Done day 9

[advent-of-code-18.git] / src / advent08 / advent08-treelibrary.hs

diff --git a/src/advent08/advent08-treelibrary.hs b/src/advent08/advent08-treelibrary.hs
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+{-# LANGUAGE OverloadedStrings #-}
+
+-- import Data.List
+
+import Data.Tree (Tree(Node), rootLabel, subForest)
+
+import Data.Text (Text)
+import qualified Data.Text.IO as TIO
+
+import Data.Void (Void)
+
+import Text.Megaparsec
+import Text.Megaparsec.Char
+import qualified Text.Megaparsec.Char.Lexer as L
+import qualified Control.Applicative as CA
+
+main :: IO ()
+main = do 
+        text <- TIO.readFile "data/advent08-small.txt"
+        let treeSpec = successfulParse text
+        let (tree, _) = parseTree treeSpec
+        -- print $ foldMap sum tree
+        print $ part1 tree
+        print $ part2 tree
+
+part1 = sum . fmap sum
+
+part2 = valueOfTree
+
+
+parseTree (c:m:spec) = (Node metadata children, remainder')
+    where (children, remainder) = parseManyTree c spec
+          metadata = take m remainder
+          remainder' = drop m remainder
+
+parseManyTree n spec 
+    | n == 0 = ([], spec)
+    | otherwise = ((tree:otherTrees), remainder')
+    where (tree, remainder) = parseTree spec
+          (otherTrees, remainder') = parseManyTree (n-1) remainder
+
+valueOfTree (Node metadata trees) 
+    | null trees = sum metadata
+    | otherwise = sum selectedValues
+    where childValues = map valueOfTree trees
+          selectedValues = map (\v -> childValues!!(v-1)) $ filter (<= (length trees)) metadata
+
+
+-- Parse the input file
+
+type Parser = Parsec Void Text
+
+sc :: Parser ()
+sc = L.space (skipSome spaceChar) CA.empty CA.empty
+-- sc = L.space (skipSome (char ' ')) CA.empty CA.empty
+
+lexeme  = L.lexeme sc
+integer = lexeme L.decimal
+
+treeFileP = many integer
+
+successfulParse :: Text -> [Int]
+successfulParse input = 
+        case parse treeFileP "input" input of
+                Left  _error -> [] -- TIO.putStr $ T.pack $ parseErrorPretty err
+                Right treeSpec -> treeSpec
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