DirectedDFS.java

import edu.princeton.cs.algs4.*;

public class DirectedDFS{
	private boolean[] marked;
	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]));
		Bag<Integer> sources = new Bag<>();
		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.print(v + " ");
		} 
		StdOut.println();
	}


}