gameoflife.py

class game_of_life:
    def gameOfLife(self, board: List[List[int]]) -> None:
        """
        Do not return anything, modify board in-place instead.
        """

        # Neighbors array to find 8 neighboring cells for a given cell
        neighbors = [(1,0), (1,-1), (0,-1), (-1,-1), (-1,0), (-1,1), (0,1), (1,1)]

        rows = len(board)
        cols = len(board[0])

        # Create a copy of the original board
        copy_board = [[board[row][col] for col in range(cols)] for row in range(rows)]

        # Iterate through board cell by cell.
        for row in range(rows):
            for col in range(cols):

                # For each cell count the number of live neighbors.
                live_neighbors = 0
                for neighbor in neighbors:

                    r = (row + neighbor[0])
                    c = (col + neighbor[1])

                    # Check the validity of the neighboring cell and if it was originally a live cell.
                    # The evaluation is done against the copy, since that is never updated.
                    if (r < rows and r >= 0) and (c < cols and c >= 0) and (copy_board[r][c] == 1):
                        live_neighbors += 1

                # Rule 1 or Rule 3        
                if copy_board[row][col] == 1 and (live_neighbors < 2 or live_neighbors > 3):
                    board[row][col] = 0
                # Rule 4
                if copy_board[row][col] == 0 and live_neighbors == 3:
                    board[row][col] = 1