#include <bits/stdc++.h>
#include "parks.h"
using namespace std;
int construct_roads(std::vector<int> x, std::vector<int> y) {
if (x.size() == 1) {
build({}, {}, {}, {});
return 1;
}
map<pair<int, int>, int> byc;
int n = x.size();
for (int i = 0; i < n; i++) {
byc[{x[i], y[i]}] = i;
}
vector<int> u, v, a, b;
vector<vector<int>> g(n);
auto add = [&](int i, int j) {
if (i < j) {
g[i].push_back(j);
g[j].push_back(i);
u.push_back(i);
v.push_back(j);
if (x[i] != x[j]) {
a.push_back((x[i] + x[j]) / 2);
b.push_back(y[i] + 1);
} else {
b.push_back((y[i] + y[j]) / 2);
if (x[i] == 2) {
a.push_back(1);
} else {
a.push_back(5);
}
}
}
};
for (int i = 0; i < n; i++) {
{
pair<int, int> pp = {x[i], y[i]};
pp.first += 2;
if (byc.count(pp)) {
add(i, byc[pp]);
}
}
{
pair<int, int> pp = {x[i], y[i]};
pp.second += 2;
if (byc.count(pp)) {
add(i, byc[pp]);
}
}
{
pair<int, int> pp = {x[i], y[i]};
pp.first -= 2;
if (byc.count(pp)) {
add(i, byc[pp]);
}
}
{
pair<int, int> pp = {x[i], y[i]};
pp.second -= 2;
if (byc.count(pp)) {
add(i, byc[pp]);
}
}
}
vector<int> used(n);
function<void(int)> dfs;
dfs = [&](int v) {
used[v] = 1;
for (int u : g[v]) {
if (!used[u]) {
dfs(u);
}
}
};
dfs(0);
if (*min_element(used.begin(), used.end()) == 0) {
return 0;
}
build(u, v, a, b);
return 1;
}
