拓扑排序，简单地说，是由某个集合上的一个偏序得到该集合上的一个全序，这个操作称之为拓扑排序。一个表示偏序的有向图可用来表示一个流程图。它或者是一个施工流程图，或者是一个产品生产的流程图，再或是一个数据流图（每个顶点表示一个过程）。图中每一条有向边表示两个子工程之间的次序关系（领先关系）。-Topological sort, simply put, is a collection from a poset to be the collection of a total order, the operation known as topological sorting. That the poset of a directed graph can be used to represent a flow chart. It is a construction or flow chart, or is a production flow chart, and then or a data flow diagram (a process that each vertex). Map to the side of each of two sub-projects that the order of relations between the (leading relations).