Submission #684608

#	Time	Username	Problem	Language	Result	Execution time	Memory
684608		aaggupta07	Mobile (BOI12_mobile)	C++17	100 / 100	355 ms	17092 KiB

mobile

// Source: https://usaco.guide/general/io

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

#define int long long
#define f first
#define s second
#define mp make_pair

constexpr int MAX_C = 1.5e9;
constexpr int MAX_N = 1e6;

using pi = pair<int, int>;
using pd = pair<double, double>;

int n, l;
pi towers[MAX_N];

bool check(double p) {
	// cout << "Called: " << p << endl;

	double best = 0;
	for(int i = 0; i < n; ++i) {
		if(abs(towers[i].s) >= p) continue;
		double dist = sqrt(p * p - towers[i].s * towers[i].s);
		double d1 = towers[i].f - dist, d2 = towers[i].f + dist;
		if(d1 <= best) best = max(best, d2);
	}

	if(best > l) return true;
	return false;
}

signed main() {
	ios::sync_with_stdio(false); cin.tie(nullptr);
	cin >> n >> l;
	for(int i = 0; i < n; ++i) cin >> towers[i].f >> towers[i].s;
	
	double le = 1e-4, r = MAX_C;
	while(r - le >= 1e-3) {
		double mid = (le + r) / 2;
		if(check(mid)) r = mid;
		else le = mid;
	}

	cout.precision(4);
	cout << fixed << le << '\n';
	return 0;
}

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