Submission #1280840

#	Time	Username	Problem	Language	Result	Execution time	Memory
1280840		Lithanium	Balloons (CEOI11_bal)	C++20	20 / 100	642 ms	4768 KiB

bal

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

double calc(int x1, double r1, int x2, double r2) {
    // binary search on circle size
    double low = 0, high = r2;
    for (int t = 0; t < 60; t ++) {
        double mid = (low + high)/2;
        // xcoordinate at (x1, r1) and (x2, mid)
        double dist = pow((double)(x1 - x2), 2) + pow(r1 - mid, 2);
        if (pow(r1 + mid, 2) <= dist) low = mid;
        else high = mid;
    }
    return low;
}

int main() {
    int N;
    cin >> N;
    stack<pair<int, double>> st; // {x coordinate, size}
    for (int i = 1; i <= N; i ++) {
        int x;
        double r;
        cin >> x >> r;
        while (st.size() >= 2) {
            // check if the last thing can be popped off
            auto [a, b] = st.top();
            st.pop();
            auto [c, d] = st.top();
            st.push({a, b});
            if (calc(a, b, x, r) > calc(c, d, x, r)) {
                st.pop();
            } else break;
        }
        // check the top 2 in the stack
        if (st.empty()) {
            cout << fixed << setprecision(3) << r << "\n";
            st.push({x, r});
        } else {
            auto [a, b] = st.top();
            r = calc(a, b, x, r);
            cout << fixed << setprecision(3) << r << "\n";
            st.push({x, r});
        }
    }
}

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