WarpingPath

WarpingPath.hs

warpingPath :: Array (Int,Int) Int -> [(Int,Int)]
warpingPath arr = go (w,h) []
  where
    (_,(w,h)) = bounds arr
    go p@(x,y) xs
      | x == 0 && y == 0 = p : xs
      | otherwise = go minVal (minVal : xs)
      where
        minVal = minimumBy (comparing (arr !)) [down,downLeft,left]
        down = (max 0 (x-1),max 0 y)
        left = (x,max 0 (y-1))
        downLeft = (max 0 (x-1),max 0 (y-1))