Check if a linked list is Circular Linked List

PROBLEM :

Given a singly linked list, find if the linked list is circular or not.  A linked list is called circular if it not NULL terminated and all nodes are connected in the form of a cycle.   An empty linked list is considered as circular.

Note  that this problem is different from cycle detection problem, here all nodes have to be part of cycle.

Input:



You have to complete the method which takes one argument: the head of the linked list. You should not read any input from stdin/console.
The struct Node has a data part which stores the data and a next pointer which points to the next element of the linked list.
There are multiple test cases. For each test case, this method will be called individually.

Output:
The function should return true if the given linked list is circular, else false.

Constraints:
1 <=T<= 50
1 <=N<= 100
1 <=value<= 1000

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SIMPLE c++ IMPLEMENTATION :
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/* Link list Node
struct Node {
    int data;
    struct Node* next;
}; */


/* Should return true if linked list is circular, else false */
bool isCircular(struct Node *head)
{
   if(head==NULL||head->next==head)
   return true ;
 
   struct Node *temp ,*ptr,*p ;
   p=head ;
   temp=head ;
   ptr=head->next  ;
 
   while(ptr->next!=NULL&&ptr->next->next!=NULL)
   {
       ptr=ptr->next->next ;
       p=p->next ;
     
       if(ptr==temp||ptr->next==temp)
        return true ;
       
        if(ptr==p||ptr->next==p)
        return false ;
     
   }
   return false ;
}


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