matrix_neighbors.py

#!/usr/bin/env python3

TEST = [
    [0, 0, 0, 1, 0, 0, 0],
    [0, 1, 0, 1, 1, 1, 0],
    [0, 0, 1, 1, 0, 1, 0],
    [0, 1, 1, 0, 0, 1, 0],
    [0, 1, 0, 0, 1, 1, 1],
    [0, 1, 1, 0, 0, 1, 1],
    [0, 1, 0, 0, 1, 1, 1],
]

NUM_ROWS = len(TEST)
NUM_COLS = len(TEST[0])

# Validate our data structure
assert NUM_ROWS == NUM_COLS, 'Number of rows must equal number of columns'
for _ in TEST:
    assert NUM_COLS == len(_), 'Row column mismatch'


def calculate_tree_depth(row, col: int, path: list[int]):

    # Don't check if current node is 0
    if not TEST[row][col]:
        return 0

    neighbors = [(row - 1, col), (row, col - 1), (row, col + 1), (row + 1, col)]
    path.append((row, col))
    max_neighbor_depth = 0
    print(path)
    for r, c in neighbors:
        if 0 <= r < NUM_ROWS and 0 <= c < NUM_COLS and (r, c) not in path:  # stay in bounds and don't loop on a path
            max_neighbor_depth = max(max_neighbor_depth, calculate_tree_depth(r, c, path.copy()))
    return max_neighbor_depth + 1


# Iterate over all elements
max_depth = 0
for i in range(0, NUM_ROWS):
    for j in range(0, NUM_COLS):
        max_depth = max(max_depth, calculate_tree_depth(i, j, []))

print(f'Max: {max_depth}')