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

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🦌 - 2023 DAY 16 SOLUTIONS -🦌 (programming.dev)

submitted 11 months ago by [email protected] to c/[email protected]

11 comments fedilink hide all child comments

Day 16: The Floor Will Be Lava

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[–] [email protected] 1 points 11 months ago

C

Just tracing the ray. When it splits, recurse one way and continue the other. Didn't bother with a direction lookup table this time, just a few ifs. The ray ends when it goes out of bounds or a ray in that direction has been previously traced on a given cell (this is tracked with a separate table).

It would've been straightforward if I hadn't gotten the 'previously visited' check wrong 😞. I was checking against the direction coming in of the tile but marking the direction going out.

Ray function:

static void
ray(int x, int y, int dir)
{
	int c;

	while (x>=0 &amp;&amp; y>=0 &amp;&amp; x