Primes which contain only one odd digit: Difference between revisions
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There are 2,560 primes under 1,000,000 which contain only one odd digit. |
There are 2,560 primes under 1,000,000 which contain only one odd digit. |
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</pre> |
</pre> |
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=={{header|Haskell}}== |
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<lang haskell>import Data.List (intercalate, maximum, transpose) |
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import Data.List.Split (chunksOf) |
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import Data.Numbers.Primes (primes) |
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import Text.Printf (printf) |
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------------------ ONE ODD DECIMAL DIGIT ----------------- |
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singleOddDecimalDigit :: Int -> Bool |
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singleOddDecimalDigit = |
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(1 ==) . length . filter odd . digits |
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digits :: Int -> [Int] |
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digits = fmap (read . return) . show |
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--------------------------- TEST ------------------------- |
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main :: IO () |
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main = do |
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putStrLn "Below 1000:" |
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(putStrLn . table " " . chunksOf 10 . fmap show) $ |
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sampleBelow 1000 |
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putStrLn "Count of matches below 10E6:" |
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(print . length) $ |
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sampleBelow 1000000 |
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sampleBelow :: Int -> [Int] |
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sampleBelow = |
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filter singleOddDecimalDigit |
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. flip takeWhile primes |
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. (>) |
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------------------------- DISPLAY ------------------------ |
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table :: String -> [[String]] -> String |
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table gap rows = |
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let ws = maximum . fmap length <$> transpose rows |
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pw = printf . flip intercalate ["%", "s"] . show |
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in unlines $ intercalate gap . zipWith pw ws <$> rows</lang> |
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{{Out}} |
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<pre>Below 1000: |
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3 5 7 23 29 41 43 47 61 67 |
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83 89 223 227 229 241 263 269 281 283 |
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401 409 421 443 449 461 463 467 487 601 |
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607 641 643 647 661 683 809 821 823 827 |
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829 863 881 883 887 |
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Count of matches below 10E6: |
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2560</pre> |
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=={{header|Julia}}== |
=={{header|Julia}}== |
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