Submission #988846

#	Time	Username	Problem	Language	Result	Execution time	Memory
988846		_callmelucian	Balloons (CEOI11_bal)	C++14	100 / 100	276 ms	9256 KiB

bal

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

typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pld;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tt;

#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())

const ld INF = 1e18;
const ld eps = 1e-8;
const int mn = 2e5 + 5;

ll x[mn], maxR[mn];
ld rad[mn];

bool ok (int j, int i, ld tryR) {
    ld tmp = (x[i] - x[j]) * (x[i] - x[j]);
    return tmp - 4 * rad[j] * tryR >= -eps;
}

ld calc (int j, int i, ld L = 0, ld R = INF) {
    if (abs(L - R) < eps) return L;
    ld mid = (L + R) / 2;
    if (ok(j, i, mid + eps)) return calc(j, i, mid + eps, R);
    return calc(j, i, L, mid);
}

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

    int n; cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> x[i] >> maxR[i];
    rad[1] = maxR[1];

    cout << fixed << setprecision(9) << rad[1] << "\n";

    stack<int> st; st.push(1);
    for (int i = 2; i <= n; i++) {
        rad[i] = INF;
        int j = -1;
        while (st.size()) {
            j = st.top(); st.pop();
            ld cur = calc(j, i, 0, maxR[i]);
            rad[i] = min(rad[i], cur);
            if (rad[j] > rad[i]) {
                st.push(j);
                break;
            }
        }
        st.push(i);

        cout << rad[i] << "\n";
    }

    return 0;
}

• 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: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10