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author | Joe Zhao <ztuowen@gmail.com> | 2015-03-31 23:41:55 +0800 |
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committer | Joe Zhao <ztuowen@gmail.com> | 2015-03-31 23:41:55 +0800 |
commit | a9abc1da41b56edbed00081800382e854d6698d0 (patch) | |
tree | 5265cc1c5296768438b67299afd59bcc57c58f0c /H35.hs | |
parent | 378f6303e8860b7bbca7dea787d584a6728cebf1 (diff) | |
download | h99-a9abc1da41b56edbed00081800382e854d6698d0.tar.gz h99-a9abc1da41b56edbed00081800382e854d6698d0.tar.bz2 h99-a9abc1da41b56edbed00081800382e854d6698d0.zip |
rename to H**, +31 +32 +33 +34 +35 +36
Diffstat (limited to 'H35.hs')
-rw-r--r-- | H35.hs | 21 |
1 files changed, 21 insertions, 0 deletions
@@ -0,0 +1,21 @@ +module H35 +( primeFactors +) where + +primeSift (x:xs) = (x:) $ primeSift $ filter ((/=0).(`mod` x)) xs + +primes = primeSift [2..] + +primeFactors x = pF x primes + where + pF a xxs@(x:xs) + | a == 1 = [] + | a `mod` x == 0 = x:(pF (div a x) xxs) + | otherwise = pF a xs + +factor :: Integer -> [Integer] + +factor 1 = [] +factor n = + let prime = head $ dropWhile ((/= 0) . mod n) [2 .. n] + in (prime :) $ factor $ div n prime |