AoC 2022 D6: Tuning Trouble

Haskell | Problem statement | Source code | Tags: Data structures

← Previous Back to AoC Index Next →

Part 1

TBH this feels more like a day 1 problem. I just need to iterate through the string, taking substrings of length 4. I use a Set to deduplicate the characters, and if we still have 4 characters, then they are all unique.

roll :: Int -> Int -> Text -> Int
roll index input
  | (length . Set.fromList . T.unpack) prefix == 4 = index + 4
  | otherwise = roll (index + 1) $ T.tail input
  where
    prefix = T.take 4 input
hs

Part 2

Same as part 1, but with length 14 instead of 4. I parameterize roll over the length of the marker.

roll :: Int -> Int -> Text -> Int
roll len index input
  | (length . S.fromList . T.unpack) prefix == len = index + len
  | otherwise = roll len (index + 1) $ T.tail input
  where
    prefix = T.take len input
hs

← Previous Back to AoC Index Next →