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๐ป - 2024 DAY 19 SOLUTIONS -๐ป
(programming.dev)
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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.
Solution Threads
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2 | 3 | 4 | 5 | 6 | 7 | 8 |
9 | 10 | 11 | 12 | 13 | 14 | 15 |
16 | 17 | 18 | 19 | 20 | 21 | 22 |
23 | 24 | 25 |
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console.log('Hello World')
Rust
First part is solved by making a regex of the available towels, like
^(r|wr|bg|bwu|rb|gb|br)*$
for the example. If a design matches it, then it can be made. This didn't work for the second part, which is done using recursion and memoization instead. Again, it was quite surprising to see such a high solution number. 32 bits were not enough (thanks, debug mode overflow detection).Solution
Also on github
How fast was the regex approach?
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.
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.
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
String
s.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.