56 lines
1.7 KiB
Agda
56 lines
1.7 KiB
Agda
module Day11
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import Prelude
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import Node
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import Aoc
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import SortedMap
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infixl 7 _%_
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pfunc _%_ : Int → Int → Int := `(x,y) => x % y`
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-- should have a few more foreign functions and do this in newt
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pfunc divide uses (_,_) : String → String × String := `(s) => {
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let l = s.length/2|0
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return _$2C_(undefined, undefined, s.slice(0,l), s.slice(l))
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}`
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foldMap : ∀ a b. {{Ord a}} {{Eq a}} → (b → b → b) → SortedMap a b → List (a × b) → SortedMap a b
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foldMap f m Nil = m
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foldMap f m ((a,b) :: xs) = case lookupMap a m of
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Nothing => foldMap f (updateMap a b m) xs
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Just (_, b') => foldMap f (updateMap a (f b' b) m) xs
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step : List (Int × Int) → List (Int × Int)
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step = go Nil
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where
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go : List (Int × Int) → List (Int × Int) → List (Int × Int)
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go acc Nil = acc
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go acc ((0,c) :: xs) = go ((1,c) :: acc) xs
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go acc ((x,c) :: xs) =
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let str = show x in
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if slen str % 2 == 0
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then let (a,b) = divide str in go ((stringToInt a,c) :: (stringToInt b,c) :: acc) xs
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else go ((2024 * x,c) :: acc) xs
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iter : Int → SortedMap Int Int → Int
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iter count parts = let x = go count parts in foldl _+_ 0 $ map snd $ toList x
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where
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go : Int → SortedMap Int Int → SortedMap Int Int
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go 0 stuff = stuff
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go x stuff = go (x - 1) $ foldMap _+_ EmptyMap $ step $ toList stuff
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run : String -> IO Unit
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run fn = do
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putStrLn fn
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text <- readFile fn
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let stuff = foldMap _+_ EmptyMap $ map (\ x => (stringToInt x, 1)) $ split (trim text) " "
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let p1 = iter 25 stuff
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putStrLn $ "part1 " ++ show p1
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let p2 = iter 75 stuff
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putStrLn $ "part2 " ++ show p2
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main : IO Unit
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main = do
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run "aoc2024/day11/eg.txt"
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run "aoc2024/day11/input.txt"
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