Submission #715666

#	Time	Username	Problem	Language	Result	Execution time	Memory
715666		MilosMilutinovic	Mobile (BOI12_mobile)	C++14	70 / 100	1082 ms	17724 KiB

mobile

#include <bits/stdc++.h>

using i64 = long long;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int n, L;
    std::cin >> n >> L;

    std::vector<int> x(n), y(n);
    for (int i = 0; i < n; i++) {
        std::cin >> x[i] >> y[i];
    }

    const double eps = 1E-4;

    std::function<bool(double)> check = [&](double r) {
        double f = 0;
        for (int i = 0; i < n; i++) {
            if (r * r >= (long double) y[i] * y[i]) {
                double p = std::sqrt(r * r - (long double) y[i] * y[i]);
                if (x[i] - p <= f) {
                    f = std::max(f, x[i] + p);
                }
            }
        }
        return f >= L;
    };

    double low = 0, high = 2E9, ans = -1;
    for (int i = 0; i < 200; i++) {
        double mid = (low + high) / 2;
        if (check(mid)) {
            ans = mid;
            high = mid;
        } else {
            low = mid;
        }
    }

    std::cout << std::fixed << std::setprecision(10) << ans << "\n";

    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:17:18: warning: unused variable 'eps' [-Wunused-variable]
   17 |     const double eps = 1E-4;
      |                  ^~~

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