#include "islands.h"
#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using vvi = vector<vi>;
int n, m;
vi x, y;
vvi adj;
variant<bool, vi> find_journey(int N, int M, vi U, vi V) {
n = N; m = M;
x = U; y = V;
map<pair<int, int>, int> edges;
for (int i = 0; i < m; i++) {
edges[{x[i], y[i]}]++;
}
bool is21 = false;
for (int i = 0; i < n; i++) {
for (int j = i+1; j < n; j++) {
if (edges[{i, j}] >= 2 && edges[{j, i}] >= 1) is21 = true;
}
}
if (is21) return true;
adj.assign(n, vi());
for (int i = 0; i < m; i+=2) {
adj[x[i]].push_back(y[i]);
}
vector<bool> seen(n, false);
queue<int> q; q.push(0);
while (!q.empty()) {
int cur = q.front();
q.pop();
seen[cur] = true;
for (auto &v : adj[cur]) {
if (seen[v]) return true;
q.push(v);
}
}
return false;
}
