단절점

#include <iostream>
#include <vector>
#define MAXX 10001
using namespace std;
 
int v, e;
bool ok[MAXX];
int order[MAXX];
vector<int> edge[MAXX];
int low[MAXX];
 
int z = 1;
int root = 1;
//시작 정점 
 
int dfs(int node) {
    low[node] = order[node];
 
    int child = 0;
    for (auto i : edge[node]) {
        if (order[i]) {
            //이미 방문한 노드 
            low[node] = min(low[node], order[i]);
        }
        else {
            order[i] = z++;
 
            int ret = dfs(i); 
            
            child++;
 
            low[node] = min(ret, low[node]);
 
            if (root != node && ret >= order[node]) {
                
                ok[node] = true;
            }
 
            if (root == node) {
                if (child >= 2) {
                    
                    ok[node] = true;
                }
 
            }
        }
    }
    return low[node];
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    
    int v, e;
    cin >> v >> e;
 
    for (int i = 0; i < e; i++) {
        int a, b;
        cin >> a >> b;
 
        edge[a].push_back(b);
        edge[b].push_back(a);
    }
 
    for (int i = 1; i <= v; i++) {
        if (!order[i]) {
            order[i] = z++; //방문 순서 기록 
            root = i;
            dfs(i);
            
        }
    }
    
    int ans = 0;
    vector<int> res;
    for (int i = 1; i <= v; i++) {
        if (ok[i]) {
            ans++;
            res.push_back(i);
        }
    }
    
    cout << ans << '\n';
    for (int i = 0; i < res.size(); i++) cout << res[i] << ' ';
    cout << '\n';
    return 0;
}