Solve Project Euler 20

src/projectEuler/question20.hs

@@ -0,0 +1,18 @@
+{-
+n! means n x (n - 1) x ... x 3 x 2 x 1.
+For example, 10! = 10 x 9 x ... x 3 x 2 x 1 = 3628800,
+  and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
+Find the sum of the digits in the number 100!.
+-}
+
+import           Data.Char (digitToInt)
+
+read' :: Integer -> String
+read' = show
+
+main :: IO ()
+main = do
+  print $ "Answer: " <> show ans
+
+ans :: Int
+ans = sum $ map digitToInt $ read' $ product [1..100]