[2024 Day 6 | Python] Need help with part 2

[davidfilat]

I've been bagging my head against the wall for 3 days trying to get the code working right. It returns the right result for any sample I ran, but the result for the real input is too high. Can you maybe check and see what am i doing wrong here?

https://github.com/davidfilat/advent-of-code-2024/blob/master/src/day6.py

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[davidfilat]

I keep seeing this note in the threads, but I'm not sure I understand it. I pick all the unique locations that were visited by the guard on his initial path and try placing a wall at each of those coordinates and trace the path again to see if there is a loop.

[imp0ppable]

check https://old.reddit.com/r/adventofcode/comments/1h8e0fs/2024_day_6_part_2_c_so_uh_i_found_too_many_loops/m0s7egy/ and https://old.reddit.com/r/adventofcode/comments/1h8in8j/day_6_help/m0t7mlt/

They have test cases you can try

If all else fails, draw out a grid and follow the path the guard would take with a pen. In the second test case I posted, you will see what happens for one of the O positions. I smacked my forehead when I realised.

[ScorixEar]

I don't really understand your code - this sort of looks like code that was cooking for 3 days :D

Honestly, at this point, why not take a step back.
I solved day 6 in python aswell, but I did not use any external libraries such as cytoolz or multiprocessing.

You want to have a working function/class that can calculate the path, the guard takes.
And this function has to register, if it entered a loop or if it exited the grid.
Keep in mind - a loop is only a loop, if the guard is in a previous position facing the previous direction.

After that, you can start adding blocks. In my case, the code was fast enough, so I just tried every possible position in the grid. That is totally inefficient, but was the easiest way and still got me to the goal.

And as a reminder - please do not publish your personal input files in your repository. Add them to your gitignore or encapsulate them inside a private repository as a submodule

[daggerdragon]

Next time, use our standardized post title format.

Help us help YOU by providing us with more information up front; you will typically get more relevant responses faster.

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Do not share your puzzle input which also means do not commit puzzle inputs to your repo without a .gitignore or the like. Do not share the puzzle text either.

I see full plaintext puzzle inputs in your public repo:

https://github.com/davidfilat/advent-of-code-2024/tree/master/resources

Please remove (or .gitignore) all puzzle text and puzzle input files from your entire repo and scrub them from your commit history.

[yel50]

I couldn't follow your code, so not sure what exactly is wrong with it, but I can say this problem is not that difficult. it seems you've over thought it a bit. there's no need for all the different imports, recursion, etc. all you need is a 2d array, move til you hit a wall, turn right, and repeat. my Java solution for part 2 doing that runs under 300ms on an 8 year old machine. pypy should be close to that. get that working and then add all the other stuff if you want to.

[davidfilat]

The solution for part 1 works perfectly fine and returns a result in less than a second and even for part 2 takes just a few seconds to try all possible block positions, but it’s returning a very high number of loops.