Solution: Topological Sorting of a Graph

class Sort {
 public static void utilityFunction(Graph g, int v, boolean visited[], Stack < Integer > myStack) {
  // Mark the current node v as visited. 
  visited[v] = true;
  // traverse all the vertices adjacent to this 
  // vertex and do a recursive call to the utility function for these
  Iterator < Integer > i = g.getAdj()[v].iterator();
  Integer temp;
  while (i.hasNext()) {
   
   temp = i.next();
   if (!visited[temp])
    utilityFunction(g, temp, visited, myStack);
  }
  // Push current vertex in to the stack 
  myStack.push(v);
 }
 @SuppressWarnings("unchecked")
 public static void topologicalSort(Graph g) {
  Stack < Integer > myStack = new Stack();
  // all the vertices marked as not visited by default
  int numofVertices = g.getVertices();
  boolean visited[] = new boolean[numofVertices];
  // Call the utility function for 
  // Topological Sort from all vertices 
  for (int i = 0; i < numofVertices; i++) {
   if (visited[i] == false) {
    utilityFunction(g, i, visited, myStack);
   }
  }
  //print the contents of the stack           
  while (myStack.empty() == false) {
   System.out.print(myStack.pop() + " ");
  }
 }
}
class Main {
 public static void main(String args[]) {
  Graph g = new Graph(6);
  g.addEdge(5, 0);
  g.addEdge(5, 2);
  g.addEdge(4, 2);
  g.addEdge(4, 1);
  g.addEdge(2, 3);
  g.addEdge(3, 1);
  System.out.println("Graph1 Topological Sort: ");
  Sort.topologicalSort(g);
  System.out.println();
  Graph g1 = new Graph(5);
  g1.addEdge(0, 1);
  g1.addEdge(1, 2);
  g1.addEdge(2, 3);
  g1.addEdge(2, 4);
  g1.addEdge(3, 4);
  g1.addEdge(0, 3);
  System.out.println("Graph2 Topological Sort: ");
  Sort.topologicalSort(g1);
 }
}