Does Tarjan's SCC algorithm give a topological sort of the SCC?

Question

I\'ve been studying SCC and algorithms about them, and I\'ve seen that people almost always mention that Kosaraju\'s algorithm finds the SCC and also gives them ordered in a (re

Answer 1

Yes. As Tarjan is based on Depth First Search all you have to do is to add the vertexes to the top of a list when each vertex reach the "closed" state.(ie. its dfs/tarjan call ends for that vertex)

Here is a C/C++/Pseudo-Code example:

void tarjan(int u) {
    visited[u] = true;
    closed[u] = false;
    //dfs + tarjan processing
    for (vi v = G[u].begin(); v != G[u].end(); v++) {
        if (!visited[*v]) {
            dfs(*v);
        } else if (!closed[*v]) {
            // has Cycle
        }
    }
    closed[u] = true;
    //add u to the top of your list here
}