advent_11.py

def key(x,y):
  return "{0}-{1}".format(x, y)

def energize(octopi, x, y, flashed):
  if y < 0 or y >= len(octopi) or x < 0 or x >= len(octopi[y]):
    return
  if key(x, y) in flashed:
    return
  octopi[y][x] += 1
  if octopi[y][x] > 9:
    flashed[key(x, y)] = (x, y)
    energize(octopi, x - 1, y - 1, flashed)
    energize(octopi, x, y - 1, flashed)
    energize(octopi, x + 1, y - 1, flashed)
    energize(octopi, x - 1, y, flashed)
    energize(octopi, x + 1, y, flashed)
    energize(octopi, x - 1, y + 1, flashed)
    energize(octopi, x, y + 1, flashed)
    energize(octopi, x + 1, y + 1, flashed)

def simulate(octopi):
  flashed = {}
  for y, row in enumerate(octopi):
    for x, _ in enumerate(row):
      energize(octopi, x, y, flashed)
  for key in flashed:
    x, y = flashed[key]
    octopi[y][x] = 0
  return len(flashed)

if __name__ == '__main__':
  with open('input.txt') as data:
    octopi = []
    for line in data:
      line = line.strip()
      octopi.append([int(item) for item in line])
    flashes = 0
    flashes_at_100 = 0
    step = 0
    while True:
      step += 1
      step_flashes = simulate(octopi)
      flashes += step_flashes
      if step == 100:
        flashes_at_100 = flashes
      if step_flashes == len(octopi) * len(octopi[0]):
        break
    print(flashes_at_100, step)