Euler Problems
kinuthiA muchanE
muchanek at gmail.com
Sun Jul 13 05:31:30 BST 2008
Andrew,
I tried doing it manually and I can assure you it was not pretty, there
are just too many places you can go wrong...or you could be lucky, you
never know :-/. I am trying number 80 it is too easy, but apparently I
can not get my decimals right!:-(
Kinuthia...
On Sat, 2008-07-12 at 19:16 -0400, Andrew Mathenge wrote:
> I switched to C/C++ when I realised that perl was going to make me
> grey before anything came out.
>
> I might do what you did with #18 but right now I have a pad full of
> numbers, notes, lines and many other scribbles. I'm looking for some
> sort of logic. If I don't have an "eureka" moment, then I'll create
> that multi-dimensional array and brute force my way through it.
>
> Alternatively, I can do it manually, but that will make me feel less of a man.
>
> Andrew.
>
> On Sat, Jul 12, 2008 at 4:53 PM, kinuthiA muchanE <muchanek at gmail.com> wrote:
> > Habari,
> > ... and what language are you using Mathenge? Perl? #18 proved to be too
> > demanding for me, actually I skipped it all together with #15, I only
> > solved them yesterday!! The best way, IMHO, to solve #18 is to have a
> > multi-dimensional array, or in Python a list of lists, and then realise
> > that you are either at the end or at the beginning of the array...Oh
> > my... that sounds obscure!
> > :-/
> > Kinuthia...
> > On Sat, 2008-07-12 at 15:13 -0400, Andrew Mathenge wrote:
> >> Until you posed question #26 I didn't even know project euler existed
> >> Bwana Kinuthia, but I'm trying my best.
> >>
> >> Right now #18 is killing me trying to solve it without brute force.
> >> And I agree. Zacharia did a great job with #12. Mine took forever.
> >>
> >> Zacharia, sign up.
> >>
> >> The dance continues....
> >>
> >> On Sat, Jul 12, 2008 at 1:15 PM, kinuthiA muchanE <muchanek at gmail.com> wrote:
> >> > Habari wote,
> >> >
> >> > Now, this is getting lively, and I think Zacharia is the teacher all of
> >> > us have been longing for :-) Step by step, you elucidate all the
> >> > underling principles. I thought nobody ever reads this, I am mistaken.
> >> > Zacharia, why dont you subscribe to project Euler
> >> > (http://projecteuler.net ) and at least I will not be leading in the
> >> > list Kenyans who have solved the most problems, only 52, the last time I
> >> > looked.
> >> > And to Andrew (ha... you are at 17 ), you ask a question and then
> >> > disappear!! Hmmmm, and where is Miano??
> >> >
> >> > Cheers!!
> >> > Kinuthia...
> >> >
> >> >
> >> >
> >> > On Sat, 2008-07-12 at 07:16 -0700, Zacharia M. Rugongo wrote:
> >> >> This email is from a ubuntu-ke subscriber to other subscribers inluding you:)
> >> >> My solution to Euler #12 runs in less than 1 minute.
> >> >>
> >> >>
> >> >> Let us list the factors of the first eight triangle numbers:
> >> >> 1: 1
> >> >> 3: 1,3
> >> >> 6: 1,2,3,6
> >> >> 10: 1,2,5,10
> >> >> 15: 1,3,5,15
> >> >> 21: 1,3,7,21
> >> >> 28: 1,2,4,7,14,28
> >> >> 36: 1,2,3,4,6,8,9,12,18,36
> >> >> Note the numbers that are underlined in each sequence. This is the half way point.
> >> >> a) If you divide the triangle number by the first number that is underlined the result will be greater than the divisor.
> >> >> b)
> >> >> On the other hand if you divide the triangle number by the second
> >> >> number that is underlined the result will be less than the divisor.
> >> >> c)
> >> >> The triangle number 36 has only one number at the centre of the
> >> >> sequence, because that centre number is the square root of the triangle
> >> >> number 36.
> >> >>
> >> >> In
> >> >> cases a) and b) if you wanted to know the total number of divisors, you
> >> >> look for the position of the number underlined as described in b), then
> >> >> subtract 1 from it, then multiply it by 2. For example, for triangle
> >> >> number 28, value 7 is in position 4. So (4-1) * 2 = 6
> >> >>
> >> >> In
> >> >> cases c) if you wanted to know the total number of divisors, you look
> >> >> for the position of the center number underlined, then multiply it by
> >> >> 2. For example, for triangle number 36, value 6 is in position 5.
> >> >> So 5 * 2 = 10
> >> >>
> >> >> Here is the program.
> >> >>
> >> >>
> >> >> Dim triagNo As Integer ' Triangle number
> >> >> Dim counter As Integer ' for calculating the next triangle number
> >> >> Dim varValue As Integer ' Incremented in search for a Divisor
> >> >> Dim NoDivisors As Integer ' number of Divisors found
> >> >> Dim Divisor As Integer ' Value of found Divisor
> >> >>
> >> >> Do
> >> >> counter += 1
> >> >> triagNo = triagNo + counter
> >> >> varValue = 0
> >> >> Divisor = 0
> >> >> NoDivisors = 0
> >> >>
> >> >> Do
> >> >> varValue += 1
> >> >> If triagNo Mod varValue = 0 Then ' is varValue a Divisor
> >> >> Divisor = varValue
> >> >> NoDivisors += 1
> >> >> End If
> >> >> Loop Until (triagNo / Divisor) <= Divisor ' Find when you reach the second centre value
> >> >>
> >> >> If (triagNo / Divisor) = Divisor Then
> >> >> NoDivisors = (NoDivisors - 1) * 2 + 1 ' cases a) and b)
> >> >> Else
> >> >> NoDivisors = (NoDivisors - 1) * 2 ' case c)
> >> >> End If
> >> >>
> >> >> Loop Until (NoDivisors > 500)
> >> >>
> >> >> TextBox1.Text = triagNo
> >> >>
> >> >>
> >> >> Z. Mwangi
> >> >>
> >> >>
> >> >>
> >> >> ----- Original Message ----
> >> >> From: Andrew Mathenge <mathenge at gmail.com>
> >> >> To: ubuntu Kenya <ubuntu-ke at lists.ubuntu.com>
> >> >> Sent: Friday, July 11, 2008 3:24:23 AM
> >> >> Subject: Re: Euler Problems
> >> >>
> >> >> This email is from a ubuntu-ke subscriber to other subscribers inluding you:)
> >> >> I've been working on #12 and the performance is simply not acceptable.
> >> >> Has anyone been able to get this running as fast as some of the posts
> >> >> on the site claim?
> >> >>
> >> >> Andrew.
> >> >>
> >> >> On Tue, Jul 8, 2008 at 12:40 PM, kinuthiA muchanE <muchanek at gmail.com> wrote:
> >> >> > Andrew,
> >> >> > For #10, if you do not use a sieve to find the primes, it will run
> >> >> > forever!
> >> >> > There is one called the Sieve of Erastothenes. Check it out on
> >> >> > Wikipedia.
> >> >> >
> >> >> > Good luck :-)
> >> >> > Kinuthia...
> >> >> > On Tue, 2008-07-08 at 10:47 -0400, Andrew Mathenge wrote:
> >> >> >> I'm still trying them. I started at #1 after the one you proposed
> >> >> >> (#26) and I'm at #10 now. This one should be very simple but I don't
> >> >> >> know why it's taking so long to run.
> >> >> >>
> >> >> >> Andrew.
> >> >> >>
> >> >> >> On Tue, Jul 8, 2008 at 6:52 AM, kinuthiA muchanE <muchanek at gmail.com> wrote:
> >> >> >> > Habari,
> >> >> >> > Anybody still trying these problems, you are all so, so silent...
> >> >> >> >
> >> >> >> > Kinuthia...
> >> >> >> >
> >> >> >> >
> >> >> >
> >> >> >
> >> >>
> >> >> --
> >> >> Ubuntu-ke mailing list
> >> >> Ubuntu-ke at lists.ubuntu.com
> >> >> https://lists.ubuntu.com/mailman/listinfo/ubuntu-ke
> >> >>
> >> >>
> >> >>
> >> >>
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> >> >
> >
> >
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