68 lines
1.9 KiB
Agda
68 lines
1.9 KiB
Agda
module Day25
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import Prelude
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import Node
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import Aoc
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data Chunk : U where
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Key : List Int → Chunk
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Lock : List Int → Chunk
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-- cribbed from the idris library, it's late and I don't want to work thisout
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transpose : ∀ a. List (List a) → List (List a)
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transpose Nil = Nil
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transpose {a} (heads :: tails) = spreadHeads heads (transpose tails)
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where
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spreadHeads : List a → List (List a) → List (List a)
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spreadHeads Nil tails = tails
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spreadHeads (head :: heads) Nil = (head :: Nil) :: spreadHeads heads Nil
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spreadHeads (head :: heads) (tail :: tails) = (head :: tail) :: spreadHeads heads tails
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count : List Char → Int
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count cs = go cs 0
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where
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go : List Char → Int → Int
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go ('#' :: cs) acc = go cs (1 + acc)
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go _ acc = acc
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toChunk : List (List Char) → Chunk
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parseChunk : String → Chunk
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parseChunk text =
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let stuff = transpose $ map unpack $ split text "\n" in
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-- TODO - sort this out
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case map {List} count stuff of
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0 :: xs => Key $ map (count ∘ reverse) stuff
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xs => Lock xs
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parseFile : String → List Chunk
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parseFile text = do
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let parts = split (trim text) "\n\n"
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map parseChunk parts
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splitKeys : List Chunk → List (List Int) → List (List Int) → List (List Int) × List (List Int)
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splitKeys (Lock xs :: rest) locks keys = splitKeys rest (xs :: locks) keys
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splitKeys (Key xs :: rest) locks keys = splitKeys rest locks (xs :: keys)
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splitKeys Nil locks keys = (locks, keys)
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check : List Int → List Int → Int
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check Nil Nil = 1
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check (a :: as) (b :: bs) = if a + b <= 7 then check as bs else 0
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check _ _ = 0
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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 chunks = parseFile text
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let (locks,keys) = splitKeys chunks Nil Nil
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debugLog (length locks, length keys)
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let p1 = foldl _+_ 0 $ map (\ l => foldl _+_ 0 $ map (check l) keys) locks
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putStrLn $ "part1 " ++ show p1
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main : IO Unit
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main = do
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run "aoc2024/day25/eg.txt"
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run "aoc2024/day25/input.txt"
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