Graph.java (topological_sort)

/*
 *
 * @author shivam
 */
import java.util.*;
class Graph{
   public int v;
    public LinkedList<Integer> array[];  //array 
    
    Graph(int v)
    {
        System.out.println("const");
       int V=v ;
      array = new LinkedList[V]; 
        for(int i=0;i<V;i++)
        {
            array[i]= new LinkedList<Integer>(V);
        }
    }
   void addEdge(int src,int dest)
   {
       array[src].addLast(dest);
   }

   public  void topological_sort_untill(int v,boolean visited[],Stack stack)
 {
   visited[v]=true;
   Iterator<Integer> itr = array[v].iterator();
   while(itr.next()!=null)
   {
      int i=itr.next();
      topological_sort_untill(i,visited,stack); 
   }
   stack.push(v);
 } 
   
public  void topological_sort()
 {
   Stack stack= new Stack();
   boolean visited[]= new boolean[v];
   for(int i=0;i<v;i++)
       visited[i]=false;
   
   for(int i=0;i<v;i++)
   {
     if(visited[i]==false)
     {
         topological_sort_untill(i,visited,stack);
     }
   }
  while(!stack.isEmpty())
         System.out.println(stack.pop()+"->");
 }


    public static void main(String[] args) {
        int no_of_vertex=5;
        Graph graph= new Graph(no_of_vertex);
        System.out.println("hello main");
      try{  graph.addEdge(5, 2);
        graph.addEdge(5, 0);
        graph.addEdge(4, 0);
        graph.addEdge(4, 1);
        graph.addEdge(2, 3);
        graph.addEdge(3, 1);
        graph.topological_sort();
      }catch(Exception e)
      {
          System.out.println("e.printStackTrace()");
      }
      }
}