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Colorful numbers: Difference between revisions
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<pre>[0,1,2,3,4,5,6,7,8,9,10,23,24,25,26,27,28,29,32,34,35,36,37,38,39,42,43,45,46,47,48,49,52,53,54,56,57,58,59,62,63,64,65,67,68,69,72,73,74,75,76,78,79,82,83,84,85,86,87,89,92,93,94,95,96,97,98](solution1)
98765432(solution2)</pre>
=={{header|Haskell (alternate version)}}==
<lang haskell>import Data.List (inits, nub, tails, unfoldr)
-- Non-empty subsequences containing only consecutive elements from the
-- argument. For example:
--
-- consecs [1,2,3] => [[1],[1,2],[1,2,3],[2],[2,3],[3]]
consecs :: [a] -> [[a]]
consecs = drop 1 . ([] :) . concatMap (drop 1 . inits) . tails
-- The list of digits in the argument, from least to most significant. The
-- number 0 is represented by the empty list.
toDigits :: Int -> [Int]
toDigits = unfoldr step
where step 0 = Nothing
step n = let (q, r) = n `quotRem` 10 in Just (r, q)
-- True if and only if all the argument's elements are distinct.
allDistinct :: [Int] -> Bool
allDistinct ns = length ns == length (nub ns)
-- True if and only if the argument is a colorful number.
isColorful :: Int -> Bool
isColorful = allDistinct . map product . consecs . toDigits
main :: IO ()
main = do
let smalls = filter isColorful [0..99]
putStrLn $ "Small colorful numbers: " ++ show smalls
let start = 98765432
largest = head $ dropWhile (not . isColorful) [start, start-1 ..]
putStrLn $ "Largest colorful number: " ++ show largest</lang>
{{out}}
<pre>
$ colorful
Small colorful numbers: [0,1,2,3,4,5,6,7,8,9,23,24,25,26,27,28,29,32,34,35,36,37,38,39,42,43,45,46,47,48,49,52,53,54,56,57,58,59,62,63,64,65,67,68,69,72,73,74,75,76,78,79,82,83,84,85,86,87,89,92,93,94,95,96,97,98]
Largest colorful number: 98746253
</pre>
=={{header|J}}==
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