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 2023

Solution Threads

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4	5	6	7	8	9	10
11	12	13	14	15	16	17
18	19	20	21	22	23	24
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Rules/Guidelines

Follow the programming.dev instance rules
Keep all content related to advent of code in some way
If what youre posting relates to a day, put in brackets the year and then day number in front of the post title (e.g. [2023 Day 10])
When an event is running, keep solutions in the solution megathread to avoid the community getting spammed with posts

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Advent of Code Homepage

Credits

Icon base by Lorc under CC BY 3.0 with modifications to add a gradient

console.log('Hello World')

founded 1 year ago

MODERATORS

Ategon

[email protected]

CameronDev

❄️ - 2023 DAY 3 SOLUTIONS -❄️ (self.advent_of_code)

submitted 11 months ago* (last edited 11 months ago) by Ategon to c/advent_of_code

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Day 3: Gear Ratios

Megathread guidelines

Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
Code block support is not fully rolled out yet but likely will be in the middle of the event. Try to share solutions as both code blocks and using something such as https://topaz.github.io/paste/ or pastebin (code blocks to future proof it for when 0.19 comes out and since code blocks currently function in some apps and some instances as well if they are running a 0.19 beta)

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What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
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[–] [email protected] 5 points 11 months ago

I've been using Regexes for every day so far, this time it helped in finding numbers along with their start and end position in a line. For the second part I mostly went with the approach of part 1 which was to look at all numbers and then figure out if it has a part symbol around it. Only in part 2 I saved all numbers next to a gear * in a hash table that maps each gear position to a list of adjacent numbers. Then in the end I can just look at all gears with exactly 2 numbers attached.

Also it has to be said, multiplying two numbers is the exact opposite of getting their ratio!