#include <bits/stdc++.h>
#define ll long long
#define str string
#define ins insert
#define ld long double
#define pb push_back
#define pf push_front
#define pof pop_front()
#define pob pop_back()
#define lb lower_bound
#define ub upper_bound
#define endl "\n"
#define fr first
#define sc second
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define sz size()
#define bc back()
//#define ar array
#define vll vector<ll>
using namespace std;/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;*/
template <class _T>
bool chmin(_T &x, const _T &y){
if(x>y){
x=y;
return true;
}
return false;
}
template <class _T>
bool chmax(_T &x, const _T &y){
bool flag=false;
if (x<y){
x=y;flag|=true;
}
return flag;
}
//#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>
void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
void start(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
//const ll inf=2e18+7;
const ll mod=1e9+7;
const ll N=2e6+7;
vector<vector<pair<ll,ll>>> t(N*4),ar(N);
vector<vll> g(N);
ll comp[N];
ll val[N];
void build(ll v,ll tl,ll tr){
if(tl==tr){
for(auto i : ar[tl])t[v].pb(i);
return;
}
ll tm=(tl+tr)/2;
build(v*2,tl,tm);
build(v*2+1,tm+1,tr);
for(auto i : t[v*2])t[v].pb(i);
for(auto i : t[v*2+1])t[v].pb(i);
}
vector<pair<ll,ll> > get(ll v,ll tl,ll tr,ll l,ll r){
if(tl>r || tr<l)return {};
if(l<=tl && tr<=r)return t[v];
ll tm=(tl+tr)/2;
vector<pair<ll,ll>> vv;
for(auto i : get(v*2,tl,tm,l,r))vv.pb(i);
for(auto i : get(v*2+1,tm+1,tr,l,r))vv.pb(i);
return vv;
}
void dfs(ll v,ll c){
comp[v]=c;
for(auto i : g[v]){
if(comp[i])continue;
dfs(i,c);
}
}
bool flag[N];
void solve(){
ll i;
ll n;
ll a,b;
cin>>n;
vector<vector<pair<ll,ll>>> cur(n*2+5);
vector<pair<ll,ll>> v(n+1);
v[0]={0,0};
for(i=1;i<=n;i++) cin>>v[i].fr>>v[i].sc;
ll mx=0;
sort(all(v));
for(i=1;i<=n;i++){
if(mx>=v[i].sc)flag[i]=true;
mx=max(mx,v[i].sc);
}
for(i=1;i<=n;i++){
if(flag[i])continue;
a=v[i].fr;
b=v[i].sc;
ar[b].pb({a,i});
cur[a].pb({b,i});
}
build(1,1,n*2);
for(i=1;i<=2*n;i++){
for(auto j : cur[i]){
vector<pair<ll,ll>> v=get(1,1,n*2,i,j.fr);
sort(all(v));
for(auto q : v){
if(q.fr>=i)break;
g[q.sc].pb(j.sc);
g[j.sc].pb(q.sc);
val[j.sc]=max(val[q.sc]+1,val[j.sc]);
}
if(val[j.sc]>1){
cout<<0<<endl;
return;
}
}
for(auto j : ar[i]){
for(auto to : g[j.sc]){
val[to]--;
}
}
}
ll c=0;
for(i=1;i<=n;i++){
if(comp[i]==0)dfs(i,++c);
}
ll x=1;
for(i=1;i<=c;i++){
x*=2;
x%=mod;
}
cout<<x<<endl;
}
signed main(){
start();
ll t=1;
//cin>>t;
while(t--) solve();
return 0;
}
/*
35
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11 12
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43 44
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59 60
61 62
63 64
65 66
67 68
69 70
*/
Compilation message
port_facility.cpp: In function 'void fre(std::string)':
port_facility.cpp:42:27: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
42 | void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
port_facility.cpp:42:64: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
42 | void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
80 ms |
282160 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
80 ms |
282160 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
80 ms |
282160 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
80 ms |
282160 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
