Submission #249814

#	Time	Username	Problem	Language	Result	Execution time	Memory
249814		Blagojce	Port Facility (JOI17_port_facility)	C++11	22 / 100	6123 ms	898848 KiB

port_facility

#include <bits/stdc++.h> 
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define pb push_back
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x), end(x)
#include <time.h>
#include <cmath>

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,ll> pii;

const int i_inf = 1e9;
const ll inf = 1e18;
const ll mod = 1000000007;
const ld eps = 1e-13;
const ld pi  = 3.14159265359;
 
mt19937 _rand(time(NULL));
clock_t timer = clock();
const int mxn = 4e6;
 
const ll A = 911382323;
const ll B = 972663749;
 
ll modpow(ll x, ll n){
	if(n == 0) return 1%mod;
	ll u = modpow(x, n/2);
	u = (u * u) % mod;
	if(n % 2) u = (u * x) % mod;
	return u;
}
ll inverse(ll x){
	return modpow(x, mod-2);
}
ll add(ll ans, ll val){
	ans = (ans + val) % mod;
	return ans;
}
ll mul(ll ans, ll val){
	ans = (ans * val) % mod;
	return ans;
}
ll sub(ll ans, ll val){
	ans = (ans - val) % mod;
	if(ans < 0) ans += mod;
	return ans;
}
ll _div(ll ans, ll val){
	ans = (ans * inverse(val)) % mod;
	return ans;
}
ll fakt[mxn];
ll bc(ll n, ll k){
	return (fakt[n]*inverse((fakt[k]*fakt[n-k])%mod))%mod;
}
ll sq(ll x){
	return x*x;
}
ll rsum(ll a, ll b){
	return (b-a+1)*(a+b)/2;
}
void prec(){
	fakt[0] = 1;
	fr(i, 1, mxn){
		fakt[i] = mul(fakt[i-1], i);
	}
}
int a[mxn], b[mxn];
vector<int> g[mxn];
int col[mxn];
void dfs(int u){
	for(auto e : g[u]){
		if(col[e] == -1){
			col[e] = col[u]^1;
			dfs(e);
		}
		else if(col[u] == col[e]){
			cout<<0<<endl;
			exit(0);
		}
	}
}


void solve(){
	int n;
	cin >> n;
	
	int val[2*n+1];
	memset(val, 0, sizeof(val));
	int id[2*n+1];
	fr(i, 0, n){
		cin >> a[i] >> b[i];
		val[a[i]] = +1;
		val[b[i]] = -1;
		id[a[i]] = id[b[i]] = i;
	}
	
	set<int> S;
	
	fr(i, 1, 2*n+1){
		if(val[i] == 0) continue;
		
		if(val[i] > 0){
			S.insert(-i);
		}
		else{
			int c = id[i];
			int l = a[c];
			S.erase(-l);
			for(auto u : S){
				if(-u > l){
					g[c].pb(id[-u]);
					g[id[-u]].pb(c);
				}
				else break;
			}
		}
	}	
	ll ans = 1;
	memset(col, -1, sizeof(col));
	fr(i, 0, n){
		if(col[i] != -1) continue;
		col[i] = 0;
		dfs(i);
		ans = mul(ans, 2);
	}
	
	cout<<ans<<endl;
}




int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	solve();
	return 0;
	
}

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