Submission #683625

#	Time	Username	Problem	Language	Result	Execution time	Memory
683625		NK_	Port Facility (JOI17_port_facility)	C++17	0 / 100	1 ms	212 KiB

port_facility

// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>

using namespace std;

#define nl '\n'


const int MOD = 1e9+7;
int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	int N; cin >> N;

	int P = N;
	vector<int> E(2*N);
	for(int i = 0; i < N; i++) {
		int a, b; cin >> a >> b; --a, --b;
		E[a] = b;
		E[b] = -1;
	}

	set<int> S;
	for(int x = 0; x < 2*N; x++) {
		if (E[x] == -1) {
			S.erase(x);
		} else {
			int v = E[x];
			int amt = 0;
			for(const auto &c : S) {
				if (c < v) amt++;
				else break;
				if (amt == 2) break;
			}
			// cout << v << " " << amt << nl;

			if (amt == 2) {
				cout << 0 << nl;
				return 0;
			}

			if (amt == 1) P--;
			S.insert(v);
		}
	}


	int ans = 1;
	for(int i = 0; i < P; i++) ans = (2 * ans) % MOD;
	cout << ans << nl;

    return 0;
}

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