/*

* Sample usage: java CC tinyG.txt

* Sample usage: java CC mediumG.txt

*/

public class CC {

private boolean[] marked;

private int[] id; // id[v] = id of connected component containing v

private int count; // number of connected components

public CC(Graph G){

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

id = new int[G.V()];

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

if (!marked(s)){

dfs(G, s);

count++;

}

}

private void dfs(Graph G, int v){

marked[v] = true;

id[v] = count;

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

if (!marked[w])

dfs(G, w);

}

public boolean marked(int w){

return marked[w];

}

public int count(){

return count;

}

public boolean connected(int w, int v){

return id[w]==id[v];

}

public int id(int v){

return id[v];

}

public static void main(String[] args){

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

CC cc = new CC(G);

int M = cc.count();

StdOut.println(M + " components");

LinkedBag<Integer>[] components;

components = (LinkedBag[]) new LinkedBag[M];

for (int i=0; i<M; i++)

components[i] = new LinkedBag<Integer>();

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

components[cc.id(v)].add(v);

for (int i=0; i<M; i++){

for (int v: components[i])

StdOut.print(v + " ");

StdOut.println();

}

}

}