Submission #964131

#	Time	Username	Problem	Language	Result	Execution time	Memory
964131		dubabuba	Mobile (BOI12_mobile)	C++14	100 / 100	778 ms	16144 KiB

mobile

#include <bits/stdc++.h>
using namespace std;

#pragma GCC optimize("O3")
#pragma GCC target("lzcnt", "popcnt")
 
typedef pair<int, int> pii;
#define x first
#define y second
#define MP make_pair
 
const int mxn = 1e6 + 10;
pii P[mxn];
int n, m;
 
bool can(double r) {
	double sus = 0;
	for(int i = 1; i <= n; i++) {
		double x = P[i].x;
		double y = abs(P[i].y);
		if(y > r) continue;
		double d = sqrt(r * r - y * y);
		double L = x - d, R = x + d;
		if(sus >= L) sus = max(sus, R);
	}
	return sus >= 1.0 * m;
}
 
int main() {
	cin >> n >> m;
	for(int i = 1; i <= n; i++)
		cin >> P[i].x >> P[i].y;
 
	double L = 0, R = 1e18;
	while(R - L > 0.0000001) {
		double M = (L + R) / 2;
		if(can(M)) R = M;
		else L = M;
	}
	printf("%.6lf\n", L);
	return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 4 / 4
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
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• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
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• Subtask 19: 5 / 5
• Subtask 20: 5 / 5
• Subtask 21: 5 / 5