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authorJoe Zhao <ztuowen@gmail.com>2015-03-31 23:41:55 +0800
committerJoe Zhao <ztuowen@gmail.com>2015-03-31 23:41:55 +0800
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rename to H**, +31 +32 +33 +34 +35 +36
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+import System.Random
+
+isPrime :: Integral a => a -> Bool
+isPrime x = and $ fmap ((/=0).(mod x)) [2..(x-1)]
+
+testn = 10
+
+isPrimeT 2 = True
+isPrimeT x = and $ fmap ((/=0).(fstPow x (x-1))) $ take testn $ randomRs (2,(x-1)) (mkStdGen 100)
+
+fstPow _ 1 x = x
+fstPow m y x
+ | y `mod` 2 == 1 = (x * (fstPow m (y `div` 2) (sqr x))) `mod` m
+ | otherwise = fstPow m (y `div` 2) (sqr x)
+ where sqr a = (a*a) `mod` m