Help optimize D solution to phone encoding problem: extremely slow performace.

[Renato]

On Tuesday, 16 January 2024 at 22:13:55 UTC, H. S. Teoh wrote:
> used for the recursive calls. Getting rid of the .format ought 
> to speed it up a bit. Will try that now...
>

That will make no difference for the `count` option which is 
where your solution was very slow. To run the slow test manually 
use the `words_quarter.txt` dictionary (the phone numbers file 
doesn't matter much - it's all in the dictionary).

But pls run the benchmarks yourself as I am not going to keep 
running it for you, and would be nice if you posted your solution 
on a Gist for example, pasting lots of code in the forum makes it 
difficult to follow.