Submission #924687

#	Time	Username	Problem	Language	Result	Execution time	Memory
924687		NK_	Sure Bet (CEOI17_sure)	C++17	0 / 100	0 ms	348 KiB

sure

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

using namespace std;

#define nl '\n'
#define pb push_back
#define sz(x) int(x.size())

using db = double;
using ll = long long;
template<class T> using V = vector<T>;
using vl = V<ll>;

const ll MUL = ll(1e4);

int main() {
	cin.tie(0)->sync_with_stdio(0);

	int N; cin >> N;

	vl A(N), B(N); for(int i = 0; i < N; i++) {
		double x, y; cin >> x >> y;
		A[i] = ll(db(MUL) * x), B[i] = ll(db(MUL) * y);
	}

	sort(rbegin(A), rend(A)); sort(rbegin(B), rend(B));

	for(int i = 1; i < N; i++) A[i] += A[i - 1];
	for(int i = 1; i < N; i++) B[i] += B[i - 1];

	// for(auto& x : A) cout << x << " ";
	// cout << endl;

	// for(auto& x : B) cout << x << " ";
	// cout << endl;

	ll ans = 0;
	for(int x = 2; x <= 2 * N; x++) {
		// cout << x << " ===> " << endl;
		// take x odds	

		auto F = [&](int i) {
			if (i <= 0) return -1LL;
			if (x - i <= 0) return -1LL;
			return min(A[i - 1] - x * 1LL * MUL, B[x - 1 - i] - x * 1LL * MUL);
		};

		int lo = max(1, x - N), hi = min(x - 1, N);
		while(lo < hi) {
			int mid = (lo + hi + 1) / 2;
			if (A[mid - 1] < B[x - 1 - mid]) lo = mid;
			else hi = mid - 1;
		}

		ans = max(ans, F(lo));
		ans = max(ans, F(lo - 1));

		// maximize min_{1 <= i <= x}(A[i - 1] - x, B[x - i] - x)
	} 

	ll ansr = ans % MUL, ansi = (ans - ansr) / MUL;

	db ANS = ansi + (ansr / db(MUL));

	printf("%.4lf", ANS);

	exit(0-0);
}

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