Project Euler Problem 091

import Data.List
import Data.Complex

eps :: Double
eps = 1e-6
-- 直角の判定1
isRight :: Complex Double -> Complex Double -> Bool
isRight l r = imp l r
              || imp (r-l) (-l) -- マイナスをつけ忘れてた頭がこんがらがる
              || imp r (r-l)
  where imp l r = abs(phase(l/r)-pi/2) Complex Double -> Bool
isRight2 l r = 
  (((realPart l /= realPart r)||(imagPart l /= imagPart r))
   &&
   ((realPart l /= 0)||(imagPart l /= 0))
   &&
   ((realPart r /= 0)||(imagPart r /= 0))
  )
  &&
  (
    (dot l r == 0)
    || (dot (r-l) l == 0)
    || (dot (r-l) r == 0)
  )
-- -}
-- z1*z2*cosΘ
dot :: RealFloat a => Complex a -> Complex a -> a
dot x y= realPart $ ((conjugate x)*y)
-- z1*z2*sinΘ
cross :: RealFloat a => Complex a -> Complex a -> a
cross x y = imagPart $ ((conjugate x)*y)

r :: [Double]
r = [0..50]
ans1 :: Int
ans1 = length $ nub $ sort $ [((x1,y1),(x2,y2))|
                             x1 <- r,
                             x2 <- r,
                             x1 <= x2,
                             y1 <- r,
                             y2 <- r,
                             y1 >= y2,
                             isRight2 (x1 :+ y1) (x2 :+ y2)]
-- 14234       
main :: IO ()
main = print ans1