说明：  网状结构中寻找最短路线。类似于A算法但不同于A算法。将所记录的步数修改为里程则可用于公路系统自动寻路。计算代码很短，仅二十余行。
(Reticular formation to find the shortest route. A method similar to but different from A algorithms. The recorded number of steps can be used to modify mileage highway system automatically find its way. Calculation code is very short, only more than twenty lines.)