AOC 2023, day 13, p2

aoc_2023_day12_p2.py

import numpy as np

grids = [np.array(list(map(list, grid.splitlines()))) for grid in inp.split("\n\n")]

def is_reflection(arr, col):
    a1, a2 = arr[:, :col], np.fliplr(arr[:, col:])
    l1, l2 = a1.shape[1], a2.shape[1]
    if l1 > l2:
        return np.all(a2 == a1[:,-l2:])
    else:
        return np.all(a1 == a2[:,-l1:])
    
def get_reflection(arr, dim):
    if dim == 1:
        arr = arr.transpose()
    for col in 1 + np.all(arr[:, :-1] == arr[:, 1:], axis=0).nonzero()[0]:
        if is_reflection(arr, col):
            return col
        
part_one = 0
for i, g in enumerate(grids):
    for dim, w in zip([0, 1], [1, 100]):
        if (idx := get_reflection(g, dim)) is not None:
            part_one += w * idx
            break
print(part_one)