Articulation Point

#include<iostream>
#include<cstdio>
#include<cstring>
#include<vector>
using namespace std;

#define si(n) scanf("%d",&n)
#define MAX 10005

vector<int>graph[MAX];
bool vis[MAX],arti_point[MAX];
int time,disc[MAX],low[MAX];

void dfs(int now,int prev){
    vis[now]=true;
    disc[now]=low[now]=time++;
    int child=0;
    for(int i=0;i<graph[now].size();i++){
        int to=graph[now][i];
        if(to==prev)
            continue;
        if(vis[to])
            low[now]=min(low[now],disc[to]);
        else{
            dfs(to,now);
            low[now]=min(low[now],low[to]);
            if(low[to]>=disc[now] && prev != -1){
                //now is articulation point
                arti_point[now]=true;
            }
            child++;
        }
    }
    if(prev == -1 && child>1){
        //now is articulation point
        arti_point[now]=true;
    }
}

int main()
{
    int i,j,n,m;
    freopen("input.txt","r",stdin);
    si(n);si(m);
    for(i=0;i<m;i++){
        int u,v;
        si(u);si(v);
        graph[u].push_back(v);
        graph[v].push_back(u);
    }
    memset(arti_point,false,sizeof(arti_point));
    memset(vis,false,sizeof(vis));

    for(i=0;i<n;i++){
        if(!vis[i])
            dfs(i,-1);
    }
    int ans=0;
    for(i=0;i<=n;i++)
        if(arti_point[i])
            ans++,cout<<i<<' ';
    cout<<endl;
    cout<<ans<<endl;

    return 0;
}