Determine if a string has all unique characters: Difference between revisions
Determine if a string has all unique characters (view source)
Revision as of 12:07, 20 December 2020
, 3 years ago→{{header|Haskell}}: Simplified a groupBy expression using `on`
m (→{{header|Haskell}}: Minor tidying.) |
(→{{header|Haskell}}: Simplified a groupBy expression using `on`) |
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Line 1,299:
<lang Haskell>import Data.List (groupBy, intersperse, sort, transpose)
import Data.Char (ord, toUpper)
import Data.Function(on)
import Numeric (showHex)
hexFromChar :: Char -> String
hexFromChar c = map toUpper $ showHex (ord c) ""
string :: String -> String
string xs = ('\"' : xs)
char :: Char -> String
char c = ['\'', c, '\'']
size :: String -> String
size = show . length
positions :: (Int, Int) -> String
positions (a, b) = show a
forTable :: String -> [String]
forTable xs = string xs : go (allUnique xs)
Line 1,321 ⟶ 1,323:
go Nothing = [size xs, "yes", "", "", ""]
go (Just (u, ij)) = [size xs, "no", char u, hexFromChar u, positions ij]
showTable :: Bool -> Char -> Char -> Char -> [[String]] -> String
showTable _ _ _ _ [] = []
Line 1,329 ⟶ 1,331:
(if header
then z : hr : zs
else intersperse hr zss)
[hr]
where
vss = map (map length) contents
ms = map maximum (transpose vss) :: [Int]
hr = concatMap (\n -> sep : replicate n hor) ms
top = replicate (length hr) hor
bss = map (map (`replicate` ' ') . zipWith (-) ms) vss
zss@(z:zs) =
zipWith
(\us bs -> concat (zipWith (\x y -> (ver : x)
contents
bss
table xs =
showTable
Line 1,351 ⟶ 1,353:
(["string", "length", "all unique", "1st diff", "hex", "positions"] :
map forTable xs)
allUnique
:: (Ord b, Ord a, Num b, Enum b)
=> [a] -> Maybe (a, (b, b))
allUnique xs = go . groupBy (
where
go [] = Nothing
go ([_]:us) = go us
go (((u, i):(_, j):_):_) = Just (u, (i, j))
main :: IO ()
main =
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