Submission #127172

#	Time	Username	Problem	Language	Result	Execution time	Memory
127172		briansu	Port Facility (JOI17_port_facility)	C++14	100 / 100	2179 ms	134752 KiB

port_facility

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> ii;
#define REP(i, n) for(int i = 0;i < n;i ++)
#define REP1(i, n) for(int i = 1;i <= n;i ++)
#define FILL(i, n) memset(i, n, sizeof(i))
#define X first
#define Y second
#define pb push_back
#define SZ(_a) ((int)(_a).size())
#define ALL(_a) (_a).begin(), (_a).end()
#ifdef brian
#define IOS()
template<typename T>void _do(T &&x){cerr<<x<<endl;}
template<typename T, typename ...t>void _do(T &&x, t &&...X){cerr<<x<<", ";_do(X...);}
#define debug(...) {\
	fprintf(stderr, "%s - %d (%s) = ", __PRETTY_FUNCTION__, __LINE__, #__VA_ARGS__);\
	_do(__VA_ARGS__);\
}
#else
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0);
#define endl '\n'
#define debug(...)
#endif

const ll MAXn = 1e6 + 5;
const ll INF = ll(1e9);
const ll MOD = 1000000007;

vector<ll> v[MAXn];

ll in[MAXn], out[MAXn], vis[MAXn], ev[2 * MAXn];

namespace mnseg{
	int N;
	int d[4 * MAXn];
	void init(int n)
	{
		N = n;
		for(int i = 2 * n - 1;i > 0;i --)d[i] = INF;
	}
	void ins(ll x,ll k)
	{
		for(d[x += N] = k;x > 1;x >>= 1)d[x>>1] = min(d[x], d[x ^ 1]);
	}
	ll qr(ll l,ll r)
	{
		int ret = INF;
		for(l += N, r += N;l < r;l >>= 1, r >>= 1)
		{
			if(l & 1)ret = min(ret, d[l++]);
			if(r & 1)ret = min(ret, d[--r]);
		}
		return ret;
	}
};

namespace mxseg{
	int N;
	int d[4 * MAXn];
	void init(int n)
	{
		N = n;
		for(int i = 2 * n - 1;i > 0;i --)d[i] = 0;
	}
	void ins(ll x,ll k)
	{
		for(d[x += N] = k;x > 1;x >>= 1)d[x>>1] = max(d[x], d[x ^ 1]);
	}
	ll qr(ll l,ll r)
	{
		int ret = 0;
		for(l += N, r += N;l < r;l >>= 1, r >>= 1)
		{
			if(l & 1)ret = max(ret, d[l++]);
			if(r & 1)ret = max(ret, d[--r]);
		}
		return ret;
	}
};

ll n;
bool chk()
{
	vector<ll> a, b;
	REP1(i, 2 * n)
	{
		if(ev[i] < 0)
		{
			if(vis[-ev[i]])
			{
				if(b.back() != -ev[i])return 0;
				else b.pop_back();
			}
			else
			{
				if(a.back() != -ev[i])return 0;
				else a.pop_back();
			}
		}
		else
		{
			if(vis[ev[i]])b.pb(ev[i]);
			else a.pb(ev[i]);
		}
	}	
	return 1;
}

inline ll inter(ll i,ll j)
{
	return in[i] < in[j] && in[j] < out[i] && out[i] < out[j];
}

void dfs(ll now)
{
	mnseg::ins(out[now], INF);
	mxseg::ins(in[now], 0);
	while(1)
	{
		ll t = mnseg::qr(in[now] + 1, out[now]), x = -1;
		if(t < in[now])x = ev[t];
		else
		{
			t = mxseg::qr(in[now] + 1, out[now]);
			if(t > out[now])x = -ev[t];
		}
		if(x == -1)break;
		vis[x] = !vis[now];
		dfs(x);
	}
}

int main(){
	IOS();
	cin>>n;
	REP1(i, n)cin>>in[i]>>out[i], ev[in[i]] = i, ev[out[i]] = -i;

	ll ct = 0;
	FILL(vis, -1);
	mxseg::init(2 * (n + 2));
	mnseg::init(2 * (n + 2));
	REP1(i, n)mxseg::ins(in[i], out[i]);
	REP1(i, n)mnseg::ins(out[i], in[i]);
	REP1(i, n)if(vis[i] == -1)
	{
		ct ++;
		dfs(i);
	}
	debug(ct);
	if(!chk())cout<<0<<endl;
	else 
	{
		ll tt = 1;
		REP1(i, ct)tt = tt * 2  % MOD;
		cout<<tt<<endl;
	}
}

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