Submission #1157195

#	Time	Username	Problem	Language	Result	Execution time	Memory
1157195		SmuggingSpun	Sure Bet (CEOI17_sure)	C++20	20 / 100	50 ms	328 KiB

sure

#include<bits/stdc++.h>
#define taskname "B"
using namespace std;
template<class T>void maximize(T& a, T b){
	if(a < b){
		a = b;
	}
}
const int lim = 1e5 + 5;
const double E = 1e-6;
int n;
double a[lim], b[lim];
namespace sub1{
	vector<int>current(1, -1);
	double ans = 0;
	void play(int p){
		if(p > n){
			int cnt = 0;
			double A = 0, B = 0;
			for(int i = 1; i <= n; i++){
				if(current[i] > 0){
					cnt++;
					if(current[i] == 1){
						A += a[i];		
					}
					else if(current[i] == 2){
						B += b[i];
					}
					else{
						A += a[i];
						B += b[i];
						cnt++;
					}
				}
			}
			maximize(ans, min(A, B) - double(cnt));
			return;
		}
		for(int i = 0; i < 4; current.pop_back(), i++){
			current.emplace_back(i);
			play(p + 1);
		}
	}
	void solve(){
		play(1);
		cout << setprecision(4) << fixed << ans;
	}
}
namespace sub23{
	void solve(){
		sort(a + 1, a + n + 1, greater<double>());
		sort(b + 1, b + n + 1, greater<double>());
		a[0] = b[0] = 0;
		for(int i = 1; i <= n; i++){
			a[i] += a[i - 1];
			b[i] += b[i - 1];
		}
		double low = 1, high = 2e9;
		while(high - low > E){
			double mid = (low + high) / 2.0;
			bool can = false;
			for(int i = 1; i <= (n << 1); i++){
				if(min(a[n], b[n]) < mid + i * 10000){
					break;
				}
				if((lower_bound(a + 1, a + n + 1, mid + double(i)) - a) + (lower_bound(b + 1, b + n + 1, mid + double(i)) - b) <= i){
					can = true;
					break;
				}
			}
			if(can){
				low = mid;
			}
			else{
				high = mid;
			}
		}
		cout << setprecision(4) << fixed << low;
	}
}
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;
	for(int i = 1; i <= n; i++){
		cin >> a[i] >> b[i];
	}
	if(n <= 10){
		sub1::solve();
	}
	else{
		sub23::solve();
	}
}

Compilation message (stderr)

sure.cpp: In function 'int main()':
sure.cpp:84:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 0 / 40
• Subtask 3: 0 / 40