m,cnt=0;
struct edge
{
int f,t;
}es[maxn];
void build(int f,int t)
{
es[++tot]=(edge){f,t};
next[tot]=first[f];
first[f]=tot;
times[t]++;
}
int lala()
{
for(int i=1;i<=n;i++)
{
if(times[i]==0)
{
q.push(i);
times[i]--;
cnt++;
}
}
while(!q.empty())
{
int x=q.front();
q.pop();
for(int i=first[x];i!=-1;i=next[i])
{
int u=es[i].t;
times[u]--;
if(times[u]==0)
{
q.push(u);
times[u]--;
cnt++;
}

}
}
return cnt;
}
int main()
{
memset(first,-1,sizeof(first));
memset(times,0,sizeof(times));
scanf("%d%d",&n,&m);
int a,b;
for(int i=1;i<=m;i++)
{
scanf("%d%d",&a,&b);
build(a,b);
}
int ha=n-lala();
if(ha==0) cout<<"o(∩_∩)o"<<endl;
else cout<<"T_T"<<endl<<ha<<endl;
return 0;
}