运用stl
代码 c++

#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
const double eps = 1e-6;
const int N=1e4+333;
const ll mod = 1e9+7;
int n,m,in[N*6],dis[N*6],cnt=1;
vector<int> g[N*10];

int main()
{

    cin>>n>>m;
    for (int i = 1;i <= m;i ++) {
        int num;cin>>num;
        set<int> s;
        while(num--) {
            int x;cin>>x;
            s.insert(x);
        }
        int var = n+i;
        for (int j=*s.begin();j<=*s.rbegin();j++) {
            if(s.count(j)==1) {
                g[var].push_back(j);in[j]++;
            }
            else {
                g[j].push_back(var);in[var]++;
            }
        }

    }
    queue<int> q;
    for (int i=1;i<=n+m;i++) {
        if(in[i]==0) q.push(i); 
        if(i<=n) dis[i]=1;
    }

    while (!q.empty()) {
        int node = q.front();
        q.pop();int w;
        if(node<=n)  w=0;
        else  w=1;

        for (int i=0;i<g[node].size();i++) {
            int u =g[node][i];
            dis[u]=max(dis[u],dis[node]+w);
            in[u]--;
            if(in[u]==0) q.push(u);

        }
    }
    int ans=1;
    for (int i=1;i<=n;i++)
    ans=max(ans,dis[i]);

    cout<<ans<<endl;

    return 0;
}