求解带可变权值的最短路径问题，如铁路、公路不同的路段组合运输费问题。注：公路的运输费用与路长成正比，铁路的运输费与路段的累积有关-Solving the shortest path variable weight problems, such as railway, road sections of different combination of transportation charges. Note: The cost of road transport and road length i