Submission #781060

#	Time	Username	Problem	Language	Result	Execution time	Memory
781060		uped	Mobile (BOI12_mobile)	C++14	0 / 100	1079 ms	87244 KiB

mobile

#include<bits/stdc++.h>

using namespace std;

using ll = long long;

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

void fileio(const string &name) {
    freopen((name + ".in").c_str(), "r", stdin);
    freopen((name + ".out").c_str(), "w", stdout);
}

int main() {
    int n, len;
    cin >> n >> len;
    vector<pair<int, int>> v(n);
    for (int i = 0; i < n; ++i) {
        int a, b;
        cin >> a >> b;
        v[i] = {a, b};
    }
    double l = 0.0, r = 1e12; // todo r
    for (int i = 0; i < 1000; ++i) {
        double radius = (l + r) / 2.0;
        map<double, int> m;
        for (auto [x, y] : v) {
            double a = sqrt(-1 * y * y + radius * radius);
            ++m[max(x - a, 0.0)];
            if (x + a <= len) {
                   --m[x + a + 1e-6];
            }
        }
        int cur = 0;
        bool ok = true;
        for (auto [_, cnt] : m) {
            cur += cnt;
            if (cur <= 0) {
                ok = false;
                break;
            }
        }
        if (ok) {
            r = radius;
        } else {
            l = radius;
        }
    }
    cout << setprecision(20) << r;
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:30:19: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   30 |         for (auto [x, y] : v) {
      |                   ^
mobile.cpp:39:19: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   39 |         for (auto [_, cnt] : m) {
      |                   ^
mobile.cpp: In function 'void fileio(const string&)':
mobile.cpp:13:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |     freopen((name + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:14:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |     freopen((name + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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