day12.py

data = """<x=-1, y=7, z=3>
<x=12, y=2, z=-13>
<x=14, y=18, z=-8>
<x=17, y=4, z=-4>""".splitlines()
from itertools import combinations
import re

pattern = re.compile(r"<x=(\-?\d+), y=(\-?\d+), z=(\-?\d+)>")

moons = [
    [
        [
            int((match := pattern.match(i)).group(1)),
            int(match.group(2)),
            int(match.group(3)),
        ],
        [0, 0, 0],
    ]
    for i in data
]

x_states = set()
y_states = set()
z_states = set()

x_loop = -1
y_loop = -1
z_loop = -1

step = 0

x_state = (
    moons[0][0][0],
    moons[1][0][0],
    moons[2][0][0],
    moons[0][1][0],
    moons[1][1][0],
    moons[2][1][0],
)

y_state = (
    moons[0][0][1],
    moons[1][0][1],
    moons[2][0][1],
    moons[0][1][1],
    moons[1][1][1],
    moons[2][1][1],
)

z_state = (
    moons[0][0][2],
    moons[1][0][2],
    moons[2][0][2],
    moons[0][1][2],
    moons[1][1][2],
    moons[2][1][2],
)

while -1 in [x_loop, y_loop, z_loop]:
    if x_state in x_states and x_loop == -1:
        x_loop = step
    else:
        x_states.add(x_state)

    if y_state in y_states and y_loop == -1:
        y_loop = step
    else:
        y_states.add(y_state)

    if z_state in z_states and z_loop == -1:
        z_loop = step
    else:
        z_states.add(z_state)

    for moon, moon2 in combinations(moons, 2):
        x1, y1, z1 = moon[0]
        x2, y2, z2 = moon2[0]

        if x1 > x2:
            moon[1][0] -= 1
            moon2[1][0] += 1

        if x1 < x2:
            moon[1][0] += 1
            moon2[1][0] -= 1

        if y1 > y2:
            moon[1][1] -= 1
            moon2[1][1] += 1

        if y1 < y2:
            moon[1][1] += 1
            moon2[1][1] -= 1

        if z1 > z2:
            moon[1][2] -= 1
            moon2[1][2] += 1

        if z1 < z2:
            moon[1][2] += 1
            moon2[1][2] -= 1

    for moon in moons:
        moon[0][0] += moon[1][0]
        moon[0][1] += moon[1][1]
        moon[0][2] += moon[1][2]

    step += 1
    if step == 1000:
        print(sum(sum(abs(i) for i in j[0]) * sum(abs(i) for i in j[1]) for j in moons))

    x_state = (
        moons[0][0][0],
        moons[1][0][0],
        moons[2][0][0],
        moons[0][1][0],
        moons[1][1][0],
        moons[2][1][0],
    )

    y_state = (
        moons[0][0][1],
        moons[1][0][1],
        moons[2][0][1],
        moons[0][1][1],
        moons[1][1][1],
        moons[2][1][1],
    )

    z_state = (
        moons[0][0][2],
        moons[1][0][2],
        moons[2][0][2],
        moons[0][1][2],
        moons[1][1][2],
        moons[2][1][2],
    )

from math import gcd


def lcm(a, b):
    """Compute the lowest common multiple of a and b"""
    return a * b // gcd(a, b)


print(lcm(lcm(x_loop, y_loop), z_loop))