#include<bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define pb push_back
#define sz(x) (int)(x.size())
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define vi vector<int>
#define vp vector<pii>
#define vvi vector<vi>
#define ykh mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count())
#define __lg(x) 63-__builtin_clzll(x)
#define pow2(x) (1LL<<x)
void __print(int x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef local
void setio(){freopen("/Users/iantsai/Library/Mobile Documents/com~apple~CloudDocs/cpp/Empty.md","r",stdin);}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
void setio(){}
#define debug(x...)
#endif
void setIO(string s) {
freopen((s + ".in").c_str(), "r", stdin);
freopen((s + ".out").c_str(), "w", stdout);
}
struct line{
int a,b;
int operator()(const int x)const{
return a*x+b;
}
};
bool check(line l1,line l2,line l3){
return (l3.b-l2.b)*(l1.a-l2.a)<=(l2.b-l1.b)*(l2.a-l3.a);
}
const int mxn=1e6+5;
const int mod=1e9+7;
vector<int>adj[mxn];
int col[mxn];
int ans;
void dfs(int v,int pa){
for(auto u:adj[v]){
if(u==pa){
continue;
}
if(col[u]){
if(col[u]+col[v]!=3){
ans=0;
return;
}
}
else{
col[u]=3-col[v];
dfs(u,v);
}
}
}
signed main(){
setio();
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
int n;
cin>>n;
vector<pii>v;
ans=1;
v.pb({0,0});
vector<int>nxt(n+1);
vector<int>in[2*n+1];
for(int i=1;i<=n;i++){
int a,b;
cin>>a>>b;
v.pb({a,b});
in[a].pb(i);
}
set<pii>st;
for(int i=1;i<=2*n;i++){
for(auto id:in[i]){
while(sz(st) and st.begin()->F<v[id].F){
int x=st.begin()->S;
st.erase(st.begin());
st.insert({v[nxt[x]].S,nxt[x]});
}
auto cur=st.insert({v[id].S,id}).F;
vector<pii>del;
while(cur!=st.begin()){
cur=prev(cur);
del.pb(*cur);
}
for(auto p:del){
adj[p.S].pb(id);
adj[id].pb(p.S);
}
for(auto p:del){
if(p!=del.back())st.erase(p);
}
for(int j=1;j<sz(del);j++){
nxt[del[j].S]=del[j-1].S;
}
}
}
for(int i=1;i<=n;i++){
if(!col[i]){
col[i]=1;
dfs(i,i);
ans=ans*2%mod;
}
}
cout<<ans<<'\n';
}
/*
input:
*/
Compilation message
port_facility.cpp: In function 'void setIO(std::string)':
port_facility.cpp:42:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
42 | freopen((s + ".in").c_str(), "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
port_facility.cpp:43:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
43 | freopen((s + ".out").c_str(), "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
6016 ms |
25436 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
6016 ms |
25436 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
6016 ms |
25436 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
6016 ms |
25436 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
