#include <bits/stdc++.h>
#include "islands.h"
using namespace std;
vector<bool> vis;
vector<int> from;
vector<vector<int>> g;
bool found = 0;
int l, r;
void dfs(int u) {
vis[u] = 1;
for (auto v : g[u]) {
if (vis[v]) {
found = 1;
l = u; r = v;
return;
}
from[v] = u;
dfs(v);
if (found) return;
}
}
variant<bool, vector<int>> find_journey(int n, int m, vector<int> _u, vector<int> _v) {
g.resize(n);
vis.resize(n);
from.resize(n);
for (int i = 0; i < m; i++) {
int u = _u[i], v = _v[i];
g[u].push_back(v);
g[v].push_back(u);
}
for (int i = 0; i < n; i++) {
if (!vis[i]) {
from[i] = -1;
dfs(i);
}
}
if (!found) {
return false;
}
return {};
}
