From 6b16d921543a62d880171791d39bcc58560785fa Mon Sep 17 00:00:00 2001 From: Charles Date: Sun, 11 Aug 2019 22:36:40 +0200 Subject: haskell problems 001 -> 006 --- haskell/003-largest_prime_factor.hs | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) create mode 100644 haskell/003-largest_prime_factor.hs (limited to 'haskell/003-largest_prime_factor.hs') diff --git a/haskell/003-largest_prime_factor.hs b/haskell/003-largest_prime_factor.hs new file mode 100644 index 0000000..4150377 --- /dev/null +++ b/haskell/003-largest_prime_factor.hs @@ -0,0 +1,19 @@ +-- Largest prime factor + +-- Problem 3 +-- The prime factors of 13195 are 5, 7, 13 and 29. + +-- What is the largest prime factor of the number 600851475143 ? + + +main = do + print (last $ factors 600851475143) + +factors x = trial_division 2 x + +trial_division :: Int -> Int -> [Int] +trial_division by x + | x <= 1 = [] + | x `mod` by == 0 = by:trial_division by (x `div` by) + | otherwise = trial_division (by + 1) x + -- cgit