我有一个依赖图,其中一个节点需要满足前一个节点的两个副本.我想使用拓扑排序来获得评估顺序,但问题是拓扑排序忽略了并行/多边,并将其视为一个依赖.我在做错事情,或者我是否需要一个适用于多图的特定toposort？ 最佳答案 可以通过修改拓扑排序算法来完成.

原始算法存储没有入边(S)的所有节点的集合,主要步骤是从S取一个节点,从S中移除它,并从图中移除所有边缘并检查是否有其他节点没有入边.

将其更改为：从S获取一个节点,将一个边缘实例移除到每个邻居,如果节点没有传出边缘从S中删除它,请检查是否有其他节点没有传入边缘.

Wikipedia的原始代码：

L ← Empty list that will contain the sorted elements
S ← Set of all nodes with no incoming edges
while S is non-empty do
    remove a node n from S
    add n to tail of L
    for each node m with an edge e from n to m do
        remove edge e from the graph
        if m has no other incoming edges then
            insert m into S

改变算法：

L ← Empty list that will contain the sorted elements
S ← Set of all nodes with no incoming edges
while S is non-empty do
    take a node n from S
    add n to tail of L
    for each neighbouring node m of n
        remove ONE edge (m,n) from the graph
        if m has no other incoming edges then
            insert m into S
    if n doesn't have outgoing edges
       remove n from S