Find adjacent primes which differ by a square integer: Difference between revisions
Find adjacent primes which differ by a square integer (view source)
Revision as of 20:37, 4 November 2022
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Line 536:
240 IF Q = 1 THEN P2 = P: P = T: RETURN
250 GOTO 220</syntaxhighlight>
=={{header|Haskell}}==
<syntaxhighlight lang="haskell">
import Data.List.Split ( divvy )
isSquare :: Int -> Bool
isSquare n = (snd $ properFraction $ sqrt $ fromIntegral n) == 0.0
isPrime :: Int -> Bool
isPrime n
|n == 2 = True
|n == 1 = False
|otherwise = null $ filter (\i -> mod n i == 0 ) [2 .. root]
where
root :: Int
root = floor $ sqrt $ fromIntegral n
solution :: [[Int]]
solution = filter (\li -> isSquare (last li - head li ) &&
( last li - head li ) > 36 ) $ divvy 2 1 $ filter isPrime [2..1000000]
printResultLine :: [Int] -> String
printResultLine list = show ( last list ) ++ " - " ++ ( show $ head list )
++ " = " ++ ( show ( last list - head list ))
main :: IO ( )
main = do
let resultPairs = solution
mapM_ (\li -> putStrLn $ printResultLine li ) resultPairs</syntaxhighlight>
{{out}}
<pre>
89753 - 89689 = 64
107441 - 107377 = 64
288647 - 288583 = 64
368021 - 367957 = 64
381167 - 381103 = 64
396833 - 396733 = 100
400823 - 400759 = 64
445427 - 445363 = 64
623171 - 623107 = 64
625763 - 625699 = 64
637067 - 637003 = 64
710777 - 710713 = 64
725273 - 725209 = 64
779477 - 779413 = 64
801947 - 801883 = 64
803813 - 803749 = 64
821741 - 821677 = 64
832583 - 832519 = 64
838349 - 838249 = 100
844841 - 844777 = 64
883871 - 883807 = 64
912167 - 912103 = 64
919511 - 919447 = 64
954827 - 954763 = 64
981887 - 981823 = 64
997877 - 997813 = 64
</pre>
=={{header|J}}==
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