\documentclass[tikz,border=5pt]{standalone}
\usepackage{amsmath,amssymb,tikz}
\begin{document}
\begin{tikzpicture}[scale=1.5, every node/.style={scale=1}]
\draw (0,0) -- (-1,1) -- (-3,1) -- (-4,0) -- (-4,-2) -- (-3,-3) -- (-1,-3) -- (0,0);
\draw (-1,-3) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 7} (-1,-2) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 7, 21} (-1,-1) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 21} (-1,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 20} (-1,1);
\draw (-2,-3) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 4} (-2,-2) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 15} (-2,-1) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 15} (-2,0);
\draw (-3,-3) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 11} (-3,-2) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 11} (-3,-1) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 11} (-3,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt,rotate=-90] {\tiny 11} (-3,1);
\draw (0,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 10} (-1,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 10} (-2,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 10} (-3,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 10} (-4,0);
\draw (-1,-1) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 7} (-2,-1) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 7} (-3,-1) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 7} (-4,-1);
\draw (-1,-2) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 3} (-2,-2) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 3} (-3,-2) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 3} (-4,-2);
\draw (0,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 1} (-1,-2) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 1} (-2,-3);
\draw (0,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 2} (-1,-1) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 2} (-2,-2) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 2} (-3,-3);
\draw (-1,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 23} (-2,-1) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 23} (-3,-2) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 6} (-4,-1);
\draw (-2,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 17} (-3,-1) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 9} (-4,0);
\draw (-1,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 21} (-2,1);
\draw (-1,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 19} (-3,1);
\draw (-2,0) -- node [rectangle,draw,fill=white,sloped,inner sep=1pt] {\tiny 15} (-3,1);
\draw (0,0) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\draw (-1,-3) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\draw (-1,-2) node[circle,draw,fill=white,minimum size=10pt,inner sep=1pt] {\tiny 8};
\draw (-1,-1) node[circle,draw,fill=white,minimum size=10pt,inner sep=1pt] {\tiny 8,22};
\draw (-1,0) node[circle,draw,fill=white,minimum size=10pt,inner sep=1pt] {\tiny 25};
\draw (-1,1) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\draw (-2,-3) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\draw (-2,-2) node[circle,draw,fill=white,minimum size=10pt,inner sep=1pt] {\tiny 5};
\draw (-2,-1) node[circle,draw,fill=white,minimum size=10pt,inner sep=1pt] {\tiny 16,24};
\draw (-2,0) node[circle,draw,fill=white,minimum size=10pt,inner sep=1pt] {\tiny 18};
\draw (-2,1) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\draw (-3,-3) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\draw (-3,-2) node[circle,draw,fill=white,minimum size=10pt,inner sep=1pt] {\tiny 12};
\draw (-3,-1) node[circle,draw,fill=white,minimum size=10pt,inner sep=1pt] {\tiny 13};
\draw (-3,0) node[circle,draw,fill=white,minimum size=10pt,inner sep=1pt] {\tiny 14};
\draw (-3,1) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\draw (-4,-2) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\draw (-4,-1) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\draw (-4,0) node[circle,draw,fill=white,minimum size=5pt,inner sep=1pt] {};
\end{tikzpicture}
\end{document}