Submission #967269

#	Time	Username	Problem	Language	Result	Execution time	Memory
967269		v_matei	Mobile (BOI12_mobile)	C++17	Compilation error	0 ms	0 KiB

mobile

    #include <bits/stdc++.h>
    #include <cmath>
    #include <iomanip>
     
    #define ll long long
    #define ull unsigned long long
    #define pdd std::pair<double, double>
     
    #define NMAX 1e6
    #define INF 2e9
     
    struct Tower {
      double x, y;
    };
    struct Seg {
      double st, fn;
    };
    double n, l;
    std::vector<Tower> s;
     
    void citire() {
      std::cin >> n >> l;
      s.resize(n);
      for (int i = 0; i < n; i++) {
        std::cin >> s[i].x >> s[i].y;
      }
    }
     
    double b_search(double lo, double hi, std::function<bool(double)> f) {
      for (int i = 1; hi - lo > 0.001; i++) {
        double mid = (lo + hi) / 2;
        if (f(mid))
          hi = mid;
        else
          lo = mid;
      }
      return lo;
    }
     
    bool find_point(double k) {
      std::vector<Seg> segs;
      for (Tower &it : s) {
        if (k * k < it.y * it.y)
          continue;
        double max_dx = sqrt(k * k - it.y * it.y);
        segs.push_back({it.x - max_dx, it.x + max_dx});
        if (segs.back().st < 0 && segs.back().fn > l)
          return 1;
      }
      double pre = 0;
      for (Seg &it : segs) {
        if (pre >= l)
          return 1;
        if (pre >= it.st)
          pre = std::max(pre, it.fn);
      }
      return pre > l;
    }
     
    int main() {
      ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
      citire();
      double k = b_search(0, INF, find_point);
      std::cout << std::fixed << std::setprecision(10) << k;
      return 0;
    }

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:61:7: error: 'ios' has not been declared
   61 |       ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
      |       ^~~
mobile.cpp:61:31: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
   61 |       ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
      |                               ^~~
      |                               std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:75,
                 from mobile.cpp:1:
/usr/include/c++/10/iostream:60:18: note: 'std::cin' declared here
   60 |   extern istream cin;  /// Linked to standard input
      |                  ^~~
mobile.cpp:61:42: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   61 |       ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
      |                                          ^~~~
      |                                          std::cout
In file included from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:75,
                 from mobile.cpp:1:
/usr/include/c++/10/iostream:61:18: note: 'std::cout' declared here
   61 |   extern ostream cout;  /// Linked to standard output
      |                  ^~~~