Advent of Code Day 6

Advent of Code Day 6

[John Perry]

Today was quite easy, so I used the opportunity to learn about Ada.Strings.Maps, and that made for a much simpler solution to look at.

I do wonder about the efficiency, though. For instance, the only way I could find to count the number of elements in a Character_Set was by converting it to a Character_Sequence. Is there another way?

Re: Advent of Code Day 6

[Jeffrey R. Carter]

On 12/6/20 9:39 AM, John Perry wrote:
> Today was quite easy, so I used the opportunity to learn about Ada.Strings.Maps, and that made for a much simpler solution to look at.
> 
> I do wonder about the efficiency, though. For instance, the only way I could find to count the number of elements in a Character_Set was by converting it to a Character_Sequence. Is there another way?

Probably one of the set pkgs in Ada.Containers or 
PragmARC.Data_Structures.Sets.Discrete might be a better choice than Character_Set

-- 
Jeff Carter
“[T]here are lots of people out there writing software
that should really be out cleaning toilets instead.”
Brian Catlin
173

Re: Advent of Code Day 6

[John Perry]

On Sunday, December 6, 2020 at 5:07:24 AM UTC-6, Jeffrey R. Carter wrote:
> On 12/6/20 9:39 AM, John Perry wrote: 
> >...the only way I could find to count the number of elements in a Character_Set was by converting it to a Character_Sequence. Is there another way?
> Probably one of the set pkgs in Ada.Containers or 
> PragmARC.Data_Structures.Sets.Discrete might be a better choice than Character_Set 

Thanks, Ada.Containers.Hashed_Sets works fine. I look forward to initialization of containers in the next edition of gnat.

john perry

Re: Advent of Code Day 6

[Maxim Reznik]

In my solution I use a custom type - a boolean flag for each character. It takes 26 bytes (or even bits if you add `with Pack` aspect) and should be quite fast. Having this type it's easy to do `and` and `or` between such maps:

https://github.com/reznikmm/ada-howto/blob/advent-2020/md/06/06.md

--
Max

Re: Advent of Code Day 6

[Jeffrey R. Carter]

On 12/7/20 11:55 AM, Maxim Reznik wrote:
> In my solution I use a custom type - a boolean flag for each character. It takes 26 bytes (or even bits if you add `with Pack` aspect) and should be quite fast. Having this type it's easy to do `and` and `or` between such maps:

Fast? I have made no attempt to make my solutions fast, and the slowest one gives

real	0m0.059s
user	0m0.007s
sys	0m0.000s

using the Linux "time" command. All of them have a user time < 10 ms. Almost all 
the real time is doing I/O. And there are no timing requirements.

"Fast" should not be something anyone is worrying about.

-- 
Jeff Carter
"Ah, go away or I'll kill ya."
Never Give a Sucker an Even Break
100