
#include<iostream>
#include <list>
#include <stack>
using namespace std;
 

class Graph
{
    int V;    
 
    
    list<int> *adj;
 
    
    void topologicalSortUtil(int v, bool visited[], stack<int> &Stack);
public:
    Graph(int V);   
 
     
    void addEdge(int v, int w);
 
    
    void topologicalSort();
};
 
Graph::Graph(int V)
{
    this->V = V;
    adj = new list<int>[V];
}
 
void Graph::addEdge(int v, int w)
{
    adj[v].push_back(w); 
}
 

void Graph::topologicalSortUtil(int v, bool visited[], stack<int> &Stack)
{
    
    visited[v] = true;
 
    
    list<int>::iterator i;
    for (i = adj[v].begin(); i != adj[v].end(); ++i)
        if (!visited[*i])
            topologicalSortUtil(*i, visited, Stack);
 
    
    Stack.push(v);
}
 

void Graph::topologicalSort()
{
    stack<int> Stack;
 
    
    bool *visited = new bool[V];
    for (int i = 0; i < V; i++)
        visited[i] = false;
 
    
    
    for (int i = 0; i < V; i++)
      if (visited[i] == false)
        topologicalSortUtil(i, visited, Stack);
 
    
    while (Stack.empty() == false)
    {
        cout << Stack.top() << " ";
        Stack.pop();
    }
}
 

int main()
{
    
    Graph g(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);
 
    cout << "Following is a Topological Sort of the given graph \n";
    g.topologicalSort();
 
    return 0;
}
