AdventOfCode/Haskell/2021/05/day5_2.hs

49 lines
1.8 KiB
Haskell

fand :: Bool -> Bool -> Bool
fand a b
| a == b = a
| otherwise = False
betweenxAndy :: Int -> Int -> Int -> Bool
betweenxAndy x y n = fand (n >= x) (n <= y)
between0And1 :: Int -> Bool
between0And1 = betweenxAndy 0 1
crossProduct :: (Integer, Integer) -> (Integer, Integer) -> Integer
crossProduct (x1, y1) (x2, y2) = x1*y2 - x2*y1
dotProduct :: (Integer, Integer) -> (Integer, Integer) -> Integer
dotProduct (x1, y1) (x2, y2) = x1*x2 + y1*y2
pointDifference :: (Integer, Integer) -> (Integer, Integer) -> (Integer, Integer)
pointDifference (x1, y1) (x2, y2) = (x1-x2, y1-y2)
pointSum :: (Integer, Integer) -> (Integer, Integer) -> (Integer, Integer)
pointSum (x1, y1) (x2, y2) = (x1+x2, y1+y2)
overlapNums :: ((Integer,Integer),(Integer,Integer)) -> ((Integer,Integer),(Integer,Integer)) -> Int
overlapNums (p, r) (q, s)
| collinear =
| paraNonInter = 0
| intersect = 1
| otherwise = 0
where bottom = crossProduct r s
tTop = crossProduct (pointDifference q p) s
top = crossProduct (pointDifference q p) r
collinear = fand (bottom == 0) (top == 0)
paraNonInter = fand (bottom == 0) (top /= 0)
u = top / bottom
t = tTop / bottom
intersect = fand (bottom /= 0) (fand (between0And1 u) (between0And1 t))
collineComp :: ((Integer,Integer),(Integer,Integer)) -> ((Integer,Integer),(Integer,Integer)) -> Int
collineComp (p, r) (q, s)
| fand (t0' < 0) (t1 >= 0) = 0-- overlapping
| fand (t0' >= 0) (t1 <= 1) = 0-- overlapping
| otherwise = 0 -- Disjoint
where t0 = (dotProduct (pointDifference p q) r) / dotProduct r r
t1 = (dotProduct (pointDifference (pointSum q s) p) r) / dotProduct r r
t0' = if t0 > t1 then t1 else t0
t1' = if t0 > t1 then t0 else t1
collineComp :: ((Integer,Integer),(Integer,Integer)) -> ((Integer,Integer),(Integer,Integer)) -> Int