import java.io.*;
import java.util.*;
// This class represents a directed graph using adjacency
// list representation
class Graph
{
private int V; // No. of vertices
private LinkedList adj[]; // Adjacency List
//Constructor
Graph(int v)
{
V = v;
adj = new LinkedList[v];
for (int i=0; i it = adj[v].iterator();
while (it.hasNext())
{
i = it.next();
if (!visited[i])
topologicalSortUtil(i, visited, stack);
}
// Push current vertex to stack which stores result
stack.push(new Integer(v));
}
// The function to do Topological Sort. It uses
// recursive topologicalSortUtil()
void topologicalSort()
{
Stack stack = new Stack();
// Mark all the vertices as not visited
boolean visited[] = new boolean[V];
for (int i = 0; i < V; i++)
visited[i] = false;
// Call the recursive helper function to store
// Topological Sort starting from all vertices
// one by one
for (int i = 0; i < V; i++)
if (visited[i] == false)
topologicalSortUtil(i, visited, stack);
// Print contents of stack
while (stack.empty()==false)
System.out.print(stack.pop() + " ");
}
// Driver method
public static void main(String args[])
{
// Create a graph given in the above diagram
Graph g = new Graph(6);
g.addEdge(5, 2);
g.addEdge(5, 0);
g.addEdge(4, 0);
g.addEdge(4, 1);
g.addEdge(2, 3);
g.addEdge(3, 1);
System.out.println("Following is a Topological " +
"sort of the given graph");
g.topologicalSort();
}
}