aoc_2023_day_21.py

import pprint

def get_puzzle_input(a_file_name: str) -> list[list[str]]:
    with open(a_file_name) as INFILE:
        return [[x for x in line.rstrip()] for line in INFILE if not line.startswith('!')]


def get_grid(a_puzzle_input: list[list[str]]) -> list[list[str]]:
    return \
        [['#'] + (['#'] * len(a_puzzle_input[0])) + ['#']] + \
        [['#'] + line + ['#'] for line in a_puzzle_input] + \
        [['#'] + (['#'] * len(a_puzzle_input[0])) + ['#']]


def get_start(a_grid: list[list[str]]) -> tuple[int, int]:

    for row in range(len(grid)):
        for col in range(len(grid[0])):
            if grid[row][col] == 'S':
                return row, col

    assert False, 'How did I get here?'

    return -1, -1


puzzle_input = get_puzzle_input('advent_of_code_2023_day_21.txt')
grid = get_grid(puzzle_input)
pprint.pprint(grid)

row, col = get_start(grid)
print(f'{row}, {col}')