add initial solution for day09

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/Utils.hs b/lib/Utils.hs
index 4319714..89b1bd3 100644
--- a/lib/Utils.hs
+++ b/lib/Utils.hs
@@ -5,11 +5,13 @@ module Utils ( binaryToInt
              , bet
              , (&+)
              , howMany
+             , sublists
              ) where 
 
 import Data.Char (digitToInt)
 import Control.Monad
 import Data.Either
+import Data.List (inits, tails)
 
 
 binaryToInt :: String -> Int
@@ -34,3 +36,6 @@ bet k (l, u) = k >= l && k <= u
 
 howMany :: (a -> Bool) -> [a] -> Int
 howMany predicate = length . filter predicate
+
+sublists :: [a] -> [[a]]
+sublists = concatMap inits . tails