# Talk:Euler problems/121 to 130

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< Talk:Euler problems(Difference between revisions)

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− | On the Project Euler Forum I found the following solution for Problem 127, posted there by glguy. | + | On the Project Euler Forum I found the following solution for Problem 127, posted there by glguy.<BR> |

main = print $ solve 99999 | main = print $ solve 99999 | ||

## Revision as of 14:33, 25 February 2008

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