The file contains the edges of a directed graph. Vertices are labeled as positive integers from 1 to 875714. Every row indicates an edge, the vertex label in first column is the tail and the vertex label in second column is the head (recall the graph is directed, and the edges are directed from the first column vertex to the second column vertex). So for example, the 11th row looks liks : "2 47646". This just means that the vertex with label 2 has an outgoing edge to the vertex with label 47646.
Compute the strongly connected components (SCCs) on the given graph.
Output: the sizes of the 5 largest SCCs in the given graph, in decreasing order of sizes.
Note that this is a challenging problem, as it requires memory management.
Note that the Depth-first search method in Kosaraju's algorithm are can implemented in an iterative manner or recursive manner. The code here incorporates both approaches.