Dijkstra

代码说明：

  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' s algorithm is a typical shortest path algorithm used to calculate a node to all other nodes of the shortest path. Main features is the starting point for the center layers expand outward until the end date extended to)