Submission #752859

#	Time	Username	Problem	Language	Result	Execution time	Memory
752859		dubabuba	Mobile (BOI12_mobile)	C++14	0 / 100	1081 ms	56772 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)
			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;
	}
	cout << R << '\n';
	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++)
      |                 ~~^~~~~~~~~~

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