Submission #953451

#	Time	Username	Problem	Language	Result	Execution time	Memory
953451		pcc	Port Facility (JOI17_port_facility)	C++17	22 / 100	27 ms	16488 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;

#define pii pair<int,int>
#define fs first
#define sc second
#define ll long long

const ll mod = 1e9+7;
const int mxn = 2024;

ll pw(ll a,ll b){
	ll re = 1;
	while(b){
		if(b&1)re = re*a%mod;
		b>>=1;
		a = a*a%mod;
	}
	return re;
}
ll mad(ll a,ll b){
	a += b;
	return a>=mod?a-mod:a;
}

pii arr[mxn];
int N;
vector<int> paths[mxn];
int col[mxn];

bool dfs(int now,int c = 1){
	bool flag = true;
	col[now] = c;
	for(auto nxt:paths[now]){
		if(!col[nxt])flag = flag&&dfs(nxt,-c);
		else if(col[nxt] != -c)flag = false;
	}
	return flag;
}

int main(){
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	cin>>N;
	for(int i = 1;i<=N;i++)cin>>arr[i].fs>>arr[i].sc;
	for(int i = 1;i<=N;i++){
		for(int j = i+1;j<=N;j++){
			auto ta = arr[i],tb = arr[j];
			if(ta.fs>tb.fs)swap(ta,tb);
			if(ta.sc<tb.sc&&ta.sc>tb.fs){
				paths[i].push_back(j);
				paths[j].push_back(i);
			}
		}
	}
	ll ans = 1;
	for(int i = 1;i<=N;i++){
		if(!col[i]){
			if(dfs(i)){
				ans = mad(ans,ans);
			}
			else ans = 0;
		}
	}
	cout<<ans;
}

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