数据结构——图的基本结构

求给定图中的边（或弧）的数目。

求解出从给定顶点到所有顶点的最短路径（以边数计算）。

判断一个有向图g是否是一棵有向树。（任意一个顶点可能是根）

对给定的图G及出发点，设计算法从出发深度遍历图G，并构造出相应的生成树。 -Data structure- that the basic structure of the given graph edge (or arc) number. Solving out from a given vertex to all vertices of the shortest path (in order to calculate the number of edges). Determine whether a directed graph g is a directed tree. (Any one vertex may be the root) of the given graph G and the starting point, the depth of the design algorithm traverses from the starting graph G, and construct the corresponding spanning tree.