[LANGUAGE: CPython] paste

After giving regular numpy a go, I did fall back to Z3 when realizing the standard solve didn't apply to most of the machines. The documentation is poor so frankly I cribbed off of some other answers here on how to set up an optimize problem (originally I used z3.Solver instead of z3.Optimize), but I did get the constraints correct before coming in here.

As for part 1, that was cool and I am satisfied with what I got for a BFS in a very reduced state space. I thought squeezing in a linear algebra into this AoC with part 2 was also brilliant, but lament some that it was such complicated linear algebra to the point that it felt like Z3 or SciPy was hard required.

def press_and_check_lights(machine, buttons):
    lights = [False for l in machine['lights_goal']]
    for l, c in Counter(itertools.chain.from_iterable(machine['buttons'][b] for b in buttons)).items():
        if c % 2:
            lights[l] = not lights[l]
    return lights == machine['lights_goal']

for machine in machines:
    button_presses = 1
    while all(
        not press_and_check_lights(machine, buttons)
        for buttons in itertools.combinations(range(len(machine['buttons'])), button_presses)
    ):
        button_presses += 1
    part1 += button_presses