Submission #670723

#	Time	Username	Problem	Language	Result	Execution time	Memory
670723		thiago_bastos	Wish (LMIO19_noras)	C++17	0 / 100	18 ms	340 KiB

noras

#include "bits/stdc++.h"

using namespace std;

#define INF 1000000000
#define INFLL 1000000000000000000ll
#define EPS 1e-9
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define pb push_back
#define fi first
#define sc second

using i64 = long long;
using u64 = unsigned long long;
using ld = long double;
using ii = pair<int, int>;

#define double ld

int n, radius;

double closest(int a, int b, int c, int d) {
	if(1ll*a*a+1ll*b*b <= 1ll * radius*radius) return 0;
	double l = 0, r = 1e9;
	while(fabs(l - r) > EPS) {
		double L = (2 * l + r) / 3.0, R = (2 * r + l) / 3.0;
		if(hypot(a + L * c, b + L * d) > hypot(a + R * c, b + R * d)) l = L;
		else r = R;
	}
	return r;
}

double firstSec(int a, int b, int c, int d, double k) {
	double l = 0, r = k;
	while(fabs(l - r) > EPS) {
		double m = (l + r) / 2;
		if(hypot(a + m * c, b + m * d) <= radius) r = m;
		else l = m;
	}
	return r;
}

double secondSec(int a, int b, int c, int d, double k) {
	double l = k, r = 1e9;
	while(fabs(l - r) > EPS) {
		double m = (l + r) / 2;
		if(hypot(a + m * c, b + m * d) > radius) r = m;
		else l = m;
	}
	return r;
}

void solve() {
	cin >> n >> radius;

	set<ii> sweep;
	int opening = 0, ans = 0;

	for(int i = 1; i <= n; ++i) {
		int a, b, c, d;

		cin >> a >> b >> c >> d;

		c -= a, d -= b;

		double k = closest(a, b, c, d);
		
		double l = firstSec(a, b, c, d, k);
		double r = secondSec(a, b, c, d, k);

		if(hypot(a + k * c, b + k * d) > radius) continue;	
		
		int L = (int)ceil(l), R = floor(r);
		
		if(L <= R) {
			sweep.emplace(l, -i);
			sweep.emplace(r, i);
		}
	}

	for(auto [x, k] : sweep) {
		opening += k < 0 ? 1 : -1;
		ans = max(ans, opening);
	}
	
	cout << ans << '\n';
}

int main() {
	ios_base :: sync_with_stdio(false);
	cin.tie(0);
	int t = 1;
	//cin >> t;
	while(t--) solve();
	return 0;
}

• Subtask 1: 0 / 23
• Subtask 2: 0 / 23
• Subtask 3: 0 / 15
• Subtask 4: 0 / 32
• Subtask 5: 0 / 7