\relax \bibstyle{alpha} \bibdata{ref} \@writefile{lof}{\contentsline {figure}{\numberline {1}{\ignorespaces Illustration of sample input. Scheduled trips are depicted in dashed red lines with their respective start times. The optimal solution is to have one driver complete the trip from $2$ to $3$ at time $0$, then travel to location $1$ arriving at time $8$, and then complete the trip from $1$ to $2$. The second driver can complete the trip from $3$ to $4$.\relax }}{2}} \providecommand*\caption@xref[2]{\@setref\relax\@undefined{#1}} \newlabel{fig:sample}{{1}{2}}