Korn

input/code.cpp: In function 'int main()':
input/code.cpp:58:40: error: 'memset' was not declared in this scope
             memset(used, 0, sizeof used);
                                        ^

#include <iostream>
#include <vector>
using namespace std;
const int MN = 5e5+100;
vector<int> v[MN];
bool used[MN];
int f(int x, int ed, int lol) {
    used[x] = 1;
    for(int y: v[x]) {
        if(used[y] && y != ed && y != lol) {
            return 1;
        }
        if(!used[y]) {
            if(f(y, x, lol)) return 1;
        }
    }
    return 0;
}
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n,m;
    cin>>n>>m;
    for(int i = 0; i < m; ++i) {
        int a,b;
        cin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    int ma = 0;
    for(int i = 1; i <= n; ++i) {
        ma = max(ma, (int)v[i].size());
        if(v[i].size() % 2 != 0) {
            cout<<0<<endl;
            return 0;
        }
    }
    int maCnt = 0;
    for(int i = 1; i <= n; ++i) {
        if((int)v[i].size() == ma) ++maCnt;
    }
    if(maCnt > 2 && ma != 2) {
        cout<<0<<endl;
        return 0;
    }
    if(maCnt > 2 && ma == 2) {
        cout<<n<<endl;
        for(int i = 1; i <= n; ++i) {
            cout<<i<<' ';
        }
        cout<<endl;
        return 0;
    }
    //eli nyt maCnt <= 2
    vector<int> ans;
    for(int i = 1; i <= n; ++i) {
        if((int)v[i].size() == ma) {
            memset(used, 0, sizeof used);
            used[i] = 1;
            for(int x: v[i]) {
                if(!used[x] && f(x, i, i)) goto ohi;
            }
            ans.push_back(i);
            ohi:;
        }
    }
    cout<<ans.size()<<endl;
    for(int x: ans) {
        cout<<x<<' ';
    }
    cout<<'\n';
}