Advent Of Code

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An unofficial home for the advent of code community on programming.dev! Other challenges are also welcome!

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.

Everybody Codes is another collection of programming puzzles with seasonal events.

AoC 2025

Solution Threads

M	T	W	T	F	S	S
1	2	3	4	5	6	7
8	9	10	11	12

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console.log('Hello World')

founded 2 years ago

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🌻 - 2024 DAY 12 SOLUTIONS -🌻 (programming.dev)

submitted 11 months ago by CameronDev@programming.dev to c/advent_of_code@programming.dev

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Day 12: Garden Groups

Megathread guidelines

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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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[–] RagingHungryPanda@lemm.ee 2 points 11 months ago

hey thanks!

I didn't check any other solutions before finishing (currently wondering way day 13 is too low), but I thought that trying to traverse fences would be a pain and since I have everything separated by regions and not traversing the array, counting corners never came to mind.

But the thought that I had was that for each region, all points will be a straight line in the V or H orientations, so if I can go up and down and count when last != next - 1, then that'll tell me that that is a contiguous piece of fence.

The idea isn't too hard, for tracking the XAxis it's

region.GroupBy(YAxis) // row
.Select(group => 
    group.Sort(g => g.XAxis) // column
        .Window(a,b => a != b - 1 ? 1 : 0).Sum()
.Sum()

Except that I used a different splitting method and that came to me later.