TikZ-Tree 中某些类型节点的边缘样式

Question

我有以下 Ti钾Z 树：

\begin{tikzpicture}[grow=south, level 1/.style={sibling distance=50pt}, level 3/.style={sibling distance=25pt}, level distance=30pt, every node/.style={draw, circle, inner sep=0pt, minimum size=5pt}, inner/.style={fill=black}]
    \node {}
        child {node[inner] {}
            child {node {} 
                child {node[inner] {}
                    child {node {}
                        child {node[inner] {}
                            child {node {}}
                        }
                        child {node[inner] {}
                            child{ node {}}
                        }
                    }
                }
                child {node[inner] {}
                    child {node {}}
                }
            }
        }
        child {node[inner] {}
            child {node {}
                child {node[inner] {}
                    child {node {}
                        child {node[inner] {}
                            child{ node {}}
                        }
                    }
                }
                child {node[inner] {}
                    child {node {}}
                }
            }
        }
        ;
\end{tikzpicture}

由此得出下图：

如您所见，黑色顶点 ( [inner]) 只有一个子节点。我需要的是这个唯一子节点的边是very thick。有没有一种巧妙的方法可以做到这一点，也许在 内inner/.style={...}？

Answer 1

我建议切换到森林。在那里你可以实施简单的规则，例如

where n children=1{<do something>}{<otherwise>}

然而，看着你的树，我觉得实际的规则是

if={isodd(level)}{fill,for descendants={edge={very thick}}}{for descendants={edge={thin}}}

无论如何，我添加了这两个选项。如果真正的规则与它们两个不同，请告诉我。

\documentclass{article}
\usepackage[edges]{forest}
\begin{document}
\begin{forest}
for tree={grow=south,circle,draw,
where n children=1{fill,for descendants={edge={very thick}}}{for descendants={edge={thin}}},
}
[
 [
  [
   [
    [
     [[]]
     [[]]
    ]
   ]
   [[]]
  ]
 ]
 [
  [
   [[[[]]]]
   [[]]
  ]
 ]
]
\end{forest}
\begin{forest}
for tree={grow=south,circle,draw,
if={isodd(level)}{fill,for descendants={edge={very thick}}}{for descendants={edge={thin}}}
}
[
 [
  [
   [
    [
     [[]]
     [[]]
    ]
   ]
   [[]]
  ]
 ]
 [
  [
   [[[[]]]]
   [[]]
  ]
 ]
]
\end{forest}
\end{document}