Submission #1222173

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Source Code Expand

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <cassert>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>

using namespace std;

#define f first
#define s second
#define pb push_back
#define pp pop_back
#define mp make_pair
#define ll long long
#define ld long double
#define ull unsigned long long
#define PI pair < int, int > 

const int N = 1e5 + 123;
const int M = 123;
const ld Pi = acos(-1);
const ll Inf = 1e18;
const int inf = 1e9;
const int mod = 1000200013;
const int Sz = 501;

void add(int &a, int b) {
  a += b;
  if (a >= mod) a -= mod;
}
int mult(int a, int b) {
  return 1ll * a * b % mod;
}
int sum(int a, int b) {
  add(a, b);
  return a;
}

int n, m;
vector < int > g[N], l, r;
bool in[N];

int main() {
  #ifdef wws
    freopen("in", "r", stdin);
   // freopen("out", "w", stdout);
  #endif 
  ios_base::sync_with_stdio(0);
  cin >> n >> m;
  int s, t;
  for (int i = 1, u, v;i <= m;i++) {
    cin >> u >> v;
    g[u].pb(v);
    g[v].pb(u);
    s = u, t = v;
  }
  bool ch = 1;
  in[s] = in[t] = 1;
  l.pb(s);
  r.pb(t);
  while(ch) {
    ch = 0;
//    cout << s << " " << t << endl;
    for (auto x : g[s]) {
      if (!in[x]) {
        l.pb(x);
        s = x;
        ch = 1;
        break;
      }
    }
    in[s] = 1;
    for (auto x : g[t]) {
      if (!in[x]) {
        r.pb(x);
        t = x;
        ch = 1;
        break;
      }
    }
    in[t] = 1;
  }
  cout << (int)l.size() + r.size() << endl;
  for (int i = l.size() - 1;i >= 0;i--) cout << l[i] << " ";
  for (int i = 0;i < r.size();i++) cout << r[i] << " ";
  cout << endl;
  return 0;
}

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