Advent Of Code

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An unofficial home for the advent of code community on programming.dev!

Advent of Code is an annual Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like.

AoC 2024

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👻 - 2024 DAY 19 SOLUTIONS -👻 (programming.dev)

submitted 6 days ago by [email protected] to c/[email protected]

31 comments fedilink hide all child comments

Day 19 - Linen Layout

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[–] [email protected] 2 points 6 days ago (1 children)

How fast was the regex approach?

[–] [email protected] 3 points 6 days ago (1 children)

About 3ms. A manual implementation might be a bit faster, but not by much. The regex crate is quite optimized for pretty much these problems.

[–] [email protected] 2 points 6 days ago* (last edited 6 days ago) (1 children)

Wow, that is very fast, nice. I was happy with 120ms, seems I'm leaving a lot of performance on the table.

Edit: Regex cut my total time in half, but I am measuring the whole execution, still a massive improvement.

[–] [email protected] 3 points 6 days ago (1 children)

The 3ms are for part 1 only, part 2 takes around 27ms. But I see that our approaches there are very similar. One difference that might make an impact is that you copy the substrings for inserting into the hashmap into Strings.

[–] [email protected] 2 points 6 days ago* (last edited 6 days ago)

Removing the string copy with the length->count array from @sjmulder saved me 20ms, so not super significant. I'll have to play the the profiler and see what I am doing wrong.

I think your approach looks a lot more Rust-like, which I like. Part 1 in 4 lines is very nice.