ionchy
/
adventofcode
1
0
Fork 0
Code

Day 03 - now with IntMap!

This commit is contained in:
Jonathan Chan 2018-12-03 10:08:06 -08:00
parent e296528b63
commit 6fa7a855ee
2 changed files with 13 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
README.md
View File

@ -10,7 +10,7 @@ To arrive at [⟨ortho|normal⟩](https://hilb.ert.space) as December comes.
|-----|-------------|------------| |-----|-------------|------------|
| 01 | < 0.1 | | 01 | < 0.1 |
| 02 | < 0.1 | | 02 | < 0.1 |
| 03 | | | 03 | ~ 2 |
| 04 | | | 04 | |
| 05 | | | 05 | |
| 06 | | | 06 | |

31
src/Day03.hs
View File

@ -1,33 +1,24 @@
module Day03 (main) where module Day03 (main) where
import Data.Text (split, pack, unpack) import Data.Text (empty, split, pack, unpack)
import Data.IntMap (IntMap, fromListWith, size, notMember)
import qualified Data.IntMap as M (filter)
type Claim = (Int, Int, Int, Int, Int) -- id, left, top, width, height type Claim = (Int, [Int])
(%) = mod
(//) = div
parse :: String -> Claim parse :: String -> Claim
parse str = parse str =
let i:l:t:w:h:[] = map (read . unpack) . tail . split (flip elem $ "#@,:x") . pack . filter (/= ' ') $ str let i:l:t:w:h:[] = map (read . unpack) . filter (/= empty) . split (flip elem $ " #@,:x") . pack $ str
in (i, l, t, w, h) in (i, [r * 1000 + c | r <- [t .. t + h - 1], c <- [l .. l + w - 1]])
doesClaim :: Int -> Claim -> Bool overlapMap :: [Claim] -> IntMap Int
doesClaim cell (_, left, top, width, height) = overlapMap = M.filter (> 1) . fromListWith (+) . (flip zip) (repeat 1) . concat . map snd
let row = cell // 1000
col = cell % 1000
in (row >= top) && (row < top + height) && (col >= left) && (col < left + width)
claimCount :: [Claim] -> Int -> Int
claimCount claims cell = length . filter (doesClaim cell) $ claims
part1 :: [Claim] -> Int part1 :: [Claim] -> Int
part1 claims = length . filter id . map ((> 1) . claimCount claims) $ [0 .. 1000 * 1000 - 1] part1 = size . overlapMap
part2 :: [Claim] -> Claim part2 :: [Claim] -> Int
part2 claims = filterOverlaps 0 claims part2 claims = fst . head . filter (all (flip notMember $ overlapMap claims) . snd) $ claims
where filterOverlaps cell acc =
let newAcc = if claimCount claims cell > 1 then filter (not . doesClaim cell) acc else acc
in if length newAcc == 1 then head newAcc else filterOverlaps (cell + 1) newAcc
main :: IO () main :: IO ()
main = do main = do