rt

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=1005;
int n,m,s,rd[N],a[N],ans,top;
bool vis[N],gt[N],e[N][N];
int read()
{
    int m=0,n=1; 
	char ch;
	ch=getchar();
    while(ch<'0'||ch>'9')
	{  
	    if(ch=='-') 
		 n=-1;
	    ch=getchar();
	}
    while(ch>='0'&&ch<='9')
	{
	    m=m*10+ch-'0';
	    ch=getchar();
	}
    return m*n;
}
signed main()
{
//	freopen(".in","r",stdin);
//	freopen(".out","w",stdout);
	n=read();m=read();
	for(int i=1;i<=m;i++){
		for(int j=1;j<=n;j++){
			gt[j]=false;
			a[j]=0;
		}
		s=read();
		for(int j=1;j<=s;j++){
			a[j]=read();
			gt[a[j]]=true;
		}
		for(int j=1;j<=s;j++){
			for(int k=a[1];k<=a[s];k++){
				if(!gt[k]&&!e[a[j]][k]){
					e[a[j]][k]=true;
					rd[k]++;
				}
			}
		}
	}
	do{
		top=0;
		for(int i=1;i<=n;i++){
			if(!rd[i]&&!vis[i]){
				a[++top]=i;
				vis[i]=true;
			}
		}
		ans++;
		for(int i=1;i<=top;i++){
			for(int j=1;j<=n;j++){
				if(e[a[i]][j]){
					rd[j]--;
					e[a[i]][j]=false;
				} 
			}
		}
	}while(top>0);
	printf("%d",ans-1);
}

有没有大佬帮帮忙，求求了Orz