Drawing a linked list as a tree

I'd like to draw this as a TikZ:

  \
\
+---+---+
| * | * |
+/--+---\
/        \
1          +---+---+
| * | * |
+/--+---\
/        \
2          +---+---+
| * | * |
+/--+---+
/
3


I've tried various things to make an "empty rectangle with a dividing line, to no avail. . . .

• use a node from shapes.multipart library Feb 26, 2016 at 2:09

Here's a simple example to get you started:

\documentclass[tikz]{standalone}

\usepackage{tikz}
\usetikzlibrary{
graphs,
graphdrawing,
shapes.multipart
}
\usegdlibrary{trees}

\tikzset{
rectangle split,
rectangle split horizontal,
rectangle split parts=2,
draw,
/tikz/graphs/as={\nodepart{two} \footnotesize\texttt{*ptr}},
}
}

\begin{document}
\tikz \graph [tree layout] {
1,
2,