Strongly Connected Components
A strongly connected component, or SCC, of a directed graph is a maximal set of vertices where every vertex can reach every other vertex. Kosaraju's algorithm uses two DFS passes, one on the original graph and one on the transposed graph. Tarjan's algorithm finds SCCs in one DFS using discovery times and low-link values.
SCCs apply to directed graphs.
Kosaraju uses two DFS traversals.
Tarjan uses one DFS.
Both run in O(V+E).
SCCs are useful in dependency analysis, graph condensation, and reachability problems.