Day 6: Guard Gallivant
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
That’s about how long it takes for my python solution to complete.
How did you detect loops? I just ran for 100000 steps to see if I escaped, got my time down to 3s by doing only 10000 steps.
Not who you asked but: I save coordinates and direction into a vector each time the guard faces a #. Also every time the guard faces a #, I check if the position exists in the vector, if true, it’s an infinite loop. 78ms rust aolution.
That’s probably quite optimal, compared with checking every state in the path, or running off a fixed number of steps
I added each visited position/direction to a set, and when a ‘state’ is reached again you have entered a loop:
v = set() while t[g.r][g.c] != 'X': state = (g.r, g.c, g.d) if state in v: acc += 1 break v.add(state) g.move(t)
You can view my full solution here.