Submission #502441

#	Time	Username	Problem	Language	Result	Execution time	Memory
502441		chenwz	Mobile (BOI12_mobile)	C++11	100 / 100	372 ms	24604 KiB

mobile

// BalticOI2012 - Mobile
#include <bits/stdc++.h>
using namespace std;
using LL = long long;
#define _for(i, a, b) for (int i = (a); i < (int)(b); ++i)
int main() {
  int N, L;
  scanf("%d%d", &N, &L);
  vector<int> X(N), Y(N);
  _for(i, 0, N) scanf("%d%d", &X[i], &Y[i]);
  double l = 1, r = 1.5e9;
  while (r - l > 1e-3) {
    double m = (l + r) / 2, right = 0;
    _for(i, 0, N) {
      double y = Y[i], dx = sqrt(m * m - y * y), a = X[i] - dx, b = X[i] + dx;
      if (a <= right) right = max(right, b);
      if (right >= L) break;
    }
    (right >= L ? r : l) = m;
  }
  printf("%.4lf\n", l);
  return 0;
}
// 499716 Mobile (BOI12_mobile) C++11 100 / 100 405ms  27384KB

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:8:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |   scanf("%d%d", &N, &L);
      |   ~~~~~^~~~~~~~~~~~~~~~
mobile.cpp:10:22: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |   _for(i, 0, N) scanf("%d%d", &X[i], &Y[i]);
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~

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