Submission #1495271

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Source Code Expand

#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define o(a) cout << a << endl
#define int long long
#define fi first
#define se second
using namespace std;
typedef pair<int, int> P;

int n, m;
vector<int> G[100010];
bool f[100010];

signed main(){
    cin >> n >> m;
    rep(i, 0, m){
        int a, b;
        cin >> a >> b;
        a--; b--;
        G[a]. push_back(b);
        G[b]. push_back(a);
    }
    vector<int> path;
    path. push_back(0);
    f[0] = true;
    int now = 0;
    rep(i, 0, n - 1){
        bool g = true;
        rep(j, 0, G[now].size()){
            if(f[G[now][j]] == false){
                now = G[now][j];
                path. push_back(now);
                f[now] = true;
                g = false;
                break;
            }
        }
        if(g) break;
    }
    now = 0;
    reverse(all(path));
    rep(i, 0, n - 1){
        bool g = true;
        rep(j, 0, G[now].size()){
            if(f[G[now][j]] == false){
                now = G[now][j];
                path. push_back(now);
                f[now] = true;
                g = false;
                break;
            }
        }
        if(g) break;
    }
    cout << path.size() << endl;
    rep(i, 0, path.size()){
        cout << path[i] + 1;
        if(i != path.size() - 1) cout << " ";
    }
    cout << endl;
}

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