Determine if a string has all unique characters: Difference between revisions

import Numeric (showHex)

import Data.Char (ord)

 

duplicatedCharIndices :: String -> Maybe (Char, [Int])

((1 <) . length)

(foldl' --'

M.empty

(zip [0 ..] xs))))

Nothing

(foldl' --'

M.empty

(zip [0 ..] xs))

| otherwise = Just (c, ys)

 

main :: IO ()

main =

fTable

"First duplicated character, if any:"

(maybe

"None"

unwords

[ show c

, intercalate ", " (show <$> ixs)

]))

["", ".", "abcABC", "XYZ ZYX", "1234567890ABCDEFGHIJKLMN0PQRSTUVWXYZ"]

 

fTable :: String -> (a -> String) -> (b -> String) -> (a -> b) -> [a] -> String

fTable s xShow fxShow f xs =

unlines $

where

w = maximum (length . xShow <$> xs)</lang>

{{Out}}