#include "islands.h"
#include <bits/stdc++.h>
using namespace std;
const int M = 1000;
vector<int> nei[M],ans;
map<pair<int,int>,int> ind;
int vis[M], par[M];
void dfs(int u)
{
vis[u]=1;
if (ans.size()) return;
for (int i:nei[u])
if (!vis[i])
par[i]=u,dfs(i);
else if(vis[i]==1)
{
int v=u;
while (v)
ans.push_back(ind[{par[v],v}]),v=par[v];
reverse(ans.begin(),ans.end());
ans.push_back(ind[{u,i}]);
int m=ans.size();
for (int o=0;o<m;o++)
{
if (ans[o]==ind[{par[i],i}])
{
for (int j=o+1;j<m;j++)
ans.push_back(ans[j]+1);
for (int j=m-1;j>o;j--)
ans.push_back(ans[j]);
for (int j=m-1;j>o;j--)
ans.push_back(ans[j]+1);
for (int j=o;j>=0;j--)
ans.push_back(ans[j]);
break;
}
}
break;
}
vis[u]=2;
}
variant<bool, vector<int>> find_journey(int n, int m, vector<int> U, vector<int> V)
{
for (int i=0;i<m;i+=2)
nei[U[i]].push_back(V[i]),ind[{U[i],V[i]}]=i;
dfs(0);
if (ans.size()) return ans;
return false;
}
