☰

仅向树的某些边缘添加箭头

tag-icon • tag-icon tikz-pgf tikz-trees
仅向树的某些边缘添加箭头

我想要绘制如下的图：

在此处输入图片描述

\begin{tikzpicture} [ level 1/.style={sibling distance=30mm}, 
level 2/.style={sibling distance=15mm},
level 3/.style={sibling distance=7mm},
triangle/.style = {fill=blue!20, regular polygon, regular polygon sides=3},
node rotated/.style = {rotate=180},
border rotated/.style = {shape border rotate=180}]
\node[triangle] {1.5} 
    child {node[circle, draw, fill=blue!20] {1.5} 
        child {node[triangle, border rotated] {2} 
            child {node {2}}
            child {node {2}}}
        child {node[triangle, border rotated] {1}
            child {node {1}}
            child {node {2}}}}
    child {node[circle, draw, fill=blue!20] {-0.5}
        child {node[triangle, border rotated] {0}
            child {node {0}}
            child {node {2}}}
        child {node[triangle, border rotated] {-1}
            child {node {-1}}
            child {node {0}}}};
\end{tikzpicture}

这是我的代码。我看过这个问题TikZ：使用“子”符号将边变成箭头 但是当我添加时edge to parent，它会使整棵树的边缘都带有箭头。我不知道如何只将一条边变成红色和箭头，而不改变其他边。谢谢你的帮助。

答案1

你始终可以edge from parent在所需节点上声明样式，然后在后代分支中恢复它

\documentclass[border=2mm,tikz]{standalone}
\usetikzlibrary{shapes.geometric}

\begin{document}
\begin{tikzpicture} [ level 1/.style={sibling distance=30mm}, 
level 2/.style={sibling distance=15mm},
level 3/.style={sibling distance=7mm},
triangle/.style = {fill=blue!20, regular polygon, regular polygon sides=3},
node rotated/.style = {rotate=180},
border rotated/.style = {shape border rotate=180}]
\node[triangle] {1.5} 
    child {node[circle, draw, fill=blue!20] {1.5} edge from parent[->, thick, draw=red]
        child {node[triangle, border rotated] {2} edge from parent[-, thin, draw=black] 
            child {node {2}}
            child {node {2}}}
        child {node[triangle, border rotated] {1} edge from parent[-, thin, draw=black]
            child {node {1}}
            child {node {2}}}}
    child {node[circle, draw, fill=blue!20] {-0.5}
        child {node[triangle, border rotated] {0}
            child {node {0}}
            child {node {2}}}
        child {node[triangle, border rotated] {-1}
            child {node {-1}}
            child {node {0}}}};
\end{tikzpicture}
\end{document}

在此处输入图片描述

答案2

使用样式的答案：

输出类似于@Ignasi 的答案输出，但我使用了样式并且没有将箭头弄粗：

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes}
\begin{document}
\begin{tikzpicture} [ level 1/.style={sibling distance=30mm}, 
level 2/.style={sibling distance=15mm},
level 3/.style={sibling distance=7mm},
triangle/.style = {fill=blue!20, regular polygon, regular polygon sides=3},
node rotated/.style = {rotate=180},
border rotated/.style = {shape border rotate=180},
mystyle/.style={-latex,red},
mydefault/.style={-,black}
]
\node[triangle] {1.5} 
    child[mystyle]  { node[circle, fill=blue!20,draw=black,text=black]  {1.5}
        child[mydefault] {node[triangle, border rotated] {2} 
            child {node {2}}
            child {node {2}}}
        child[mydefault] {node[triangle, border rotated] {1}
            child {node {1}}
            child {node {2}}}}
    child {node[circle, draw, fill=blue!20] {-0.5}
        child {node[triangle, border rotated] {0}
            child {node {0}}
            child {node {2}}}
        child {node[triangle, border rotated] {-1}
            child {node {-1}}
            child {node {0}}}};
\end{tikzpicture}
\end{document}

附言：这个答案是我几个小时前写的（但后来有一些关于工作上的紧急闲聊），只是因为它已经准备好了才添加的。

相关内容