Day 9: Movie Theater
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)
- You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL
FAQ
- What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
- Where do I participate?: https://adventofcode.com/
- Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465
On the line -> inside. The calculation I’ve done is a bit tricksy - vertical lines include the endpoints but horizontal lines exclude them, so that the even-odd rule is followed properly if you’re on the same row as corners. No lines overlap.
I’d considered using the dot product to work out whether the line turned left or right, but there’s a lot of cases to consider and get right. Fair play on computing the normals.
How would you then distinguish between the situations in these two examples?