\documentclass[tikz,border=2mm, convert]{standalone}
\usetikzlibrary{positioning,arrows.meta}

\begin{document}
\begin{tikzpicture}[>=Stealth, node distance=1.5cm]
    \node[circle, draw, minimum size=1cm] (a_root) {};
    \node[circle, draw, minimum size=1cm, above left=1cm and 0.5cm of a_root] (a_l) {};
    \node[circle, draw, minimum size=1cm, above right=1cm and 0.5cm of a_root] (a_r) {};

    \draw[->] (a_root) -- (a_l) node[midway, anchor=south east, align=right, xshift=1mm, yshift=-5mm] {Get};
    \draw[->] (a_root) -- (a_r) node[midway, anchor=south west, xshift=-1mm, yshift=-5mm] {Get};

    \node[circle, draw, minimum size=1cm, right=3cm of a_root] (b_root) {};
    \node[circle, draw, minimum size=1cm, above left=1cm and 0.5cm of b_root] (b_l) {};
    \node[circle, draw, minimum size=1cm, above right=1cm and 0.5cm of b_root] (b_r) {};

    \draw[->] (b_root) -- (b_l) node[midway, anchor=south east, align=right, xshift=1mm, yshift=-5mm] {Inc};
    \draw[->] (b_root) -- (b_r) node[midway, anchor=south west, xshift=-1mm, yshift=-5mm] {Inc};

    \node[circle, draw, minimum size=1cm, right=3cm of b_root] (c_root) {};
    \node[circle, draw, minimum size=1cm, above left=1cm and 0.5cm of c_root] (c_l) {};
    \node[circle, draw, minimum size=1cm, above right=1cm and 0.5cm of c_root] (c_r) {};

    \draw[->] (c_root) -- (c_l) node[midway, anchor=south east, align=right, xshift=1mm, yshift=-5mm] {Get};
    \draw[->] (c_root) -- (c_r) node[midway, anchor=south west, xshift=-1mm, yshift=-5mm] {Inc};


\end{tikzpicture}
\end{document}