UVa 10964 - Strange Planet

Accepted date: 2016-10-05
Run Time: 0.000
Ranking (as of 2016-10-05): 8 out of 378
Language: C++11

/*
  UVa 10964 - Strange Planet

  To build using Visual Studio 2012:
    cl -EHsc -O2 UVa_10964_Strange_Planet.cpp
*/

#include <cstdio>
#include <cmath>

void get_coordinate(int c, int& x, int& y)
{
  int d = static_cast<int>((1.0 + sqrt(1.0 + static_cast<double>(c) * 2.0)) / 2.0);
    // c is in the d-th diamond shape from the origin
  if (2 * d * (d - 1) == c)
    d--;
  x = 1 - d, y = 1;
  int c_min = 2 * d * (d - 1) + 1, c_max = c_min + d - 1;
  if (c <= c_max)
    x += c - c_min, y += c - c_min;
  else {
    x += c_max - c_min, y += c_max - c_min;
    c_min = c_max, c_max += d;
    if (c <= c_max)
      x += c - c_min, y -= c - c_min;
    else {
      x += c_max - c_min, y -= c_max - c_min;
      c_min = c_max, c_max += d;
      if (c <= c_max)
        x -= c - c_min, y -= c - c_min;
      else {
        x -= c_max - c_min, y -= c_max - c_min;
        c_min = c_max, c_max += d;
        x -= c - c_min, y += c - c_min;
      }
    }
  }
#ifdef DEBUG
  printf("%d: (%d, %d)\n", c, x, y);
#endif
}

int main()
{
  while (true) {
    int a, b;
    scanf("%d %d", &a, &b);
    if (a == -1)
      break;
    int ax, ay, bx, by;
    get_coordinate(a, ax, ay);
    get_coordinate(b, bx, by);
    printf("%.2lf\n", hypot(static_cast<double>(ax - bx), static_cast<double>(ay - by)));
  }
  return 0;
}