Data commit

Task/Gapful-numbers/Haskell/gapful-numbers-1.hs

@@ -0,0 +1,14 @@
+{-# LANGUAGE NumericUnderscores #-}
+
+gapful :: Int -> Bool
+gapful n = n `rem` firstLastDigit == 0
+ where
+  firstLastDigit = read [head asDigits, last asDigits]
+  asDigits = show n
+
+main :: IO ()
+main = do
+  putStrLn $ "\nFirst 30 Gapful numbers >= 100 :\n"  ++ r 30 [100,101..]
+  putStrLn $ "\nFirst 15 Gapful numbers >= 1,000,000 :\n" ++ r 15 [1_000_000,1_000_001..]
+  putStrLn $ "\nFirst 10 Gapful numbers >= 1,000,000,000 :\n" ++ r 10 [1_000_000_000,1_000_000_001..]
+ where r n = show . take n . filter gapful

Task/Gapful-numbers/Haskell/gapful-numbers-2.hs

@@ -0,0 +1,33 @@
+import Data.List (intercalate)
+import Data.List.Split (chunksOf)
+
+---------------------- GAPFUL NUMBERS --------------------
+
+isGapful :: Int -> Bool
+isGapful =
+  (0 ==)
+    . (<*>)
+      rem
+      (read . (<*>) [head, last] . pure . show)
+
+--------------------------- TEST -------------------------
+main :: IO ()
+main =
+  mapM_
+    (putStrLn . showSample)
+    [ "First 30 gapful numbers >= 100",
+      "First 15 Gapful numbers >= 1000000",
+      "First 10 Gapful numbers >= 1000000000"
+    ]
+
+showSample :: String -> String
+showSample k =
+  let ws = words k
+   in k <> ":\n\n"
+        <> unlines
+          ( fmap (intercalate ", " . fmap show) $
+              chunksOf 5 $
+                take
+                  (read (ws !! 1))
+                  [read (ws !! 5) :: Int ..]
+          )