Menu
Search

Forums

Forum Index

Thread overview
Range handling difficulties
April 24
Gravatar of Menjanahary R. R.Posted by Menjanahary R. R.Reply
Menjanahary R. R.
Gravatar of Menjanahary R. R.


Reply

I tried to solve Project Euler problem #2 using Recurrence/recurrence.

Assuming genEvenFibonacci is the appropriate funtion in Explicit form, I got what I need like so:

    auto evenfib = recurrence!genEvenFibonacci(2uL, 8uL);

    writeln;
    evenfib.take(11).sum.writeln;

But that's like cheating because there is no prior knowledge of 11.

I just got it manually by peeking at the sequence [2, 8, 34, 144, 610, 2584, 10946, 46368, 196418, 832040, 3524578, 14930352].

14930352 must be filtered out because beyond the limit set!

How to fix that properly using all the standard library capabilities programatically?

I'm thinking of Range and/or std.algorithm.

April 24
Gravatar of H. S. TeohPosted by H. S. Teoh
in reply to Menjanahary R. R.		Reply
H. S. Teoh
Gravatar of H. S. Teoh
Posted in reply to Menjanahary R. R.


Reply
On Wed, Apr 24, 2024 at 08:08:06AM +0000, Menjanahary R. R. via Digitalmars-d-learn wrote:
> I tried to solve Project Euler [problem
> #2](https://projecteuler.net/problem=2) using
> [Recurrence/recurrence](https://dlang.org/library/std/range/recurrence.html).
> 
> Assuming `genEvenFibonacci` is the appropriate funtion in Explicit form, I got what I need like so:
> 
> ```
>     auto evenfib = recurrence!genEvenFibonacci(2uL, 8uL);
> 
>     writeln;
>     evenfib.take(11).sum.writeln;
> ```
> 
> But that's like cheating because there is no prior knowledge of `11`.
> 
> I just got it manually by peeking at the sequence `[2, 8, 34, 144, 610, 2584, 10946, 46368, 196418, 832040, 3524578, 14930352]`.
> 
> `14930352` must be filtered out because beyond the limit set!
> 
> How to fix that properly using all the standard library capabilities programatically?
> 
> I'm thinking of Range and/or std.algorithm.

	evenfib.until!(n => n > 4_000_000).sum.writeln;


T

-- 
The trouble with TCP jokes is that it's like hearing the same joke over and over.
April 24
Gravatar of Menjanahary R. R.Posted by Menjanahary R. R.
in reply to H. S. Teoh		Reply
Menjanahary R. R.
Gravatar of Menjanahary R. R.
Posted in reply to H. S. Teoh


Reply
On Wednesday, 24 April 2024 at 14:22:10 UTC, H. S. Teoh wrote:
> On Wed, Apr 24, 2024 at 08:08:06AM +0000, Menjanahary R. R. via Digitalmars-d-learn wrote:
>> [...]
>
> 	evenfib.until!(n => n > 4_000_000).sum.writeln;
>
>
> T

Thanks a lot! You've made my day 😀