Project Euler 解答

Project Euler Problem 091

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

since 2013