Commit: 992a0cac61c9c7ab1cea01d683cc526b66a72e8a
Parent: 36dd1e38f2ba7590338c09833225b38808295653
Author: Randy Palamar
Date: Sat, 2 Dec 2023 13:28:47 -0700
day 2
The task wasn't too challenging today but I'm still having
troubles with Haskell. First I don't fully understand the rules
around function composition such as when are you allowed to use
`.` vs `$`. Second there seems to be some annoying restrictions on
return types, for instance it seems that returning a list of lists
of tuples is not valid but returning a tuple of lists of tuples
is.
Again this was too fast to get repeatable performance numbers.
Even more so than yesterday. Execution time was on the order of
150us.
Diffstat:
| A | day2/day2.hs | | | 68 | ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
1 file changed, 68 insertions(+), 0 deletions(-)
diff --git a/day2/day2.hs b/day2/day2.hs
@@ -0,0 +1,68 @@
+-- AOC 2023: Day 2
+--
+-- There is a game where you want to determine the number of each
+-- colour of cube in bag. The bag contains red, green, and blue
+-- cubes.
+--
+-- Task 1: Grab a random handful of cubes and count each colour.
+-- Do this a few times per game and perform many games. This will
+-- result in a list of data such as:
+--
+-- Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+-- ...
+-- Game N: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green
+--
+-- After this data was collected you are told that the bag
+-- contained only 12 red, 13 green, and 14 blue cubes. Provide
+-- the sum of all the valid game's numbers.
+--
+-- Task 2: The power of a set of cubes is the minimum number of
+-- each colour needed to make a game valid. Provide the sum of
+-- the powers of all games.
+--
+import qualified Data.Text as T
+import qualified Data.Text.IO as TI
+import Text.Printf (printf)
+
+splitgame :: T.Text -> (Int, [(Int, T.Text)])
+splitgame st =
+ let (gn, t) = T.breakOn (T.pack ": ") st
+ n = read $ T.unpack $ snd $ T.break (== ' ') gn :: Int
+ tuples =
+ map to_int_text . map (T.break (== ' ')) $
+ T.splitOn (T.pack ", ") $
+ T.replace (T.pack ": ") (T.pack "") $
+ T.replace (T.pack ";") (T.pack ",") t
+ in (n, tuples)
+
+to_int_text :: (T.Text, T.Text) -> (Int, T.Text)
+to_int_text (f, s) = (read (T.unpack f) :: Int, s)
+
+get_colour_list :: T.Text -> [(Int, T.Text)] -> [Int]
+get_colour_list c l = map fst $ filter ((== c) . snd) l
+
+get_rgb_triple :: [(Int, T.Text)] -> ([Int], [Int], [Int])
+get_rgb_triple l =
+ let r = get_colour_list (T.pack " red") l
+ g = get_colour_list (T.pack " green") l
+ b = get_colour_list (T.pack " blue") l
+ in (r, g, b)
+
+isvalidgame :: (Int, [(Int, T.Text)]) -> Int
+isvalidgame (n, t) =
+ let (r, g, b) = get_rgb_triple t
+ in if (null $ filter (> 12) r) &&
+ (null $ filter (> 13) g) && (null $ filter (> 14) b)
+ then n
+ else 0
+
+gamepower :: (Int, [(Int, T.Text)]) -> Int
+gamepower (_, t) =
+ let (r, g, b) = get_rgb_triple t
+ in (foldr1 max r) * (foldr1 max g) * (foldr1 max b)
+
+main = do
+ contents <- TI.getContents
+ let games = map splitgame $ T.lines contents
+ printf "Task 1: %8d\n" (sum $ map isvalidgame games)
+ printf "Task 2: %8d\n" (sum $ map gamepower games)