这个复杂度不对吧？但是AC了

暴力连边跑拓扑，应该是 \frac{n^2m}4 吧

#include<bits/stdc++.h>
#define maxn 1001
using namespace std;
int n,m,indgr[maxn],level[maxn],ans=1,s[maxn],up[maxn],down[maxn],topup,topdown;
bool edge[maxn][maxn];queue<int>q;
signed main(){
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    cin>>n>>m;
    for(int i=1;i<=m;++i){
        int len;cin>>len;topup=topdown=0;
        for(int j=1;j<=len;++j)cin>>s[j];
        int res=s[1];
        for(int j=1;j<=len;++j){
            up[++topup]=s[j];
            if(s[j]-1>res)for(int k=res+1;k<s[j];++k)down[++topdown]=k;
            res=s[j];
        }
        for(int j=1;j<=topup;++j){
            for(int k=1;k<=topdown;++k){
                if(!edge[down[k]][up[j]])indgr[up[j]]++;
                edge[down[k]][up[j]]=1;
            }
        }
    }
    for(int i=1;i<=n;++i)level[i]=1;
    for(int i=1;i<=n;++i)if(indgr[i]==0)q.push(i);
    while(q.size()){
        int now=q.front();q.pop();
        for(int i=1;i<=n;++i){
            int v=edge[now][i];
            if(v)v=i;
            else continue;
            if(level[v]<=level[now])
                level[v]=level[now]+1;
            indgr[v]--;
            if(indgr[v]==0)q.push(v);
        }
    }
    for(int i=1;i<=n;++i)ans=max(ans,level[i]);
    cout<<ans;
    return 0;
}