答案1
我会在 TikZ 中执行此操作。版本 2.10 手册的第 18.1 节介绍了如何制作树。树上的节点有点不标准，但关于多部分节点的第 16.3 节可能会有所帮助。
以下是一个快速模型：
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes}
\begin{document}
\begin{center}
\begin{tikzpicture}
\tikzstyle{bplus}=[rectangle split, rectangle split horizontal,rectangle split ignore empty parts,draw]
\tikzstyle{every node}=[bplus]
\tikzstyle{level 1}=[sibling distance=60mm]
\tikzstyle{level 2}=[sibling distance=15mm]
\node {15} [->]
child {node {3 \nodepart{two} 7}
child {node {1 \nodepart{two} 2}}
child {node {4 \nodepart{two} 6}}
child {node {8 \nodepart{two} 9}}
}
child {node {21 \nodepart{two} 28 \nodepart{three} 32 \nodepart{four} 50}
child {node {17 \nodepart{two} 20}}
child {node {22 \nodepart{two} 25}}
child {node {28 \nodepart{two} 30}}
child[sibling distance=25mm] {node {34 \nodepart{two} 38 \nodepart{three} 44 \nodepart{four} 47}}
child[sibling distance=25mm] {node {53 \nodepart{two} 54 \nodepart{three} 60 \nodepart{four} 88}}
}
;\end{tikzpicture}
\end{center}
\end{document}
像您的示例一样，要使垂直线加倍需要做更多工作。形状的代码rectangle split可能需要更改。
答案2
我找到了.sty新南威尔士大学王伟教授编写的一份文件，看起来很不错：
http://www.cse.unsw.edu.au/~weiw/tools.html
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{weiwBTree}
\typeout{Document Style `weiw_BTree - Support drawing B+-Tree (ver 0.999)}
\RequirePackage{tikz}
\RequirePackage{ifthen}
% use libraries
\usetikzlibrary{arrows,shapes,snakes,matrix}
%% global declaration
\tikzstyle{btreeptr} = [draw, semithick, fill=blue!50, minimum height=2em]
\tikzstyle{btreeval} = [draw, semithick, fill=yellow!30, minimum size=2em]
\tikzstyle{btreevale} = [draw,semithick, fill=green!30, minimum size=2em]
\tikzstyle{btlink} = [draw, semithick, ->, >=triangle 45]
%% macro
%% helper macros
\newcommand{\suppressemptystr}[1]{% leave blank for entries in leaf nodes
\ifthenelse{\equal{#1}{}}%
{%
\relax%
}%
% Else
{%
#1\textsuperscript{*}%
}%
}%
\newcommand{\xyshift}[3]{% help to place the nodes
\begin{scope}[xshift=#1, yshift=#2]
#3
\end{scope}%
}
%% Common btree macros
\newcommand{\btreelink}[2]{% #1: src node; #2: dest node;
\draw[btlink] ([yshift=3pt] #1.south) -- (#2-b.north);
}
\newcommand{\btreelinknorth}[2]{% #1: src node; #2: dest node;
\draw[btlink] ([yshift=3pt] #1.south) -- (#2.north);
}
\newcommand{\btreetriangle}[2]{% #1: node name; #2 text inside
\node[anchor=north, regular polygon, regular polygon sides=3, draw] (#1) {#2};
}
%%======================================================================
%% btree with capacity = 4
\newcommand{\btreeinodefour}[5]{%
\matrix [ampersand replacement=\&] (#1)
{
\node[btreeptr] (#1-1) {\vphantom{1}}; \& \node[btreeval] (#1-a) {#2}; \&
\node[btreeptr] (#1-2) {\vphantom{1}}; \& \node[btreeval] (#1-b) {#3}; \&
\node[btreeptr] (#1-3) {\vphantom{1}}; \& \node[btreeval] (#1-c) {#4}; \&
\node[btreeptr] (#1-4) {\vphantom{1}}; \& \node[btreeval] (#1-d) {#5}; \&
\node[btreeptr] (#1-5) {\vphantom{1}}; \\
};
}
\newcommand{\btreelnodefour}[5]{%
\matrix [ampersand replacement=\&, outer sep=0pt, matrix anchor=north] (#1)
{
\node[btreevale] (#1-a) {\suppressemptystr{#2}}; \&
\node[btreevale] (#1-b) {\suppressemptystr{#3}}; \&
\node[btreevale] (#1-c) {\suppressemptystr{#4}}; \&
\node[btreevale] (#1-d) {\suppressemptystr{#5}}; \\
};
}
%%======================================================================
%% btree with capacity = 3
\newcommand{\btreeinodethree}[4]{%
\matrix [ampersand replacement=\&] (#1)
{
\node[btreeptr] (#1-1) {\vphantom{1}}; \& \node[btreeval] (#1-a) {#2}; \&
\node[btreeptr] (#1-2) {\vphantom{1}}; \& \node[btreeval] (#1-b) {#3}; \&
\node[btreeptr] (#1-3) {\vphantom{1}}; \& \node[btreeval] (#1-c) {#4}; \&
\node[btreeptr] (#1-4) {\vphantom{1}}; \\
};
}
\newcommand{\btreelnodethree}[4]{%
\matrix [ampersand replacement=\&, outer sep=0pt, matrix anchor=north] (#1)
{
\node[btreevale] (#1-a) {\suppressemptystr{#2}}; \&
\node[btreevale] (#1-b) {\suppressemptystr{#3}}; \&
\node[btreevale] (#1-c) {\suppressemptystr{#4}}; \\
};
}
%%======================================================================
%% simple example
% \begin{center}
% \scalebox{0.7}{
% \begin{tikzpicture}
% %
% \btreeinodefour{root}{13}{17}{24}{30};
% \xyshift{-40mm}{-20mm}{\btreelnodefour{n1}{2}{3}{5}{7}}
% \xyshift{-0mm}{-20mm}{\btreelnodefour{n2}{14}{16}{}{}}
% \xyshift{40mm}{-20mm}{\btreelnodefour{n3}{19}{20}{22}{}}
% \xyshift{80mm}{-20mm}{\btreelnodefour{n4}{24}{27}{29}{}}
% \xyshift{120mm}{-20mm}{\btreelnodefour{n5}{33}{34}{38}{39}}
% %
% \foreach \x in {1,2,...,5} { \btreelink{root-\x}{n\x} }
% \end{tikzpicture}
% }
% \end{center}