#include <bits/stdc++.h>
#include "parks.h"
using namespace std;
int construct_roads(vector<int> xs, vector<int> ys) {
int n = xs.size();
map<pair<int, int>, int> points;
for (int i = 0; i < n; ++i)
points[make_pair(xs[i], ys[i])] = i;
vector<int> rep(n); int comps = n;
for (int i = 0; i < n; ++i)
rep[i] = i;
function<int (int)> find = [&rep, &find](int u) {
if (rep[u] == u) return u;
return rep[u] = find(rep[u]);
};
function<void (int, int)> une = [&rep, &comps, &find](int u, int v) {
u = find(u); v = find(v);
if (u == v) return;
rep[u] = v;
--comps;
};
vector<int> us, vs, as, bs;
for (int i = 0; i < n; ++i) {
int x = xs[i], y = ys[i];
if (points.find(make_pair(x + 2, y)) != points.end()) {
us.push_back(i);
vs.push_back(points[make_pair(x + 2, y)]);
une(us.back(), vs.back());
as.push_back(3);
bs.push_back(y + 1);
}
if (points.find(make_pair(x, y + 2)) != points.end()) {
us.push_back(i);
vs.push_back(points[make_pair(x, y + 2)]);
une(us.back(), vs.back());
if (x == 2) {
as.push_back(1);
bs.push_back(y + 1);
}
else {
as.push_back(5);
bs.push_back(y + 1);
}
}
}
if (comps > 1) return 0;
build(us, vs, as, bs);
return 1;
}
