#include "islands.h"
#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using vvi = vector<vi>;
int n, m;
vi x, y;
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;
bool is_cycle = (m / 2) > n - 1; // not a tree
if (is_cycle) return true;
return false;
}
