include graphics

graphics.tex

\begin{figure}[htbp]
\begin{minipage}[b]{0.5\linewidth}
\label{SzvsT}
\centering
\includegraphics[width=\textwidth]{fig/SzvsT.pdf}
\caption{initial node set size $|V_Q|$ versus runing time}
\end{minipage}
\vspace{0.5cm}
\begin{minipage}[b]{0.5\linewidth}
\label{RvsTime}
\centering
\includegraphics[width=\textwidth]{fig/RvsTime.pdf}
\caption{the radius versus the running time}
\end{minipage}
\end{figure}