#include "islands.h"
#include <variant>
#include <algorithm>
#include <bitset>
#include <cstdint>
#include <cstring>
#include <iostream>
#include <limits.h>
#include <math.h>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
//#define int long long
#define loop(X, N) for(int X = 0; X < (N); X++)
#define all(V) V.begin(), V.end()
#define rall(V) V.rbegin(), V.rend()
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;
typedef vector<bool> vb;
typedef vector<vector<bool>> vvb;
typedef uint64_t u64;
typedef int64_t i64;
int n, m;
vvi adj1;//adj2;
vb vis;
vi depths;
int counter = 0;
vii inOut;
void dfs(int node, int d) {
if (vis[node]) {
return;
}
vis[node] = true;
depths[node] = d;
inOut[node].first = counter++;
for (int child : adj1[node]) {
dfs(node, d + 1);
}
inOut[node].second = counter++;
}
bool isAncestor(int a, int b) {
return inOut[a].first <= inOut[b].first && inOut[b].first <= inOut[a].second;
}
bool success = false;
// bool isPossible(int node) {
// if (vis[node]) {
// return {node, false};
// }
// vis[node] = true;
// int closestBack = node;
// int cycleCount = 0;
// for (int child : adj1[node]) {
// auto [res, pos] = isPossible(child);
// if (isAncestor(node, res)) {
// cycleCount++;
// }
// if (isAncestor(node, res) && depths[closestBack] < depths[res]) {
// closestBack = res;
// }
// }
// if (cycleCount >= 2) {
// success = true;
// }
// return {closestBack, };
// }
vvii adj;
std::variant<bool, std::vector<int>> find_journey(int N, int M, vi U, vi V) {
n = N;
m = M;
adj = vvii(n);
loop(i, m) {
adj[U[i]].push_back({V[i], i});
}
if (n == 2) {
if (adj[0].size() < 2 || adj[1].size() < 1) {
return false;
}
return vi{ adj[0][0].second, adj[1][0].second, adj[0][1].second, adj[0][0].second, adj[1][0].second, adj[0][1].second };
}
return false;
// vis = vb(n);
// depths = vi(n);
// counter = 0;
// inOut = vii(n);
// dfs(0, 0);
// vis = vb(n);
// marked = vi(n);
// success = false;
// isPossible(0);
// return success;
}
