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Advent of Code 2024 - Historian goes looking for history in all the wrong places (adventofcode.com)

submitted 2 weeks ago by [email protected] to c/[email protected]

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copy pasting the rules from last year's thread:

Rules: no spoilers.

The other rules are made up aswe go along.

Share code by link to a forge, home page, pastebin (Eric Wastl has one here) or code section in a comment.

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[–] [email protected] 4 points 1 week ago* (last edited 1 week ago) (5 children)

Re: day 7 parts 1 and 2

same here, I was dicking around with combinatorics to get all combos of plus and multiply but realized before I got to the end it was gonna take too long. Then I figured that a DFS was the way to go.

I tried to optimize a bit by exiting early if the cumulative result became too large, but for some reason that gave me incorrect (too low) answers. Part 2 runs in around 1 min anyway.

https://github.com/gustafe/aoc2024/blob/main/d07-Bridge-Repair.pl

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

re: branch cutting

IDK if this is what your issue was, but one thing I ran into was that if you do something like if (current_total >= target) prune(), this can be problematic because if the tail end of the data is 0s and 1s, you exit too early. Basically I would prune strictly when the current total > target.

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

re: branch cutting

thanks for the tip, I looked into it again and I found I was cutting in the wrong place. Fixed now, and halves the time for part 2

[–] [email protected] 2 points 1 week ago

We love to see it

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