#include "parks.h"
#include <bits/stdc++.h>
using namespace std;
#define forn(i,n) for(int i=0;i<n;++i)
#define pb push_back
#define all(x) x.begin(), x.end()
#define pi pair<int,int>
#define f first
#define s second
int construct_roads(vector<int> x, vector<int> y) {
int n=x.size();
vector<int> u,v,a,b;
map<pi,int> m;
forn(i,n) m[{x[i],y[i]}]=i;
vector<pi> z={{-2,0},{2,0},{0,-2},{0,2}};
forn(i,n) {
int f=x[i], s=y[i];
for(auto&x:z) {
if (m.count({f+x.f,s+x.s})) {
if (i<m[{f+x.f,s+x.s}]) {
u.pb(i), v.pb(m[{f+x.f,s+x.s}]);
}
}
}
}
if (u.size()!=n-1) return 0;
forn(i,n-1) {
int x1=x[u[i]], y1=y[u[i]];
int x2=x[v[i]], y2=y[v[i]];
if (x1==x2) {
if ((max(y1,y2)+x1)%4) {
a.pb(x1+1);
b.pb(max(y1,y2)-1);
} else {
a.pb(x1-1);
b.pb(max(y1,y2)-1);
}
} else {
if ((max(x1,x2)+y1)%4) {
a.pb(max(x1,x2)-1);
b.pb(y1-1);
} else {
a.pb(max(x1,x2)-1);
b.pb(y1+1);
}
}
}
build(u,v,a,b);
return 1;
}
