Submission #1312653

#	Time	Username	Problem	Language	Result	Execution time	Memory
1312653		ericl23302	Balloons (CEOI11_bal)	C++20	20 / 100	227 ms	11212 KiB

bal

#include <bits/stdc++.h>

using namespace std;

#define double long double

bool checkIntersect(double x1, double y1, double x2, double y2) {
    return (sqrt(pow((double)(x2 - x1), (double)(2)) +
                 pow(y2 - y1, (double)(2))) < (double)(y1 + y2));
};

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    double n;
    cin >> n;
    vector<pair<double, double>> balloons(n);
    for (auto& i : balloons) cin >> i.first >> i.second;

    vector<double> res(n);
    stack<pair<double, double>> stk;
    for (double i = 0; i < n; ++i) {
        while (stk.size() >= 2) {
            auto two = stk.top();
            stk.pop();
            auto one = stk.top();
            double l = 0, h = balloons[i].second;
            bool res1 = false, res2 = false;
            while (h - l > 1e-6) {
                double mid = (l + h) / 2;
                res1 = checkIntersect(one.first, one.second, balloons[i].first,
                                      mid),
                res2 = checkIntersect(two.first, two.second, balloons[i].first,
                                      mid);
                if (res1 && res2)
                    h = mid;
                else if (!res1 && !res2)
                    l = mid;
                else
                    break;
            }

            if (res2 && !res1) {
                stk.push(two);
                break;
            }
        }

        if (stk.empty()) {
            res[i] = balloons[i].second;
            stk.push(balloons[i]);
            continue;
        }

        auto cur = stk.top();
        double l = 0, h = balloons[i].second;
        while (h - l > 1e-6) {
            double mid = (l + h) / 2;
            if (checkIntersect(cur.first, cur.second, balloons[i].first, mid))
                h = mid;
            else
                l = mid;
        }
        res[i] = l;
        stk.emplace(balloons[i].first, l);
    }

    for (auto& i : res) cout << fixed << setprecision(3) << i << '\n';

    return 0;
}

• 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