Data commit

Task/Longest-common-substring/Haskell/longest-common-substring-1.hs

@@ -0,0 +1,16 @@
+import Data.Ord (comparing)
+import Data.List (maximumBy, intersect)
+
+subStrings :: [a] -> [[a]]
+subStrings s =
+  let intChars = length s
+  in [ take n $ drop i s
+     | i <- [0 .. intChars - 1]
+     , n <- [1 .. intChars - i] ]
+
+longestCommon :: Eq a => [a] -> [a] -> [a]
+longestCommon a b =
+  maximumBy (comparing length) (subStrings a `intersect` subStrings b)
+
+main :: IO ()
+main = putStrLn $ longestCommon "testing123testing" "thisisatest"

Task/Longest-common-substring/Haskell/longest-common-substring-2.hs

@@ -0,0 +1,18 @@
+import Control.Monad ((<=<))
+import Data.List (inits, intersect, maximumBy, tails)
+import Data.Ord (comparing)
+
+----------------- LONGEST COMMON SUBSTRING ---------------
+
+longestCommon :: Eq a => [a] -> [a] -> [a]
+longestCommon a b =
+  let pair [x, y] = (x, y)
+   in maximumBy (comparing length) $
+        (uncurry intersect . pair) $
+          [tail . inits <=< tails] <*> [a, b]
+
+--------------------------- TEST -------------------------
+main :: IO ()
+main =
+  putStrLn $
+    longestCommon "testing123testing" "thisisatest"