The game of life is made up of cells. These are either alive or dead. Cells are normally represented within a 2D list, and look like this:
The cells also have rules that allow us to simulate them. They're normally defined as follows:
- If a cell has less than 2 neighbors, it dies.
- If a cell has 2 or 3 neighbors and is alive, it stays alive.
- If a cell has 3 neighbors and is dead, it becomes alive.
- If a cell has more than 3 neighbors, it dies.
We need to break this down into a couple steps to simulate this correctly. First, we need a way to figure out how many living neighbors a cell has.
To do this, I assign every cell with an x and y coordinate, so our updated picture looks like this:
As a note, the x and y coordinate also match the array indices.
How do we know how many living neighbors a cell has? Let's look at cell (2,1). The cells around that are (1,2), (2,2), (3,2), (1,1), (3,1), (1,0), (2,0), and (3,0). Doing some math, we can turn these into a set of offsets. So given an (x,y) pair, we can go from (x-1,y-1) to (x+1,y+1).
With this information, we can make a new completely empty board, and start filing in cells based on the rules above. If we write a function that tells us how many neighbors a cell has, this turns into a simple set of ifs and else ifs.