patrickaldis/garnet
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Solve day 1 part 2

Browse Source
This commit is contained in:
George Thomas 2025-12-02 01:44:53 +00:00
parent fd2b0ed0cc
commit 0efd99220e
1 changed files with 19 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
app/Main.hs
View File

@ -1,6 +1,7 @@
module Main (main) where module Main (main) where
import Control.Monad.State import Control.Monad.State
import Data.Bifunctor
import Data.Traversable import Data.Traversable
import Text.Read (readMaybe) import Text.Read (readMaybe)
@ -19,8 +20,21 @@ main = do
. sum . sum
. flip evalState 50 . flip evalState 50
$ for input \(d, i) -> state \p -> $ for input \(d, i) -> state \p ->
let p' = step i d p let (_, p') = step i d p
in (Count if p' == 0 then 1 else 0, p') in (Count if p' == 0 then 1 else 0, p')
print
. sum
. flip evalState 50
$ for input \(d, i) -> state \p ->
let (c, p') = step i d p
c' = case d of
R -> abs c
L ->
if
| p == 0 -> abs c - 1
| p' == 0 -> abs c + 1
| otherwise -> abs c
in (c', p')
data Direction = L | R data Direction = L | R
deriving (Eq, Ord, Show) deriving (Eq, Ord, Show)
@ -34,7 +48,7 @@ newtype Inc = Inc Int
newtype Count = Count Int newtype Count = Count Int
deriving newtype (Eq, Ord, Show, Num) deriving newtype (Eq, Ord, Show, Num)
step :: Inc -> Direction -> Pos -> Pos step :: Inc -> Direction -> Pos -> (Count, Pos)
step (Inc i) d (Pos p) = Pos case d of step (Inc i) d (Pos p) = bimap Count Pos case d of
L -> (p - i) `mod` 100 L -> (p - i) `divMod` 100
R -> (p + i) `mod` 100 R -> (p + i) `divMod` 100