fand :: Bool -> Bool -> Bool fand a b | a == b = True | otherwise = false numberIntersections :: ((Integer, Integer), (Integer, Integer)) -> ((Integer, Integer), (Integer, Integer)) -> Int numberIntersections ls1 ls2 | fand (orien11 /= orien12) (orien21 /= orien22) = 1 | where orien11 = orientation (fst ls1) (snd ls1) (fst ls2) orien12 = orientation (fst ls1) (snd ls1) (snd ls2) orien21 = orientation (fst ls2) (snd ls2) (fst ls1) orien22 = orientation (fst ls2) (snd ls2) (snd ls1) onSegment :: (Integer, Integer) -> (Integer, Integer) -> (Integer, Integer) -> Int onSegment p q r = onSegmentFst :: Integer -> Integer -> Integer -> Bool onSegmentFst p q r = fand (onSegmentLE (fst q) (fst p) (fst r)) (onSegmentGE (fst q) (fst p) (fst r)) onSegmentSnd :: Integer -> Integer -> Integer -> Bool onSegmentSnd p q r = fand (onSegmentLE (snd q) (snd p) (snd r)) (onSegmentGE (snd q) (snd p) (snd r)) onSegmentGE :: Integer -> Integer -> Integer -> Bool onSegmentGE a b c = a >= (min b c) onSegmentLE :: Integer -> Integer -> Integer -> Bool onSegmentLE a b c = a <= (max b c) orientation :: (Integer, Integer) -> (Integer, Integer) -> (Integer, Integer) -> Int orientation p q r | value == 0 = 0 -- Collinear | value > 0 = 1 -- Clockwise | otherwise = -1 -- CounterClockwise where value = ((snd q) - (snd p)) * ((fst r) - (fst q)) - ((fst q) - (fst p)) * ((snd r) - (snd q)) dummyInput = [((0,9),(5,9)),((8,0),(0,8)),((9,4),(3,4)),((2,2),(2,1)),((7,0),(7,4)),((6,4),(2,0)),((0,9),(2,9)),((3,4),(1,4)),((0,0),(8,8)),((5,5),(8,2))]