Submission #1146554

#	Time	Username	Problem	Language	Result	Execution time	Memory
1146554		SmuggingSpun	Port Facility (JOI17_port_facility)	C++20	10 / 100	123 ms	436 KiB

port_facility

#include<bits/stdc++.h>
#define taskname "B"
using namespace std;
int n;
namespace sub1{
	void solve(){
		vector<int>a(n), b(n), p(n << 1 | 1);
		for(int i = 0; i < n; i++){
			cin >> a[i] >> b[i];
			p[b[i]] = -(p[a[i]] = i + 1);
		}
		int ans = 1 << n;
		for(int mask = (1 << n) - 1; mask > -1; mask--){
			vector<stack<int>>st(2);
			for(int i = 1; i <= (n << 1); i++){
				bool bit = bool(mask >> (abs(p[i]) - 1) & 1);
				if(p[i] > 0){
					st[bit].push(p[i]);
				}
				else{
					if(st[bit].top() != -p[i]){
						ans--;
						break;
					}
					st[bit].pop();
				}
			}			
		}
		cout << ans;
	}
}
namespace sub234{
	void solve(){
		
	}
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
	cin >> n;
	if(n <= 20){
		sub1::solve();
	}
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:40:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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