#include "parks.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ii pair<ll,ll>
#define fi first
#define se second
#define puf push_front
#define pof pop_front
#define pub push_back
#define pob pop_back
#define lb lower_bound
#define ub upper_bound
#define rep(x,s,e) for (auto x=s-(s>e);x!=e-(s>e);s<e?x++:x--)
#define all(x) (x).begin(),(x).end()
#define sz(x) (int) (x).size()
struct UFDS{
int p[200005];
UFDS(){
rep(x,0,200005) p[x]=x;
}
int parent(int i){
if (p[i]==i) return i;
else return p[i]=parent(p[i]);
}
void unions(int i,int j){
i=parent(i),j=parent(j);
p[i]=j;
}
} ufds;
int n;
ii arr[200005];
//return values
vector<int> id1,id2;
vector<int> bx,by;
map<ii,int> id;
int construct_roads(std::vector<int> X, std::vector<int> Y) {
n=sz(X);
rep(x,0,n) arr[x]=ii(X[x],Y[x]);
rep(x,0,n) id[arr[x]]=x;
rep(x,0,n){
int i,j;
tie(i,j)=arr[x];
if (id.count(ii(i,j+2))){ //vertical
int temp=id[ii(i,j+2)];
ufds.unions(x,temp);
//cout<<"ver: "<<x<<" "<<temp<<endl;
if ((i+j)%4==0){ //left
id1.pub(x);
id2.pub(temp);
bx.pub(i-1);
by.pub(j+1);
}
else{
//right if possible
if (!id.count(ii(i+2,j)) || !id.count(ii(i+2,j+2))){
id1.pub(x);
id2.pub(temp);
bx.pub(i+1);
by.pub(j+1);
}
}
}
if (id.count(ii(i+2,j))){ //horizontal
int temp=id[ii(i+2,j)];
ufds.unions(x,temp);
//cout<<"hor: "<<x<<" "<<temp<<endl;
if (j%4==0){
if (i%4==0){ //up
id1.pub(x);
id2.pub(temp);
bx.pub(i+1);
by.pub(j+1);
}
else{ //down
id1.pub(x);
id2.pub(temp);
bx.pub(i+1);
by.pub(j-1);
}
}
else{
if (i%4==0){ //down if possible
if (!id.count(ii(i,j-2)) || !id.count(ii(i+2,j-2))){
id1.pub(x);
id2.pub(temp);
bx.pub(i+1);
by.pub(j-1);
}
}
else{ //up if possible
if (!id.count(ii(i,j+2)) || !id.count(ii(i+2,j+2))){
id1.pub(x);
id2.pub(temp);
bx.pub(i+1);
by.pub(j+1);
}
}
}
}
}
rep(x,0,n) if (ufds.parent(0)!=ufds.parent(x)) return 0;
build(id1,id2,bx,by);
return 1;
}
