#include "parks.h"
#include <bits/stdc++.h>
using namespace std;
constexpr int kMinX = 2;
constexpr int kMidX = 4;
constexpr int kMaxX = 6;
int construct_roads(std::vector<int> X, std::vector<int> Y) {
int N = X.size();
vector<map<int, int>> pos(kMaxX + 1);
for (int i = 0; i < N; ++i) {
pos[X[i]][Y[i]] = i;
}
vector<int> parent(N);
iota(parent.begin(), parent.end(), 0);
function<int(int)> find_root = [&] (int u) {
return parent[u] = u == parent[u] ? u : find_root(parent[u]);
};
for (int i = 0; i < N; ++i) {
if (pos[X[i]].count(Y[i] + 2)) {
parent[find_root(i)] = find_root(pos[X[i]][Y[i] + 2]);
}
if (X[i] < kMaxX && pos[X[i] + 2].count(Y[i])) {
parent[find_root(i)] = find_root(pos[X[i] + 2][Y[i]]);
}
}
for (int i = 0; i < N; ++i) {
if (find_root(i) != find_root(0)) {
return 0;
}
}
vector<int> U, V, A, B;
for (int x : {kMinX, kMaxX}) {
for (map<int, int>::iterator it = pos[x].begin();
it != pos[x].end();
++it) {
int y = it->first;
if (pos[x].count(y + 2)) {
U.push_back(pos[x][y]);
V.push_back(pos[x][y + 2]);
A.push_back(x == kMinX ? x - 1 : x + 1);
B.push_back(y + 1);
}
}
}
for (map<int, int>::iterator it = pos[kMidX].begin();
it != pos[kMidX].end();
++it) {
int x = kMidX;
int y = it->first;
if (pos[x].count(y + 2)) {
U.push_back(pos[x][y]);
V.push_back(pos[x][y + 2]);
B.push_back(y + 1);
if (y & 2) {
A.push_back(x + 1);
if (pos[x - 2].count(y)) {
U.push_back(pos[x][y]);
V.push_back(pos[x - 2][y]);
A.push_back(x - 1);
B.push_back(y + 1);
}
if (pos[x + 2].count(y)) {
if (pos[x + 2].count(y - 2) == 0 || pos[x].count(y - 2) == 0) {
U.push_back(pos[x][y]);
V.push_back(pos[x + 2][y]);
A.push_back(x + 1);
B.push_back(y - 1);
}
}
} else {
A.push_back(x - 1);
if (pos[x - 2].count(y)) {
if (pos[x - 2].count(y - 2) == 0 || pos[x].count(y - 2) == 0) {
U.push_back(pos[x][y]);
V.push_back(pos[x - 2][y]);
A.push_back(x - 1);
B.push_back(y - 1);
}
}
if (pos[x + 2].count(y)) {
U.push_back(pos[x][y]);
V.push_back(pos[x + 2][y]);
A.push_back(x + 1);
B.push_back(y + 1);
}
}
} else {
for (int d : {-1, 1}) {
if (pos[x + d * 2].count(y)) {
U.push_back(pos[x][y]);
V.push_back(pos[x + d * 2][y]);
A.push_back(x + d);
B.push_back(y + 1);
}
}
}
}
build(U, V, A, B);
return 1;
}
