Advent of Code 2024 Day 12

— Day 12: Garden Groups —

We have a gardening map where the plants grow all over the place.

What is the total price of fencing all regions on your map?

import numpy as np

with open('data-2024-12.txt', 'r') as f:
    inp = f.read().splitlines()

grid = [list(x) for x in inp]

fences = np.array(grid)

fence_space = np.empty([281, 281], dtype=str)
fence_space[:] = ' '

for i in range(140):
    for j in range(140):
        fence_space[i*2+1,j*2+1] = fences[i,j]

Loop through and mark all the boundaries.

# outside boundaries for good luck
for k in range(1, 281):
    fence_space[0,k] = '-'
    fence_space[280,k] = '-'
    fence_space[k,0] = '|'
    fence_space[k,280] = '|'



for i in range(1, 280, 2):
    for j in range(2, 279, 2):
        if fence_space[i,j-1] != fence_space[i,j+1]: 
            fence_space[i,j] = '|'
            

for i in range(2, 279, 2):
    for j in range(1, 280, 2):
        if fence_space[i-1,j] != fence_space[i+1,j]: 
            fence_space[i,j] = '-'

Boundaries are done, now we have to pick out the groups. I think, pick off the bits and search around for how many are in the group.

def check_empty():
    # see if we have anything left from the original array
    pass

def gather_garden():
    # loop around the place to see what's included in the garden
    pass

while True: 
    # pick a place to start searching
    break
    # count the boundaries
    
    # count the area
    
    # remove the area from consideration

Well, do I need to create an elaborate array of spacings? Can I just pick out the garden and work the boundary afterwards? I would still be using the same gather function.

There is no overlap between the fences, I’m not counting unique fence parts, but I do need to maintain the shape of the gardens.