day11.py

#!/bin/python

with open('day11.txt') as f:
    octopuses = [list(map(int, list(line.strip()))) for line in f]

def get_neighbours(p):
    neighbours = []
    (x, y) = p[0], p[1]
    if x != 0: 
        neighbours.append((x-1, y))
        if y != 0: neighbours.append((x-1, y-1))
        if y != 9: neighbours.append((x-1, y+1))
    if x != 9:
        neighbours.append((x+1, y))
        if y != 0: neighbours.append((x+1, y-1))
        if y != 9: neighbours.append((x+1, y+1))
    if y != 0: neighbours.append((x, y-1))
    if y != 9: neighbours.append((x, y+1))
    return neighbours

def flash(p):
    (x, y) = p[0], p[1]
    octopuses[y][x] = 0
    flashed.append(p)
    flashes = 1
    for n in get_neighbours(p):
        if n not in flashed: octopuses[n[1]][n[0]] += 1
        if octopuses[n[1]][n[0]] > 9: 
            flashes += flash(n)
    return flashes

flashes = 0
steps = 0
while True:
    flashed = []
    for x in range(10):
        for y in range(10):
            if (x, y) not in flashed: octopuses[y][x] += 1
            if octopuses[y][x] > 9: 
                flashes += flash((x, y))
    steps += 1
    if steps == 100: print('Part One', flashes)
    if len(flashed) == 100: break

print('Part Two:', steps)