Talk:Euler problems/1 to 10

(Difference between revisions)

Should the "solution" of problem 10 not contain a way how the primes are constructed? In itself its no solution. hk

• It's in problem 3 earlier on the page. The primes function is needed for the solution of many problems. Quale 16:55, 26 February 2008 (UTC)
It's barely a solution anyway, IMHO. They've changed the problems to all primes below *two* million now, and it takes about 3 minutes to run for me (Athlon64 3200+). Exscape 18:29, 27 May 2008 (UTC)

The solution for problem 7 has an off-by-one error, no? Doesn't (!!) start indexing at 0?

The solution for problem 8 is not generic and requires check the last digits. Below shows the problem and suggested correction for groupsOf.

```groupsOf _ [] = []
groupsOf n xs =
take n xs : groupsOf n ( tail xs )

groupsOf' n xs
| length group < n = []
| otherwise        = group : groupsOf' n ( tail xs )
where group = take n xs

digits = [1,1,1,1,1,0,9,9,9,9]

max5 = maximum \$ map product \$ groupsOf 5 digits   -- 6561 (wrong)
max5' = maximum \$ map product \$ groupsOf' 5 digits --  1 (correct)```
Why not use
tails
and pattern matching like below?
`maximum [product xs | xs@[_,_,_,_,_] <- map (take 5) (tails digits)]`
-- RayNbow 22:08, 24 January 2010 (UTC)
Or just take and tails:
`maximum [product . take 5 \$ d | d <- take 995 \$ tails digits]`
--Gorlum0 17:00, 25 February 2011 (UTC)

The removed Euler #3 code doesn't work e.g. for 875. -- WillNess (talk) 20:31, 16 August 2014 (UTC)