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## Discussion of Problem 1294. Mars Satellites

whats in 3 test?? what s wrong?
Posted by ivan 3 Apr 2012 22:40
my code c#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace kyrsach1294
{
class Program
{
static int Main(string[] args)
{ int a,b,c,d;
string[] dlins = Console.ReadLine().Split(' ');
a = int.Parse(dlins);
b = int.Parse(dlins);
c = int.Parse(dlins);
d = int.Parse(dlins);
if (a * b==c * d)
{
{
Console.WriteLine("Impossible.");
return 0;
}
}

double s,s1,s2;
s1 = c * d / (c * d - a * b);

s2 = a * b / (c * d - a * b);
s = s1*a*a+s1*b*b-s2*c*c-s2*d*d;
if (s < 0)
{
Console.WriteLine("Impossible.");
return 0;
}

s = Math.Sqrt(s) * 1000;
Console.WriteLine("Distance is "+answer+" km.");
return 0;
}
}
}

Edited by author 03.04.2012 22:40
Re: whats in 3 test?? what s wrong?
Posted by ZamNick 13 Nov 2012 03:22
Hi, guy.
Don't use Convert.ToInt32 for answer, it's wrong. You should go some other way. For example, first, I used double instead of int, and a small value EPS = 1e-9.
if(Math.Abs(a*b - c*d) < EPS)
{
Console.WriteLine("Impossible.");
return;
}

Second, I don't used :
if (s < 0)
{
Console.WriteLine("Impossible.");
return 0;
}
It's not necessary. I passed without this.

Third, you should approximate on another way. Convert.ToInt32 don't work correct, but I found the simple trick :
bool flag = false;
x = Math.Sqrt((a*b*(c*c + d*d) - c*d*(a*a + b*b)) / (a*b - c*d));
int y = ((int)(x * 10000.0)) % 10;
if (y >= 5) flag = true;
int ans = (int)(x * 1000.0);
if (flag == true) ++ans;
Console.WriteLine("Distance is {0} km.", ans);

I hope that I helped you. If you will get WA again and again I can send you correct code on your email.

4615234    03:01:21
13 ноя 2012    ZamNick    1294. Марсианские спутники    C#    Accepted
0.109    2 096 КБ