To those who WA 8:
Try to change your epsilon to something else then 1e-14.
I changed that to 1e-8 and then I got AC.

Also, don't calculate S△ABC as 0.5*AB*AC! It should be 0.5*AB*AC*sin∠A

As I see - your advice is to use greater epsilon. May be it is better to avoid dangerous computations?

I've solved this problem in integers - so all comparations were EXACT =)

So, I think, the note about precision in problem text is superfluous.

How did you solved it? My first solution was with integers but than i noticed not all squares are axes aligned. :( Anyway, could you send me you solution? My email is  marshal at mail.bg. Thank you!

I got AC without epsilon;)