Quiz2.hs

type S = ((Int,Int),(Int,Int),(Int,Int))

guess :: S -> S
guess ((a1,a2),(b1,b2),(c1,c2)) =
  case (a1+b1) `compare` (b2+c1) of
    EQ ->
      if b1 < b2
      then ((100,99),(99,100),(99,100))
      else ((99,100),(100,99),(100,99))
    LT ->
      case (a1+c1) `compare` (a2+c2) of
        EQ -> ((99,100),(99,100),(100,99))
        LT -> ((99,100),(99,100),(99,100))
        GT -> ((100,99),(99,100),(100,99))
    GT ->
      case (a1+c1) `compare` (a2+c2) of
        EQ -> ((100,99),(100,99),(99,100))
        LT -> ((99,100),(100,99),(99,100))
        GT -> ((100,99),(100,99),(100,99))

test :: S -> Bool
test s = guess s == s

testAll :: Bool
testAll = and [test (as,bs,cs) | as <- xs, bs <- xs, cs <- xs]
  where xs = [(99,100),(100,99)]