Submission #518658

#	Time	Username	Problem	Language	Result	Execution time	Memory
518658		akhan42	Port Facility (JOI17_port_facility)	C++17	78 / 100	4131 ms	1048580 KiB

port_facility

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

#define F first
#define S second
#define forn(i, n) for(int i = 0; i < n; ++i)
#define forbn(i, b, n) for(int i = b; i < n; ++i)
#define sz(v) (int)v.size()
#define pb push_back
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define mp make_pair
#define at(m, p) (m.find(p) != m.end() ? m[p] : 0)

typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef long long ll;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

template <class T> inline void mineq(T &a, T b) { a = min(a, b); }
template <class T> inline void maxeq(T &a, T b) { a = max(a, b); }


const long long mod = 1000 * 1000 * 1000 + 7;

inline long long mpow(long long b, long long ex) {
    long long r = 1;

    while(ex) {
        if(ex & 1)
        	r = (r * b) % mod;
        ex = ex >> 1;
        b = (b * b) % mod;
    }
    return r;
}


struct Seg {
	int n;
	vector<set<ii>> sl;

	void init(int n, vii &vals) {
		this->n = n;
		sl.resize(4 * n);
		build(vals, 1, 0, n - 1);
	}

	void build(vii &vals, int v = 1, int tl = 0, int tr = -1) {
		if(tr == -1) tr = n - 1;
		if(tl == tr) {
			sl[v].insert(vals[tl]);
			return;
		}
		int tm = (tl + tr) >> 1;

		build(vals, 2 * v, tl, tm);
		build(vals, 2 * v + 1, tm + 1, tr);
		for(ii e: sl[2 * v])
			sl[v].insert(e);
		for(ii e: sl[2 * v + 1])
			sl[v].insert(e);
	}

	void query(vi &nb, int L, int R, int bd, bool is_left, int v = 1, int tl = 0, int tr = -1) {
		if(tr == -1) tr = n - 1;
		if(L > R)
			return;
		if(tl == L && tr == R) {
//			cerr << "otrezki " << L + 1 << ' ' << R + 1 << '\n';
			auto it = sl[v].lower_bound(mp(bd, 0));
			if(is_left) {
				for(; it != sl[v].end(); it++)
					nb.pb(it->S);
			} else {
				for(auto it2 = sl[v].begin(); it2 != it; it2++)
					nb.pb(it2->S);
			}
			return;
		}
		int tm = (tl + tr) >> 1;

		query(nb, L, min(R, tm), bd, is_left, 2 * v, tl, tm);
		query(nb, max(L, tm + 1), R, bd, is_left, 2 * v + 1, tm + 1, tr);
	}

	void del(int p, ii val, int v = 1, int tl = 0, int tr = -1) {
		if(tr == -1) tr = n - 1;
		sl[v].erase(val);
		if(tl == tr)
			return;

		int tm = (tl + tr) >> 1;
		if(p <= tm) {
			del(p, val, 2 * v, tl, tm);
		} else {
			del(p, val, 2 * v + 1, tm + 1, tr);
		}
	}
};


vector<int> att;
int ncomps = 0;
vii l2r, r2l, vlr;
Seg segl;


int ch(int c) {
	return c == 1 ? 2 : 1;
}


void my_push(queue<ii> &q, int node, int color) {
	int nodel = vlr[node].F, noder = vlr[node].S;
	segl.del(nodel, {noder, node});
	segl.del(noder, {nodel, node});

	q.push({node, color});
	att[node] = color;
}


void bfs(int root) {
	ncomps += 1;
//	cerr << "Comp: " << ncomps << '\n';

	queue<ii> q;
	my_push(q, root, 1);

	while(!q.empty()) {
		int node = q.front().F, color = q.front().S;
		int L = vlr[node].F, R = vlr[node].S;
		q.pop();
//		cerr << node << ' ';

		vi nbs;
		segl.query(nbs, L + 1, R - 1, R, true);
		segl.query(nbs, L + 1, R - 1, L, false);

		for(int nb: nbs) {
			my_push(q, nb, ch(color));
		}
	}
//	cerr << '\n';
}


void solve() {
	int n;
	cin >> n;
	l2r.resize(2 * n);
	att.assign(n, 0);

	forn(i, n) {
		int l, r;
		cin >> l >> r;
		l--; r--;
		l2r[l] = mp(r, i);
		l2r[r] = mp(l, i);
		vlr.eb(l, r);
	}

	segl.init(2 * n, l2r);

	forn(i, n) {
		if(!att[i]) {
			bfs(i);
		}
	}

	vector<array<int, 3>> v[2];

	forn(i, n) {
		int l = vlr[i].F, r = vlr[i].S;
		v[att[i] - 1].pb({l, 0, i});
		v[att[i] - 1].pb({r, 1, i});
	}

	sort(all(v[0]));
	sort(all(v[1]));
	bool bad = false;

//	forn(i, n) {
//		cerr << att[i] << '\n';
//	}

	forn(c, 2) {
		stack<int> st;
		for(auto ar: v[c]) {
			int op = ar[1], ind = ar[2];
			if(op == 0) {
				st.push(ind);
			} else {
				int ind_left = st.top();
				if(ind_left != ind) {
					bad = true;
					break;
				} else {
					st.pop();
				}
			}
		}
	}
	if(!bad) {
		cout << mpow(2, ncomps) << '\n';
	} else {
		cout << 0 << '\n';
	}
}


int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);

//	freopen("gathering.in", "r", stdin);
//	freopen("gathering.out", "w", stdout);

	int t = 1;
//	cin >> t;
	while(t--) {
		solve();
	}
}

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