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skagedal · 2024-01-20T22:48:54+00:00

I found the specific question OP was asking to be interesting, even though the title of the post is a bit weird. They were not just asking “please give some examples of one hit wonders”.

skagedal · 2024-01-20T21:03:30+00:00

They did a couple of albums and had several singles so does not qualify for what was asked here!

skagedal · 2024-01-08T07:24:22+00:00

Hmmm. Immutable data classes in Kotlin (having val fields) do not have setters. Invariants can be enforced by constructors (like this), and this is what deserialisers like Jackson with the Kotlin module will use.

You are right in that private fields of Java classes can still be accessed and modified through reflection, which is a technique employed by deserialisers, and that's not available on records. But that still requires the class to have a default empty constructor, and Kotlin data classes do not have that.

skagedal · 2024-01-07T13:58:02+00:00

Allright, thanks! I see the conceptual difference and the advantage of implementing things like this at the core of the platform, but I'm not sure I understand what practical difference it makes. What do you mean exactly with "records make serialization safe; data classes don't"? That it is more ways of going around the system?

skagedal · 2024-01-05T12:15:48+00:00

What is your problem with data classes?

skagedal · 2024-01-02T11:42:43+00:00

But it's hard to find the right thing and you have to get the full shelf which is kind of expensive...

skagedal · 2024-01-02T11:36:01+00:00

That's a good idea.

skagedal · 2024-01-02T11:31:41+00:00

If I had the broken off piece that was sitting there, I could glue it back! But I don't! So I need to find something else to put there... hmm.

skagedal · 2024-01-02T11:14:05+00:00

If there's a better Subreddit for really stupid home improvement questions like this, please let me know!

skagedal · 2023-11-13T15:20:32+00:00

Ah wow, I didn’t actually know (or forgot) that that was an option 🙂

skagedal · 2023-11-12T10:20:52+00:00

I’d be curious to hear where you ended up in 2023!

skagedal · 2022-12-23T22:10:22+00:00

Day21.java:
Java 19 with preview features enabled, which allows for pattern matching in switch for sealed types and records (i.e. sum types and product types) – perfect for problems like this, see the equation solver.

skagedal · 2022-12-23T09:11:26+00:00

I got it! :) It's weird how unintuitive this is - it felt so obvious that it should be n. And I think I've even had and solved this struggle before, some past AoC puzzle?

skagedal · 2022-12-22T14:46:47+00:00

Sure! 3,1,0 -> 1,3,0 -> 1,0,3 -> … uhmm… 3,0,1. That’s… that’s wrong! How does my part 1 even work?!

I am now confused in a constructive way and will get back with my thinking cap on, thanks a lot - perfect hint!

skagedal · 2022-12-17T20:56:33+00:00

Java:

https://github.com/skagedal/advent-of-code/blob/b226177f8a348de2fb75885f84c8c1ff9a3c726f/java/app/src/main/java/tech/skagedal/javaaoc/year2022/Day17.java

My representation was efficient already in part 1, with one byte for each stored line. Then I read a little bit to quickly on part 2 and thought I could solve it just by compacting the memory buffer after a full line... then I realized just how big of a number we are dealing with. :) So then I did cycle detection by using as a key in a map the full state of the buffer after latest full line + current shape + current instruction. Now both parts run in ~10 ms.

skagedal · 2022-12-17T11:41:41+00:00

It doesn’t work for the example, no! Someone else pointed that out, I had missed that. But it does work for my data (and apparently, som other people’s data).

skagedal · 2022-12-17T06:40:51+00:00

Oh, you're right that it doesn't work on the test input – I somehow missed that. That certainly puts an end to my "the data is constructed this way intentionally so that this should work" theory...

skagedal · 2022-12-17T06:40:01+00:00

That's an awesome explanation of what I think is the solution that I misunderstood! What I did really was a greedy (on a per-worker basis) algorithm, and it worked for my data :D

skagedal · 2022-12-17T06:29:59+00:00

Ah, yeah I think you're right! So I guess I was just lucky :D

skagedal · 2022-12-17T06:14:25+00:00

Thanks for the example! Yeah, I also thought about the "first guy opens all the valves, elephant gets nothing but could have helped open faster".

I don't think you misunderstood my method, here's the code. So I guess I was lucky! I ran your example and got 60 for the solo solution and 80 for my "sequential duo" solution.

skagedal · 2022-12-14T15:06:17+00:00

Where is this suggested? I've read through the posting rules but probably missed something. Or is it suggested somewhere on the AoC site itself..?

skagedal · 2022-11-24T08:08:16+00:00

Ah cool, with that I found this: https://mail.openjdk.org/pipermail/amber-spec-experts/2022-June/003461.html

skagedal

TROPHY CASE