Submission #781094

#	Time	Username	Problem	Language	Result	Execution time	Memory
781094		uped	Mobile (BOI12_mobile)	C++14	100 / 100	367 ms	35300 KiB

mobile

#include<bits/stdc++.h>

using namespace std;

using ll = long long;

void fastio() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
}

int main() {
    fastio();
    int n, len;
    cin >> n >> len;
    vector<pair<ll, ll>> v(n);
    for (int i = 0; i < n; ++i) {
        int a, b;
        cin >> a >> b;
        v[i] = {a, b};
    }
    double l = 0.0, r = 1.5e9;
    while (r - l > 1e-3) {
        double radius = (l + r) / 2.0;
        double cur = 0;
        for (int j = 0; j < n; ++j) {
            ll x = v[j].first;
            ll y = v[j].second;
            double a = sqrt( radius * radius - y * y);
            if (x - a <= cur) cur = max(x + a, cur);
        }
        if (cur >= len) {
            r = radius;
        } else {
            l = radius;
        }
    }
    cout << fixed << setprecision(4) << l;
    return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 4 / 4
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
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• Subtask 6: 5 / 5
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• Subtask 20: 5 / 5
• Subtask 21: 5 / 5