Submission #427119

#	Time	Username	Problem	Language	Result	Execution time	Memory
427119		jamezzz	Port Facility (JOI17_port_facility)	C++17	22 / 100	324 ms	16436 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

int n,a,b;
int col[2005];
vector<ii> v;
vector<int> AL[2005];

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));
	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;
			if(dfs(i))ans*=2,ans%=mod;
			else pf("0\n"),exit(0);
		}
	}
	pf("%lld\n",ans);
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:34:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |  sf("%d",&n);
      |    ^
port_facility.cpp:36:5: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |   sf("%d%d",&a,&b);
      |     ^

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