/*

* Sample usage: java DirectedDFS tinyDG.txt 1

* Sample usage: java DirectedDFS tinyDG.txt 2

* Sample usage: java DirectedDFS tinyDG.txt 1 2 6

*/

public class DirectedDFS {

private boolean[] marked; // marked[v] = is there a s-v path?

public DirectedDFS(Digraph G, int s){

marked = new boolean[G.V()];

dfs(G, s);

}

public DirectedDFS(Digraph G, Iterable<Integer> sources){

marked = new boolean[G.V()];

for (int s: sources)

if (!marked[s])

dfs(G, s);

}

private void dfs(Digraph G, int v){

marked[v] = true;

for (int w : G.adj(v))

if (!marked[w])

dfs(G, w);

}

public boolean marked(int w){

return marked[w];

}

public static void main(String[] args){

Digraph G = new Digraph(new In(args[0]));

LinkedBag<Integer> sources = new LinkedBag<>();

for (int i=1; i<args.length; i++)

sources.add(Integer.parseInt(args[i]));

DirectedDFS reachable = new DirectedDFS(G, sources);

for (int v=0; v<G.V(); v++)

if (reachable.marked(v))

StdOut.println(v + " ");

StdOut.println();

}

}