aoc

import sys

infile = sys.argv[1] if len(sys.argv) > 1 else "day20data.txt"
data = open(infile).read().strip()
rule, start = data.split("\n\n")
rule = rule.strip()
assert len(rule) == 512

G = set()
for r, line in enumerate(start.strip().split("\n")):
    for c, x in enumerate(line.strip()):
        if x == "#":
            G.add((r, c))


def step(G, on):
    G2 = set()
    rlo = min([r for r, c in G])
    rhi = max([r for r, c in G])
    clo = min([c for r, c in G])
    chi = max([c for r, c in G])
    for r in range(rlo - 5, rhi + 10):
        for c in range(clo - 5, chi + 10):
            rc_str = 0
            bit = 8
            for dr in [-1, 0, 1]:
                for dc in [-1, 0, 1]:
                    if ((r + dr, c + dc) in G) == on:
                        rc_str += 2**bit
                    bit -= 1
            assert 0 <= rc_str < 512
            if (rule[rc_str] == "#") != on:
                G2.add((r, c))
    return G2


def show(G):
    rlo = min([r for r, c in G])
    rhi = max([r for r, c in G])
    clo = min([c for r, c in G])
    chi = max([c for r, c in G])
    for r in range(rlo - 5, rhi + 5):
        row = ""
        for c in range(clo - 5, chi + 5):
            if (r, c) in G:
                row += "#"
            else:
                row += " "
        print(row)


for t in range(50):
    if t == 2:
        print(len(G))
    G = step(G, t % 2 == 0)
print(len(G))