solve 2022 day 6 pt 1 & 2

2022/README.md

@@ -3,7 +3,7 @@
 |  S  |  M  |  T  |  W  |  T  |  F  |  S   |
 | :-: | :-: | :-: | :-: | :-: | :-: | :--: |
 |     |     |     |     | [1] | [2] |  [3] |
-| [4] | [5] |  6  |  7  |  8  |  9  |  10  |
+| [4] | [5] | [6] |  7  |  8  |  9  |  10  |
 | 11  | 12  | 13  | 14  | 15  | 16  |  17  |
 | 18  | 19  | 20  | 21  | 22  | 23  |  24  |
 | 24  |     |     |     |     |     |      |
@@ -13,3 +13,4 @@
 [3]: ./src/Aoc/Day3.hs
 [4]: ./src/Aoc/Day4.hs
 [5]: ./src/Aoc/Day5.hs
+[6]: ./src/Aoc/Day6.hs

2022/aoc.cabal

@@ -31,6 +31,7 @@ library
       Aoc.Day3
       Aoc.Day4
       Aoc.Day5
+      Aoc.Day6
   other-modules:
       Paths_aoc
   hs-source-dirs:

2022/app/Main.hs

@@ -7,6 +7,7 @@ import qualified Aoc.Day2
 import qualified Aoc.Day3
 import qualified Aoc.Day4
 import qualified Aoc.Day5
+import qualified Aoc.Day6
 
 main :: IO ()
 main = do
@@ -21,6 +22,7 @@ main = do
                       3 -> Aoc.Day3.solve
                       4 -> Aoc.Day4.solve
                       5 -> Aoc.Day5.solve
+                      6 -> Aoc.Day6.solve
                       _ -> error "unknown day"
 
   putStrLn $ f part contents

2022/src/Aoc/Day6.hs

@@ -0,0 +1,18 @@
+module Aoc.Day6 (solve) where
+
+import Data.List (nub, tails)
+
+-- https://stackoverflow.com/questions/27726739/implementing-an-efficient-sliding-window-algorithm-in-haskell#comment43882101_27733778
+windows :: Int -> [a] -> [[a]]
+windows n = foldr (zipWith (:)) (repeat []) . take n . tails
+
+sequenceOffset :: Eq a => Int -> [a] -> Int
+sequenceOffset len xs = len + (length $ takeWhile dupes $ windows len xs)
+  where
+    dupes ys = length ys > (length $ nub ys)
+
+solve :: Integer -> String -> String
+solve 1 input = show $ sequenceOffset 4 input
+solve 2 input = show $ sequenceOffset 14 input
+
+solve _ _ = "?"

README.md

@@ -13,7 +13,7 @@
 1. 2019
 1. [2020] **17/50** 🌟
 1. [2021] **43/50** 🌟
-1. [2022] **10/50** 🌟
+1. [2022] **12/50** 🌟
 
 [2015]: ./2015
 [2017]: ./2017