UVa 545 - Heads

Accepted date: 2014-09-10
Ranking (as of 2014-09-10): 137 out of 609
Language: C++

/*
  UVa 545 - Heads

  To build using Visual Studio 2012:
    cl -EHsc -O2 UVa_545_Heads.cpp
*/

#include <cstdio>
#include <cmath>

const int n_max = 9000;

struct probability {
  double x_;
  int y_;
} probabilities[n_max + 1];

int main()
{
  const double eps = 1.0e-9; // without this value, the verdict was WA.
  int n, y = 0;
  double x = 1.0;
  probabilities[0].x_ = x; probabilities[0].y_ = y;
  for (n = 1; n <= n_max; n++) {
    x /= 2.0;
    if (x < 1.0) {
      x *= 10.0;
      y++;
    }
    probabilities[n].x_ = x; probabilities[n].y_ = y;
  }
  int r;
  scanf("%d", &r);
  while (r--) {
    int n;
    scanf("%d", &n);
    printf("2^-%d = %.3lfE-%d\n", n, probabilities[n].x_ + eps, probabilities[n].y_);
  }
  return 0;
}