Day 14.

README.md

@@ -25,7 +25,7 @@ Now located in this repository's wiki.
 | 11  | ~ 7         |
 | 12  | ~ 1.5       |
 | 13  | ~ 0.5       |
-| 14  |             |
+| 14  |  22.3       |
 | 15  |             |
 | 16  |             |
 | 17  |             |

app/Main.hs

@@ -30,4 +30,4 @@ import qualified Day24
 import qualified Day25
 
 main :: IO ()
-main = Day13.main
+main = Day14.main

src/Day14.hs

@@ -1,6 +1,34 @@
 module Day14 (main) where
 
+import Data.Char (digitToInt, intToDigit)
+import Data.List (tails, isPrefixOf)
+import Data.Sequence (Seq(..), fromList, index, (><))
+
+type Scores = Seq Int
+type Elves  = (Int, Int) -- indices of first and second elf
+
+(!) = index
+
+input = 793061
+inputList = [7, 9, 3, 0, 6, 1]
+initialScores = [3, 7]
+initialElves  = (0, 1)
+
+getScores :: [Int]
+getScores = initialScores ++ getNextScores initialElves (fromList initialScores)
+    where getNextScores (e1, e2) scores =
+            let newScores  = map digitToInt . show $ scores ! e1 + scores ! e2
+                nextScores = scores >< fromList newScores
+                nextElves  = ((e1 + scores ! e1 + 1) `mod` length nextScores, (e2 + scores ! e2 + 1) `mod` length nextScores)
+            in  newScores ++ getNextScores nextElves nextScores
+
+part1 :: String
+part1 = map intToDigit . take 10 . drop input $ getScores
+
+part2 :: Int
+part2 = length . takeWhile (not . (inputList `isPrefixOf`)) . tails $ getScores
+
 main :: IO ()
 main = do
-    input <- readFile "input/14.txt"
+    print part1
-    print input
+    print part2