Submission #964111

#	Time	Username	Problem	Language	Result	Execution time	Memory
964111		dubabuba	Mobile (BOI12_mobile)	C++14	0 / 100	1082 ms	55432 KiB

mobile

#include <bits/stdc++.h>
using namespace std;
 
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, l;
 
bool can(double r) {
	vector<pair<double, double>> v;
	for(int i = 1; i <= n; i++) {
		pii &p = P[i];
		double X = p.x;
		double Y = p.y;
 
		double sq = r * r - Y * Y;
		if(sq < 0) continue;
		sq = sqrt(sq);
 
		double f = X - sq, s = X + sq;
		if(f < 0) f = 0;
		if(s < 0) s = 0;
		if(f != s) v.push_back(MP(f, s));
	}
 
	sort(v.begin(), v.end());
	for(int i = 1; i < v.size(); i++) {
		if(v[i - 1].second < v[i].first) {
			if(v[i].first > 0.0) return 1;
			if(v[i - 1].second < (double) l) return 1;
		}
	}
	return 0;
}
 
int main() {
	cin >> n >> l;
	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)) L = M;
		else R = M;
	}
	printf("%.6lf\n", L);
	return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'bool can(double)':
mobile.cpp:31:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |  for(int i = 1; i < v.size(); i++) {
      |                 ~~^~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 4
• Subtask 3: 0 / 4
• Subtask 4: 0 / 4
• Subtask 5: 0 / 4
• Subtask 6: 0 / 5
• Subtask 7: 0 / 5
• Subtask 8: 0 / 5
• Subtask 9: 0 / 5
• Subtask 10: 0 / 5
• Subtask 11: 0 / 5
• Subtask 12: 0 / 5
• Subtask 13: 0 / 5
• Subtask 14: 0 / 5
• Subtask 15: 0 / 5
• Subtask 16: 0 / 5
• Subtask 17: 0 / 5
• Subtask 18: 0 / 5
• Subtask 19: 0 / 5
• Subtask 20: 0 / 5
• Subtask 21: 0 / 5