public boolean checkZone(char[][] board, int centerX, int centerY){
		int bit = 0;
		int[] x = {-1, 0, 1}, y = {-1, 0, 1};
		for(int i = 0; i < 3; i++)
			for(int j = 0; j < 3; j++){
				if(board[centerX + x[i]][centerY + y[j]] == '.') continue;
				if(((1 << (board[centerX + x[i]][centerY + y[j]] - '0')) & bit) > 0) return false;
				bit |= 1 <<(board[centerX + x[i]][centerY + y[j]] - '0');
			}
		
		return true;
	}