Submission #469319

#	Time	Username	Problem	Language	Result	Execution time	Memory
469319		Return_0	Port Facility (JOI17_port_facility)	C++17	0 / 100	1 ms	332 KiB

port_facility

#pragma GCC optimize("Ofast,unroll-loops")
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma,tune=native")

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

using namespace std;
using namespace __gnu_pbds;

typedef int ll;
typedef long double ld;
typedef pair <ll, ll> pll;

#ifdef SINA
#define dbg(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1> void __f(const char* name, Arg1&& arg1) { cout << name << " : " << arg1 << std::endl; }
template <typename Arg1, typename... Args> void __f (const char* names, Arg1&& arg1, Args&&... args) {
	const char* comma = strchr(names + 1, ',');cout.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...); }
#define dbg2(x, j, n) cout<< #x << " : "; output((j), (n), x, 1); cout.flush();
#else
#define dbg(...) 0
#define dbg2(x, j, n) 0
#endif
#define SZ(x) ((ll)((x).size()))
#define File(s, t) freopen(s ".txt", "r", stdin); freopen(t ".txt", "w", stdout);
#define input(j, n, a) for (int _i = (j); _i < (n)+(j); _i++) cin>> a[_i];
#define output(j, n, a, t) for (int _i = (j); _i < (n)+(j); _i++) cout<< a[_i] << (((t) && _i != (n)+(j)-1)? ' ' : '\n');
#define kill(x) return cout<< (x) << endl, 0
#define cl const ll
#define fr first
#define sc second
#define lc (v << 1)
#define rc (lc | 1)
#define mid ((l + r) >> 1)
#define All(x) (x).begin(), (x).end()

cl inf = sizeof(ll) == 4 ? (1e9 + 10) : (3e18), mod = 1e9 + 7, MOD = 998244353;

template <class A,class B> ostream& operator << (ostream& out,const pair<A,B>&a){return out<<'('<<a.first<<", "<<a.second<<')';}
template <class A> ostream& operator << (ostream& out, const vector<A> &a) {
	out<< '['; for (int i = -1; ++i < int(a.size());) out<< a[i] << (i + 1 < int(a.size()) ? ", " : ""); return out<<']'; }
template <class T, typename _t = less <T> > using Tree = tree <T, null_type, _t, rb_tree_tag, tree_order_statistics_node_update>;

cl N = 1e6 + 7;

ll par [N], a [N << 1], A [N], B [N], n, _n;
vector <ll> vec1, vec2;

inline bool check (cl &i, cl &j) { return ((A[i] < A[j] && A[j] < B[i] && B[i] < B[j]) || (A[j] < A[i] && A[i] < B[j] && B[j] < B[i])); }
ll root (cl &v) { return par[v] ? par[v] = root(par[v]) : v; }
inline bool unite (ll v, ll u) {
	v = root(v); u = root(u);
	if (v == u) return false;
	return par[u] = v, _n--, true;
}

struct segtree {
	ll l, r, roo;
	bool empty;
	segtree *lt, *rt;
	inline segtree (cl &L = 1, cl &R = N - 2) : l(L), r(R), roo(0), empty(true) {}

	void build () {
		if (l == r) return;
		lt = new segtree (l, mid);
		rt = new segtree (mid + 1, r);
		lt->build(); rt->build();
	}

	void unify (cl &ql, cl &qr, cl &x) {
		if (r < ql || qr < l || empty) return;
		if (ql <= l && r <= qr) {
			if (roo) unite(x, roo);
			else {
				lt->unify(ql, qr, x);
				rt->unify(ql, qr, x);
				roo = x;
			}
			return;
		}
		lt->unify(ql, qr, x);
		rt->unify(ql, qr, x);
	}

	void upd (cl &pos, cl &x) {
		empty = false;
		if (l == r) { roo = x; return; }
		if (pos <= lt->r) lt->upd(pos, x);
		else rt->upd(pos, x);
		roo = root(lt->roo) == root(rt->roo) ? lt->roo : 0;
	}
} seg;

int main ()
{
	cin.tie(0)->sync_with_stdio(false);
	
	cin>> n; _n = n;
	for (ll i = 1; i <= n; i++) cin>> A[i] >> B[i], a[A[i]] = i, a[B[i]] = i + n;
	for (ll i = 1; i <= n + n; i++) {
		if (a[i] <= n) {
			if (vec1.empty() || !check(vec1.back(), a[i])) vec1.push_back(a[i]);
			else if (vec2.empty() || !check(vec2.back(), a[i])) vec2.push_back(a[i]);
			else kill(0);
		} else {
			if (!vec1.empty() && vec1.back() == a[i] - n) vec1.pop_back();
			else if (!vec2.empty() && vec2.back() == a[i] - n) vec2.pop_back();
			else kill(0);
		}
	}
	seg.r = n + n; seg.build();
	for (ll i = 1; i <= n + n; i++) if (a[i] <= n) {
		seg.upd(B[a[i]], a[i]);
		seg.unify(A[a[i]], B[a[i]], a[i]);
	}
	for (n = 1; _n--; n = (n + n) % mod);
	cout<< n << endl;

	cerr<< "\n" __TIMESTAMP__ " - Time elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";

	return 0;
}
/*
4
1 3
2 5
4 8
6 7

*/

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