自环也考虑了

但一直wa三个点

都说我第二问做了emm

检查好久没看出来~

#include <bits/stdc++.h>
using namespace std;
const int inf=36500;
const int maxn=1e6+10;
int n,m,dp[maxn];
struct edge{
	int u,to,nxt;
}d[maxn]; int head[maxn],cnt=1;
void add(int u,int v){
	d[++cnt]=(edge){u,v,head[u]},head[u]=cnt;
}
int low[maxn],dfn[maxn],stac[maxn],vis[maxn],id,top,scc[maxn];
void tarjan(int u)
{
	low[u]=dfn[u]=++id,stac[++top]=u,vis[u]=1;
	for(int i=head[u];i;i=d[i].nxt )
	{
		int v=d[i].to;
		if( !dfn[v] )	tarjan(v),low[u]=min(low[u],low[v]);
		else if( vis[v] )	low[u]=min(low[u],dfn[v]);
	}
	if( dfn[u]==low[u] )
	{
		int temp,chu=inf;
		if( stac[top]==u )	chu=0;	
		while( temp=stac[top--] )
		{
			scc[temp]=u;
			vis[temp]=0;
			if( dp[temp]==0 ) dp[temp]=chu;//在环中,无限可能
			if( u==temp )	break; 
		}
	}
}
int in[maxn];
vector<int>vec[maxn];
void tuopu()
{
	queue<int>q;
	for(int i=1;i<=n+1;i++)
		if( i==scc[i]&&!in[i] )	q.push( scc[i] );
	dp[ scc[n+1] ]=1;
	while( !q.empty() )
	{
		int u=q.front(); q.pop();
		for(int i=0;i<vec[u].size();i++)
		{
			int v=vec[u][i];
			if( --in[v]==0 )	q.push( v );
			dp[v]+=dp[u];
			if( dp[v]>inf )	dp[v]=inf;
		}
	} 
}
int main()
{
	ios::sync_with_stdio(false);
	cin >> n >> m;
	for(int i=1;i<=m;i++)
	{
		int l,r; cin >> l >> r;
		add(r,l);
		if( l==r )	dp[l]=inf;
	}
	for(int i=1;i<=n+1;i++)
		if( !dfn[i] )	tarjan(i);
	for(int i=2;i<=cnt;i++)
	{
		int u=d[i].u,v=d[i].to;
		if( scc[u]==scc[v] )	continue;
		vec[ scc[u] ].push_back( scc[v] );//建立反向边
		in[ scc[v] ]++; 
	}
	tuopu();
	int maxx=0,shu=0;
	for(int i=1;i<=n+1;i++)
	{
		if( dp[i]>maxx )	maxx=dp[i],shu=1;
		else if( dp[i]==maxx )	shu++;
	}
	if( dp[scc[n+1]]==maxx )	shu--;
	if( maxx==inf )	cout << "zawsze\n";
	else	cout << maxx << '\n';
	cout << shu << endl;
	for(int i=1;i<=n;i++)
		if( dp[scc[i]]==maxx )	cout << i << " ";
}