# Talk:Euler problems/121 to 130

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CaleGibbard (Talk | contribs) |
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Just another thought: as you have solutions handy for most problems, couldn't those guarding these pages do the copyvio checking themselves? |
Just another thought: as you have solutions handy for most problems, couldn't those guarding these pages do the copyvio checking themselves? |
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[[User: hk|hk]] |
[[User: hk|hk]] |
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+ | If it was posted by glguy, I'm willing to bet he's okay with it being here, but I'll check with him. |
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+ | [[User:CaleGibbard|CaleGibbard]] 14:57, 25 February 2008 (UTC) |

## Revision as of 14:57, 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? As far as I'm concerned it is. Just another thought: as you have solutions handy for most problems, couldn't those guarding these pages do the copyvio checking themselves? hk

If it was posted by glguy, I'm willing to bet he's okay with it being here, but I'll check with him. CaleGibbard 14:57, 25 February 2008 (UTC)