有向图:一种图(graph)结构,由顶点(vertices/nodes)和有方向的边(directed edges/arcs)组成;每条边都有从一个顶点指向另一个顶点的方向,记作 u → v。常用于表示“关系具有方向性”的系统,如网页链接、关注关系、任务依赖、交通路线等。(另有相关概念:无向图 undirected graph。)
/dəˈrɛktɪd ɡræf/
A directed graph can model who follows whom on social media.
有向图可以用来建模社交媒体上“谁关注谁”的关系。
In a directed graph, a path from A to B does not necessarily imply a path from B to A, which is why it is useful for representing prerequisites and dependencies.
在有向图中,从 A 到 B 的路径并不一定意味着从 B 到 A 也有路径,因此它适合用来表示先修条件与依赖关系。
directed 来自拉丁语 dirigere(“引导、指向”),强调“带方向”;graph 源自希腊语 graphein(“书写、描画”),在数学中引申为“用点和线来表示关系的结构”。合起来 directed graph 就是“带方向的关系图”。