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newt/aoc2023/Day2.newt
Steve Dunham d5a4d6253f port aoc2023 day4
more stuff in Prelude, typechecking fixes, solving autos
2024-11-30 10:27:06 -08:00

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module Day2
import Prelude
import Node
Draw : U
Draw = Int × Int × Int
data Game : U where
MkGame : Int -> List Draw -> Game
-- Original had class and instance...
-- Add, Sub, Mul, Neg
max : Int -> Int -> Int
max x y = case x < y of
True => y
False => x
pfunc repr : {a : U} -> a -> String := `(a,o) => ''+o`
pfunc jrepr : {a : U} -> a -> String := `(a,o) => JSON.stringify(o, null, ' ')`
pfunc toInt : String -> Int := `s => Number(s)`
maxd : Draw -> Draw -> Draw
maxd (a,b,c) (d,e,f) = (max a d, max b e, max c f)
lte : Draw -> Draw -> Bool
lte (a,b,c) (d,e,f) = a <= d && b <= e && c <= f
parseColor : String -> Either String Draw
parseColor line = case split line " " of
(n :: "red" :: Nil) => Right (toInt n,0,0)
(n :: "green" :: Nil) => Right (0,toInt n,0)
(n :: "blue" :: Nil) => Right (0,0,toInt n)
x => Left $ "Bad draw" ++ repr x
-- FIXME implicit isn't being solved in time here.
parseDraw : String -> Either String Draw
parseDraw line =
case mapM {Either String} parseColor $ split line ", " of
Right parts => Right $ foldl maxd (0,0,0) parts
Left err => Left err
parseGame : String -> Either String Game
parseGame line =
-- Need the Idris | sugar...
case split line ": " of
-- this is splitting on the Nil instead of the a
(a :: b :: Nil) => case split a " " of
("Game" :: ns :: Nil) =>
let num = toInt ns in
case mapM {Either String} parseDraw $ split b "; " of
Right parts => Right $ MkGame num parts
Left err => Left err
_ => Left "No Game"
_ => Left $ "No colon in " ++ line
part1 : List Game -> Int
part1 Nil = 0
part1 (MkGame n parts :: rest) =
let total = foldl maxd (0,0,0) parts in
case lte total (12,13,14) of
True => n + part1 rest
False => part1 rest
part2 : List Game -> Int
part2 Nil = 0
part2 (MkGame n parts :: rest) =
case foldl maxd (0,0,0) parts of
(a,b,c) => a * b * c + part2 rest
run : String -> IO Unit
run fn = do
putStrLn fn
text <- readFile fn
case mapM {Either String} parseGame (split (trim text) "\n") of
Left err => putStrLn $ "fail " ++ err
Right games => do
putStrLn "part1"
printLn (part1 games)
putStrLn "part2"
printLn (part2 games)
main : IO Unit
main = do
run "aoc2023/day2/eg.txt"
run "aoc2023/day2/input.txt"