Add haskell solutions for challenge 2

2 files changed, 37 insertions, 0 deletions

diff --git a/challenge-002/alexander-pankoff/haskell/ch-1.hs b/challenge-002/alexander-pankoff/haskell/ch-1.hs
new file mode 100644
index 0000000000..c8f7230d79
--- /dev/null
+++ b/challenge-002/alexander-pankoff/haskell/ch-1.hs
@@ -0,0 +1,7 @@
+module Main where
+
+main :: IO ()
+main = interact removeLeadingZeros
+
+removeLeadingZeros :: String -> String
+removeLeadingZeros = dropWhile (== '0')
diff --git a/challenge-002/alexander-pankoff/haskell/ch-2.hs b/challenge-002/alexander-pankoff/haskell/ch-2.hs
new file mode 100644
index 0000000000..f3d8b76ca6
--- /dev/null
+++ b/challenge-002/alexander-pankoff/haskell/ch-2.hs
@@ -0,0 +1,30 @@
+module Main where
+
+import Control.Monad (zipWithM)
+import Data.List (elemIndex)
+
+main :: IO ()
+main = do
+  print $ toBase35 10
+  print $ toBase35 36
+  print $ fromBase35 "A"
+  print $ fromBase35 "11"
+  print $ fromBase35 "10"
+
+base35Alphabet :: [Char]
+base35Alphabet = ['0' .. '9'] ++ ['A' .. 'Y']
+
+toBase35 :: Int -> String
+toBase35 x = go "" x
+  where
+    go acc 0 = acc
+    go acc x = go (base35Alphabet !! (x `mod` 35) : acc) (x `div` 35)
+
+fromBase35 :: [Char] -> Maybe Int
+fromBase35 =
+  fmap sum
+    . zipWithM (\i c -> (*) (35 ^ i) <$> base35DigitToInt c) [0 ..]
+    . reverse
+
+base35DigitToInt :: Char -> Maybe Int
+base35DigitToInt c = elemIndex c base35Alphabet