#include<iostream>

#include<list>

#include<limits.h>

using namespace std;

class Graph{

int V; //No of vertices

list<int> *adj; // Pointer to an array containing adjacency list

bool isCyclicUtil(int v,bool visited[],bool*rs);

public:

Graph(int V);

void addEdge(int v,int w);

bool isCyclic();

};

Graph :: Graph(int V){

this->V = V;

adj = new list<int>[V];

}

void Graph :: addEdge(int v,int w){

adj[v].push_back(w);

}

bool Graph :: isCyclicUtil(int v,bool visited[],bool *recStack){

if(visited[v] == false){

visited[v] = true;

recStack[v] = true;

list<int> :: iterator i;

for(i = adj[v].begin(); i!=adj[v].end();i++){

if(!visited[*i] && isCyclicUtil(*i,visited,recStack))

return true;

else if(recStack[*i])

return true;

}

}

recStack[v] = false;

return false;

}

bool Graph :: isCyclic(){

bool *visited = new bool[V];

bool *recStack = new bool[V];

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

visited[i] = false;

recStack[i] = false;

}

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

if(isCyclicUtil(i,visited,recStack))

return true;

return false;

}

int main(){

Graph g(4);

g.addEdge(0,1);

g.addEdge(0,2);

g.addEdge(1,2);

g.addEdge(2,0);

g.addEdge(2,3);

g.addEdge(3,3);

if(g.isCyclic())

cout<<" Graph contains cycle "<<endl;

else

cout<<" Graph doesn't contain cycle"<<endl;

return 0;

}