答案1
% arara: pdflatex
\documentclass{article}
\usepackage{tikz-cd}
\begin{document}
\[
\begin{tikzcd}[%
,every cell/.append style={align=center}
,every arrow/.append style={Rightarrow}
]
(B)\drar & & & & (HK)\\
& (RL)\rar & (BR)\rar & (M)\urar\drar & \\
(R)\urar & & & & (P)
\end{tikzcd}
\]
\end{document}