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    1 {-|
    2 Module:      Y2015.D10
    3 Description: Advent of Code Day 10 Solutions.
    4 License:     MIT
    5 Maintainer:  @tylerjl
    6 
    7 Solutions to the day 10 set of problems for <adventofcode.com>.
    8 -}
    9 module Y2015.D10
   10   ( lookSay
   11   ) where
   12 
   13 import Data.List (group)
   14 
   15 -- |Play the "looksay" game
   16 lookSay
   17   :: String -- ^ List of initial numbers
   18   -> Int -- ^ Iterations
   19   -> String -- ^ Resulting looksay game string
   20 lookSay = (!!) . iterate (concatMap walk . group)
   21   where
   22     walk s@(h:_) = show (length s) ++ [h]
   23     walk _ = "0"