Submission #714922

#	Time	Username	Problem	Language	Result	Execution time	Memory
714922		MilosMilutinovic	Balloons (CEOI11_bal)	C++14	70 / 100	655 ms	8272 KiB

bal

#include <bits/stdc++.h>

using i64 = long long;

const double eps = 1E-6;

double solve(double x1, double r, double x2) {
    double low = 0, high = 1.001E9, R = 0;
    while (high - low >= eps) {
        double mid = (low + high) / 2;
        double dist = std::sqrt((long double) (x1 - x2) * (x1 - x2) + (long double) (r - mid) * (r - mid));
        if (dist >= r + mid) {
            R = mid;
            low = mid;
        } else {
            high = mid;
        }
    }
    return R;
}

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

    int n;
    std::cin >> n;

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

    std::vector<int> stk;
    for (int i = 0; i < n; i++) {
        double prv = 1.1E9;
        while (!stk.empty()) {
            int j = stk.back();
            double nr = solve(x[j], r[j], x[i]);
            r[i] = std::min(r[i], nr);
            if (r[i] >= r[j]) {
                stk.pop_back();
            } else {
                break;
            }
        }
        stk.push_back(i);
        std::cout << std::fixed << std::setprecision(5) << r[i] << "\n";
    }

    return 0;
}

Compilation message (stderr)

bal.cpp: In function 'int main()':
bal.cpp:36:16: warning: unused variable 'prv' [-Wunused-variable]
   36 |         double prv = 1.1E9;
      |                ^~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 10 / 10
• Subtask 10: 0 / 10