where nOccs = M.size $ occupiedInSight seats here
-neighbours (r, c) = S.delete (r, c) $ S.fromList [(r + dr, c + dc) | dr <- [-1, 0, 1], dc <- [-1, 0, 1]]
+neighbours (r, c) = S.delete (r, c)
+ $ S.fromList [ (r + dr, c + dc)
+ | dr <- [-1, 0, 1], dc <- [-1, 0, 1]]
neighbourhood seats here = M.restrictKeys seats (neighbours here)
occupiedNeighbours seats here = M.filter (== Occupied) $ neighbourhood seats here
manhattan (r1, c1) (r2, c2) = abs (r1 - r2) + abs (c1 - c2)
closestInDirection seats here direction = take 1 sortedSeats
- -- where seatsInDirection = M.keys $ M.filterWithKey (\o _ -> onSightLine here direction o) seats
where seatsInDirection = filter (onSightLine here direction) $ M.keys seats
sortedSeats = sortOn (manhattan here) seatsInDirection
closestInSight :: Seats -> Position -> (S.Set Position)
-closestInSight seats here = S.fromList $ concatMap (closestInDirection seats here) [d | d <- [Up .. UpLeft]]
+closestInSight seats here =
+ S.fromList $ concatMap (closestInDirection seats here)
+ [d | d <- [Up .. UpLeft]]
occupiedInSight :: Seats -> Position -> Seats
-occupiedInSight seats here = M.filter (== Occupied) $ M.restrictKeys seats $ closestInSight seats here
+occupiedInSight seats here = M.filter (== Occupied)
+ $ M.restrictKeys seats
+ $ closestInSight seats here
readGrid :: String -> (Seats, Position)