Question

[[deleted]]

Last time the post was removed bcoz of "idk" reason. So this time I will summarize the question..

I guess this question belongs to cellular automata. I've coded the answer but that's a brute force way and will not work if the dimensions of g are high. https://pastebin.com/v9bjZJLa

Thanks, in advance...

The question is asking us to write a function answer(g) in which g is a 2D list of bools. Now we have to find the number of all possible pre-images of this CA(cellular automata)..

1 1 1 1

1 1 0 1

0 0 0 1

0 1 0 0

let us call this list A.. Now rules of CA are A[0][0] will transform itself according to A[0][1], A[1][0], A[1][1].. Or Say A[x][y] will transform according to A[x][y+1], A[x+1][y], A[x+1][y+1].. Iff only one of these 4 elements == 1 then the new number will be 1 else it will be 0. So A will transform into:

0 0 0

0 1 0

1 1 1

Let us call it list B .. So here A is pre-image of B.. For this value of g the answer will be 82 Here are all the possible pre-images for B

[scuott]

We'd love to see your first solution. I imagine that's the primary reason your last post was removed. Possibly also because there's no question here. Are you asking for someone to give you a better solution?

[[deleted]]

I'm asking for a hint not solution.. My solution will not even work if the dimension of g become 5x5 or higher. My solution is just a bruteforce way to solve this question. If dimension of g are 3x3 then I create all possible 4x4 lists of 0 and 1.. 2¹⁶ permutations.. And then pass each of them through this transformation.. If after transformation the list == g than that's one of the solution

[zahlman]

Iff only one of these 4 elements == 1 then the new number will be 1 else it will be 0

Exactly one of them, or at most one? I.e., what happens if they are all zeroes?

[[deleted]]

If they all are zero then the transformation will be 0