Strongly Connected Components

Problem
Find all strongly connected components (SCCs) of a directed graph — maximal node sets where every node reaches every other.

Input / Output

• Input: n nodes, directed edge list. Output: the SCCs (list of node groups).

Constraints

• Up to 10^5 nodes/edges; O(V + E) expected.

Example

• Edges 0→1, 1→2, 2→0, 1→3 → SCCs {0,1,2} and {3}.