Submission #427169

#	Time	Username	Problem	Language	Result	Execution time	Memory
427169		jamezzz	Port Facility (JOI17_port_facility)	C++17	10 / 100	27 ms	11580 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
 
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb emplace_back
#define sz(x) (int)x.size()
#define all(x) x.begin(),x.end()
typedef pair<int,int> ii;
typedef long long ll;
 
#define mod 1000000007
 
struct node{
	int s,e,m;
	ii v;
	node *l,*r;
	node(int _s,int _e){
		s=_s;e=_e;m=(s+e)/2;v=ii(-1,-1);
		if(s!=e)l=new node(s,m),r=new node(m+1,e);
	}
	void up(int x,int nv){
		if(s==x&&e==x){
			v=ii(nv,s);return;
		}
		if(x<=m)l->up(x,nv);
		else r->up(x,nv);
		v=max(l->v,r->v);
	}
	ii qry(int x,int y){
		if(s==x&&e==y)return v;
		if(y<=m)return l->qry(x,y);
		if(x>m)return r->qry(x,y);
		return max(l->qry(x,m),r->qry(m+1,y));
	}
}*root;
 
int n,a,b;
int col[100005];
vector<ii> v;
vector<int> AL[100005];
 
bool dfs(int u){
	bool res=true;
	for(int v:AL[u]){
		if(col[v]==col[u])res=false;
		if(col[v]==-1){
			col[v]=1-col[u];
			res=res&&dfs(v);
		}
	}
	return res;
}
 
int main(){
	sf("%d",&n);
	for(int i=0;i<n;++i){
		sf("%d%d",&a,&b);
		v.pb(a,b);
	}
	ll ans=1;
	sort(all(v));
	root=new node(1,2*n);
	for(int i=0;i<n;++i){
		ii pr=root->qry(v[i].fi,v[i].se);
		if(v[i].fi<pr.fi&&pr.fi<v[i].se)pf("0\n"),exit(0);
		root->up(v[i].se,pr.se);
	}
	for(int i=0;i<n;++i){
		for(int j=i+1;j<n;++j){
			if(v[j].fi<v[i].se&&v[i].se<v[j].se){
				AL[i].pb(j);
				AL[j].pb(i);
			}
		}
	}
	memset(col,-1,sizeof col);
	for(int i=0;i<n;++i){
		if(col[i]==-1){
			col[i]=0;
          	dfs(i);
			ans*=2,ans%=mod;
		}
	}
	pf("%lld\n",ans);
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:58:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |  sf("%d",&n);
      |    ^
port_facility.cpp:60:5: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |   sf("%d%d",&a,&b);
      |     ^

• Subtask 1: 10 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 56
• Subtask 4: 0 / 22