diff options
Diffstat (limited to '2021/Util.hs')
-rw-r--r-- | 2021/Util.hs | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/2021/Util.hs b/2021/Util.hs new file mode 100644 index 0000000..7cd674d --- /dev/null +++ b/2021/Util.hs @@ -0,0 +1,14 @@ +module Util where + +import Data.List +import Data.List.NonEmpty (NonEmpty(..), (<|)) + + +splitOn :: (a -> Bool) -> [a] -> NonEmpty [a] +splitOn _ [] = [] :| [] +splitOn f (x:xs) | f x = [] <| splitOn f xs + | otherwise = let l :| ls = splitOn f xs + in (x : l) :| ls + +splits' :: [a] -> [(a, [a])] +splits' l = zip l (zipWith (++) (inits l) (tail (tails l))) |