地铁换乘系统，以北京地铁线路为例，求最少换乘线路，采用深度搜索的方式。-Subway transfer system to the Beijing subway line, for example, seeking a minimum transfer line, using the depth search.

C语言写的地铁模拟收费系统，实现了一些地铁收费的基本功能。-Metro analog toll system written in C language, some of the basic functions of the MTR charges.

在做地铁隧道的断面变形分析时，会用到中轴线的提取-When the subway tunnel section deformation analysis, will be used to extract the axis of