GameOfLife.py

class Solution:
    def gameOfLife(self, board: List[List[int]]) -> None:
        ROWS , COLS = len(board) , len(board[0])

        def countNeighbours(r,c):
            nei = 0
            for i in range(r-1, r+2):
                for j in range(c-1,c+2):
                    if ((i==r and j == c) or i< 0 or j<0 or i == ROWS or j == COLS) :
                        continue
                    if board[i][j] in [1,3]:
                        nei +=1
            return nei

        for r in range(ROWS):
            for c in range(COLS):
                nei = countNeighbours(r,c)
                if board[r][c]:
                    if nei in [2,3]:
                        board[r][c] =3
                elif nei == 3:
                        board[r][c]=2

        for r in range(ROWS):
            for c in range(COLS):
                if board[r][c] == 1:
                     board[r][c] = 0
                elif board[r][c] in [2,3]:
                     board[r][c] = 1