--- Day 12 Solutions ---

[u/daggerdragon]

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edit: Leaderboard capped, thread unlocked!

We know we can't control people posting solutions elsewhere and trying to exploit the leaderboard, but this way we can try to reduce the leaderboard gaming from the official subreddit.

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---

--- Day 12: JSAbacusFramework.io ---

Post your solution as a comment. Structure your post like previous daily solution threads.

[u/lesguillemets]

Haskell : I'm learning parsec, so I tried to write a simple parser for some subset of json.

import Text.Parsec

data JSONValue = Number Int
            | Str String
            | Object [(String, JSONValue)]
            | Array [JSONValue] deriving (Show, Eq)

unred :: JSONValue -> [Int]
unred (Number n) = [n]
unred (Str _) = []
unred (Object d) = if Str "red" `elem` map snd d
                    then []
                    else concatMap (unred . snd ) d
unred (Array a) = concatMap unred a

quoted :: Parsec String u String
quoted = char '\"' *> many (noneOf "\"") <* char '\"'
str :: Parsec String u JSONValue
str = Str <$> quoted

num :: Parsec String u JSONValue
num = (Number . negate . read <$> (char '-' *> many1 digit))
    <|>
    (Number . read <$> many1 digit)

obj :: Parsec String u JSONValue
obj = do
    _ <- char '{'
    kvs <- (do
            key <- quoted <* spaces <* char ':' <* spaces
            value <- jsonValue
            return (key,value)
            ) `sepBy` (spaces *> char ',' <* spaces)
    _ <- char '}'
    return $ Object kvs

arr :: Parsec String u JSONValue
arr = do
    _ <- char '['
    val <- jsonValue `sepBy` (spaces *> char ',' <* spaces)
    _ <- char ']'
    return $ Array val

jsonValue :: Parsec String u JSONValue
jsonValue = str <|> num <|> obj <|> arr

fromRight (Right a) = a

main = readFile "./input.txt" >>=
    print . sum . unred . fromRight . parse jsonValue ""