#include "islands.h"
#include <variant>
#include <vector>
using namespace std;
const int maxn = 1010;
int edge_index[maxn][maxn], deg[maxn];
std::variant<bool, std::vector<int>> find_journey(
int N, int M, std::vector<int> U, std::vector<int> V)
{
bool spec = true;
for (int i = 0; i < M; i += 2)
{
if (V[i] != U[i + 1] || U[i] != V[i + 1])
spec = false;
}
if (N == 2)
{
int cnt0 = 0, cnt1 = 0;
vector < int > idx0, idx1;
for (int i = 0; i < M; i ++)
{
if (U[i] == 0)
cnt0 ++, idx0.push_back(i);
else
cnt1 ++, idx1.push_back(i);
}
if (cnt0 >= 2 && cnt1 >= 1)
{
vector < int > path;
path.push_back(idx0[0]);
path.push_back(idx1[0]);
path.push_back(idx0[1]);
path.push_back(idx0[0]);
path.push_back(idx1[0]);
path.push_back(idx0[1]);
return path;
}
return false;
}
else
if (spec)
{
for (int i = 0; i < M; i ++)
{
if (U[i] == 0)
deg[0] ++;
}
if (deg[0] == 1)
return false;
return true;
}
else
{
for (int i = 0; i < M; i ++)
edge_index[U[i]][V[i]] = i;
vector < int > path;
path.push_back(edge_index[0][1]);
path.push_back(edge_index[1][0]);
path.push_back(edge_index[0][2]);
path.push_back(edge_index[2][0]);
path.push_back(edge_index[1][0]);
path.push_back(edge_index[0][1]);
path.push_back(edge_index[2][0]);
path.push_back(edge_index[0][2]);
return path;
}
}
