\documentclass[12pt]{standalone}

\usepackage{tikz}
\usepackage{ctex}

\begin{document}
\begin{tikzpicture}

\matrix at (-3,0) {
    \scoped[<-,every node/.style={circle,draw}]
    \node {1}
        child {node {2}}
        child {node {3}
            child {node {4}}
            child {node {5}}};
\\};

\draw[->] (-1,0) -- node[above] {路径压缩} (1,0);

\matrix at (4,0) {
    \scoped[<-,every node/.style={circle,draw}]
    \node {1}
        child {node {2}}
        child {node {3}}
        child {node {4}}
        child {node {5}};
\\};

\end{tikzpicture}
\end{document}