说明：  Dijkstra算法是典型最短路算法，用于计算一个节点到其他所有节点的最短路径。主要特点是以起始点为中心向外层层扩展，直到扩展到终点为止。Dijkstra算法能得出最短路径的最优解，但由于它遍历计算的节点很多，所以效率低。
(Dijkstra algorithm is a typical shortest path algorithm, used to calculate a node to all other nodes of the shortest path. The main characteristics is the starting point as the center outward expansion layers, until the end date be extended to. Dijkstra shortest path algorithm can arrive at the optimal solution, but because of its calculation of the node traversal, so inefficient.)