Day 22, with stack build system

[advent-of-code-16.git] / adventofcode16 / app / advent09.hs

diff --git a/adventofcode16/app/advent09.hs b/adventofcode16/app/advent09.hs
new file mode 100644 (file)
index 0000000..a3ce495
--- /dev/null
+++ b/adventofcode16/app/advent09.hs
@@ -0,0 +1,57 @@
+module Main(main) where
+
+import Data.List.Split (splitOn)
+import Data.Char (isSpace)
+
+type Chunk = (Int, String)
+
+main :: IO ()
+main = do 
+        textL <- readFile "data/advent09.txt" 
+        let text = filter (not . isSpace) textL
+        part1 text
+        part2 text
+
+part1 :: String -> IO ()
+part1 text = do 
+    print $ cLength $ decompress text
+
+part2 :: String -> IO ()
+part2 text = do 
+    print $ cLength $ decompress2 text
+
+
+decompress :: String -> [Chunk]
+decompress text = 
+    if not (null msuf) 
+        then (1, pre):(num, chunk):drest
+        else [(1, pre)]
+    where 
+        (pre, msuf) = span ('(' /= ) text
+        (marker, suf) = span (')' /= ) msuf
+        ln = splitOn "x" (tail marker)
+        len = read (ln!!0) :: Int
+        num = read (ln!!1) :: Int
+        (chunk, remainder) = splitAt len (tail suf)
+        drest = decompress remainder
+
+decompress2 :: String -> [Chunk]
+decompress2 text = 
+    if not (null msuf) 
+        then [(1, pre)] ++ mulDchunks ++ drest
+        else [(1, pre)]
+    where 
+        (pre, msuf) = span ('(' /= ) text
+        (marker, suf) = span (')' /= ) msuf
+        ln = splitOn "x" (tail marker)
+        len = read (ln!!0) :: Int
+        num = read (ln!!1) :: Int
+        (chunk, remainder) = splitAt len (tail suf)
+        dchunks = decompress2 chunk
+        mulDchunks = [(dl * num, ds) | (dl, ds) <- dchunks]
+        drest = decompress2 remainder
+
+cLength :: [Chunk] -> Int
+cLength = sum . map (clen)
+    where clen (n, t) = n * (length t)
+