|
import Data.List (find)
|
|
|
|
isqrt :: (Integral n) => n -> n
|
|
isqrt = floor . sqrt . fromIntegral
|
|
|
|
primeFactors :: (Integral n) => n -> [n]
|
|
primeFactors n =
|
|
case find ((== 0) . (n `mod`)) [2 .. isqrt n] of
|
|
Nothing -> [n]
|
|
Just m -> m : primeFactors (n `div` m)
|