tarjan+二分 30分 求改错

#define N 500005
#include<bits/stdc++.h>
using namespace std;

struct node{
	int to,next;
}e[N];

int n,m,cnt=0,head[N],du[N];
int dfn[N],low[N],vis[N],now; 
vector<int> g[100005];
stack<int> st;

inline void add(int a,int b){
//	printf("%d -> %d\n",a,b);
	e[++cnt].to=b;
	e[cnt].next=head[a];
	head[a]=cnt;
}

int tarjan(int u){
	dfn[u]=++now;
	low[u]=dfn[u];
	st.push(u); vis[u]=1;
	for(int i=head[u];i;i=e[i].next){
		int v=e[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]){
//		printf("new loop:\n");
		int sum=0,x;
		do{
			x=st.top(); st.pop(); sum++;
//			printf("has %d\n",x);
		}while(x!=u);
		return sum==1;
	}
	return 1;
}

int check(int x){
	//printf("#check %d\n",x);
	memset(head,0,sizeof(head));
	memset(dfn,0,sizeof(dfn));
	memset(low,0,sizeof(low));
	memset(vis,0,sizeof(vis));
	cnt=0; now=0;
	while(!st.empty()) st.pop();
	int a,b;
	for(int i=1;i<=x;i++){
		a=0;
		for(int j=0;j<(int)g[i].size();j++){
			b=g[i][j];
			if(a) add(a,b);
			a=b;
		}
	}
	for(int i=1;i<=n;i++){
		if(!dfn[i]){
			if(!tarjan(i)) return 0;
		}
	}
	return 1;
}

void show(int x){
	priority_queue<int,vector<int>,greater<int> > q;
	memset(head,0,sizeof(head));
	int a,b; cnt=0;
	for(int i=1;i<=x;i++){
		a=0;
		for(int j=0;j<(int)g[i].size();j++){
			b=g[i][j];
			if(a) add(a,b),du[b]++;
			a=b;
		}
	}
	for(int i=1;i<=n;i++){
		if(du[i]==0) q.push(i);
	}
	while(!q.empty()){
		int u=q.top(); q.pop();
		for(int i=head[u];i;i=e[i].next){
			int v=e[i].to;
			du[v]--;
			if(du[v]==0) q.push(v);
		}
		printf("%d ",u);
	}
}

int main(){
//	freopen("testdata.in","r",stdin);
	int x,k;
	scanf("%d%d",&n,&m);
	for(int i=1;i<=m;i++){
		scanf("%d",&k);
		for(int j=1;j<=k;j++){
			scanf("%d",&x);
			g[i].push_back(x);
		}
	}
	int l=1,r=m;
	while(l<r){
		int mid=(l+r)>>1;
		if(check(mid)) l=mid+1;
		else r=mid-1;
	}
	show(l-1);
	return 0;
}