A place to air possible concerns or difficulties in understanding ProjectEuler problems. This forum is not meant to publish solutions. This forum is NOT meant to discuss solution methods or giving hints how a problem can be solved.
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As your posts will be visible to the general public you are requested to be thoughtful in not posting anything that might explicitly give away how to solve a particular problem.
This forum is NOT meant to discuss solution methods for a problem.
In particular don't post any code fragments or results.
Don't start begging others to give partial answers to problems
Don't ask for hints how to solve a problem
Don't start a new topic for a problem if there already exists one
Plebian wrote:Edit2: Forum thread's closed but.. wow. The other Python solutions are much more complex and shorter than mine.
I recall having had the same experience, when I first saw the first forum thread. Now, I advice to study those smarter solutions and understand how they work; that will boost your Python programming and math skills and better enable you to solve the next problem - and the next problem - and... - at least that is how it worked for me
rjashton wrote:So I managed to solve this one fairly quickly but I was wondering: if I can't post my code here where can I post it?
Do you think your code would interest any of us ?
Does it use a revolutionary formula ? (you can't even call it an algorithm for this problem)
If not, why do you want to post your code somewhere ?
Have you read the forum and the PDF ? Haven't you found the exact same solution as yours ?
Jeez, what did you get stuck where the sun don't shine?
Thanks for the warm welcome to the community.
Here's a riddle for you: what's the point in a forum where someone asking to discuss something isn't allowed to and is castigated for even asking where?
rjashton wrote:So I managed to solve this one fairly quickly but I was wondering: if I can't post my code here where can I post it?
Do you think your code would interest any of us ?
Does it use a revolutionary formula ? (you can't even call it an algorithm for this problem)
If not, why do you want to post your code somewhere ?
Have you read the forum and the PDF ? Haven't you found the exact same solution as yours ?
Jeez, what did you get stuck where the sun don't shine?
Thanks for the warm welcome to the community.
Here's a riddle for you: what's the point in a forum where someone asking to discuss something isn't allowed to and is castigated for even asking where?
Look here rjashton,
As of date this problem is solved by 161862 people.
Let's do an estimate.
Suppose one out of 20 of those people want to post their solution that would mean more than 8000 posts to wade through.
Please try to understand that we don't reserve the space for that, simply because it would mean that the same would be repeated over and over again.
War ruins the life and health of untold numbers of innocent children.
rjashton wrote:
Jeez, what did you get stuck where the sun don't shine?
Thanks for the warm welcome to the community.
Here's a riddle for you: what's the point in a forum where someone asking to discuss something isn't allowed to and is castigated for even asking where?
Let me apologize, i didn't mean to sound harsh. I'm a new user, just like you, i don't talk in the name of a "community". Don't feel uncomfortable about asking questions here just because of my post.
I have yet to understand why so many people want to post their useless code.
I wish there was a page dedicated to that, separate from the forums, so everyone would be satisfied.
Hibernatus34 wrote:
I have yet to understand why so many people want to post their useless code.
I wish there was a page dedicated to that, separate from the forums, so everyone would be satisfied.
I was wondering if there is any place at all I can discuss the solution in detail on this site?
After spending a couple hours on this problem and finding a truly elegant solution, I was dismayed to see the solutions other people had submitted, and the general state of the solutions thread. I was under the impression from the 'about' section of the site that said thread would be a place where people discussed how to find the simplest and most elegant solutions to problems. Instead it was just a repository for people posting their code, usually poorly written, without adequate commenting and with no explanation.
I'm posting this because I generalized the solution and derived a simple 2nd degree polynomial that would give (or approximate for most values) the solution at ANY point, not just 1000. I think people would be interested in seeing it and I'd be interested in discussing taking the solution a step or two further. Reading through the 38 page solution thread for this problem, I did not find a single other person who found this solution, nor anyone who came close. There were only a handful who even attempted a mathematical solution to begin with.
Did you read the PDF for this problem?
You can find it directly to the right of the green tick for this problem on the problems page.
Is your solution better than the method developed there?
Do you think the method there can be developed any further?
Do you think that there exists a better solution than the one given there?
(cross posted with TripleM)
War ruins the life and health of untold numbers of innocent children.
hk wrote:Did you read the PDF for this problem?
You can find it directly to the right of the green tick for this problem on the problems page.
Is your solution better than the method developed there?
Do you think the method there can be developed any further?
Do you think that there exists a better solution than the one given there?
(cross posted with TripleM)
Thanks for the quick response. And yes, I read the .pdf. My solution is definitely better than any iterative approach, or even the Gaussian approach as it allows for the computation of the solution directly by using a simple polynomial. The method there can be developed further by showing a repeating pattern that occurs in groupings of partial sums. Noticing this pattern allowed me to formulate the sum in terms of a single mathematical expression, which lead to the aforementioned solution.
In my opinion a solution that approximates the answer in most cases isn't a solution.
The solution in the PDF uses also a polynomial and does not approximate anything . It does not need be developed further spotting patterns. It is O(1).
(The Gaussian method is a polynomial of degree two).
Please study it thoroughly as there is no better method.
War ruins the life and health of untold numbers of innocent children.
In my opinion a solution that approximates the answer in most cases isn't a solution.
A polynomial is a continuous function, but the sum of numbers divisible by 3 or 5 is not continuous. Thus it is not exact for values which are not numbers which are divisible by 3 or 5... which are most numbers.
The solution in the PDF uses also a polynomial and does not approximate anything . It does not need be developed further spotting patterns. It is O(1).
(The Gaussian method is a polynomial of degree two).
Please study it thoroughly as there is no better method.
I actually just noticed that this approach does indeed simplify to the polynomial I derived. Still, the simplified polynomial requires less computation than the example given.
In my opinion a solution that approximates the answer in most cases isn't a solution.
A polynomial is a continuous function, but the sum of numbers divisible by 3 or 5 is not continuous. Thus it is not exact for values which are not numbers which are divisible by 3 or 5... which are most numbers.
But you are required to solve a "not continuous problem".
Many problems on Project Euler are about "not continuous problems".
Most of the time they require somewhat different solution methods than continuous ones to get the exact answer.
War ruins the life and health of untold numbers of innocent children.
I tried to resolve problem 001. "Tried" is maybe the wrong declaration, but there is some bug around which prevents me to go further.
Here again the task: "If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000."
The sample with the numbers < 10 is correct with my code. But < 1000 is not. How can I post a code, that you could kindly check it?
Here is my output for value < 15.
zähler: 0
..addiere 0 + 0 = 0
zähler: 3
..addiere 3 + 0 = 3
zähler: 6
..addiere 6 + 3 = 9
zähler: 9
..addiere 9 + 9 = 18
zähler: 12
..addiere 12 + 18 = 30
All numbers multiple by 3 < 15 = 30
zähler: 0
..addiere 0 + 0 = 0
zähler: 5
..addiere 5 + 0 = 5
zähler: 10
..addiere 10 + 5 = 15
All numbers multiple by 5 < 15 = 15
The sum of the two subsum = 45
When I do it for < 1000, then I always get a wrong result back: The number for my calculation is: 22548.
I think it is the logical or and not and, right? The problem is the duplicate 15... . If yes, then I need a bit more time again to think. about it. But the thing is, a logical or is true,when a and b are true same time.
I think it is the logical or and not and, right? The problem is the duplicate 15... . If yes, then I need a bit more time again to think. about it. But the thing is, a logical or is true,when a and b are true same time.
I will check it again.
Cheers
agrubner
Try to see if you can solve the problem by just iterating once over the relevant range of numbers. You shouldn't run into duplication errors that way and it'll help you formulate the solution by focusing on the logic.
Joined PE in May 2011
Entia non sunt multiplicanda praeter necessitatem
