Talk:Euler problems/121 to 130
Jump to navigation
Jump to search
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.
On the Project Euler Forum I found the following solution for Problem 127, posted there by glguy. main = print $ solve 99999
rad x = fromIntegral $ product $ map fst $ primePowerFactors $ fromIntegral x
solve :: Int -> Int solve n = sum [ c | (rc,c) <- invrads
, 2 * rc < c
, (ra, a) <- takeWhile (\(a,_)->(c > 2*rc*a)) invrads
, a < c `div` 2
, gcd ra rc == 1
, ra * rads ! (c - a) < c `div` rc]
where
rads :: UArray Int Int
rads = listArray (1,n) $ map rad [1..n]
invrads = sort $ map (\(a,b) -> (b, a)) $ assocs rads
Would responsible people be so kind as to check copyvio for this one? hk