summaryrefslogtreecommitdiff
path: root/H35.hs
diff options
context:
space:
mode:
authorJoe Zhao <ztuowen@gmail.com>2015-03-31 23:41:55 +0800
committerJoe Zhao <ztuowen@gmail.com>2015-03-31 23:41:55 +0800
commita9abc1da41b56edbed00081800382e854d6698d0 (patch)
tree5265cc1c5296768438b67299afd59bcc57c58f0c /H35.hs
parent378f6303e8860b7bbca7dea787d584a6728cebf1 (diff)
downloadh99-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.hs21
1 files changed, 21 insertions, 0 deletions
diff --git a/H35.hs b/H35.hs
new file mode 100644
index 0000000..1d96e4e
--- /dev/null
+++ b/H35.hs
@@ -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