#include "worldmap.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
vector<int> res;
vector<vector<int>> adj;
unordered_map<int,unordered_map<int,bool>> V;
void dfs(int cur, int parent = -1) {
res.push_back(cur+1);
for (auto x : adj[cur]) {
if(!V[cur][x]) {
V[cur][x] = V[x][cur] = true;
dfs(x);
res.push_back(cur+1);
}
}
}
std::vector<std::vector<int>> create_map(int N, int M, std::vector<int> A, std::vector<int> B) {
adj.clear();
V.clear();
res.clear();
adj.resize(N);
std::vector<std::vector<int>> ans;
for(int i=0;i<M;i++){
adj[A[i]-1].push_back(B[i]-1);
adj[B[i]-1].push_back(A[i]-1);
}
dfs(0);
for(int i=0;i<res.size();i++){
ans.push_back(res);
}
return ans;
}
