代码
#include<bits/stdc++.h>
using namespace std;
int main()
{int n,e,i,j,x,y;cin>>n >> e;vector<vector<int>> adj(n+1);for(i=0;i<e;++i){cin>>x>>y;adj[x].push_back(y);}for(i=1;i<=n;++i)sort(adj[i].begin(),adj[i].end());for(i=1;i<=n;++i){if(!adj[i].empty()){cout<<i<<endl;for(int j:adj[i])cout<<j<<" ";cout<<endl;}}return 0;
}
