Final answer:
The order of strongly connected components in a directed graph is determined by algorithms like Kosaraju's or Tarjan's, which identifies SCCs based on the nodes' finish times in a DFS.
Step-by-step explanation:
The term strongly connected components (SCCs) refers to subsets of a directed graph where every vertex is reachable from every other vertex within the same subset. To find the order of strongly connected components, one commonly uses an algorithm like Kosaraju's or Tarjan's algorithm.
In Kosaraju's algorithm, the process involves two main phases: First, a depth-first search (DFS) is performed to compute a finishing time for each vertex. Second, the graph is transposed, and another DFS is conducted in the decreasing order of finishing times. This reveals the SCCs in a reverse topological order.
In Tarjan's algorithm, SCCs are found using a single DFS run. During traversal, it maintains a low-link value that helps in identifying SCCs at the point when a back edge to an ancestor is found, or a self-loop is encountered.
Thus, the order of strongly connected components refers to their sequence determined by these algorithms, which is based on the discovery and finish time of the nodes during DFS.