p174.java

/*Given head, the head of 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: The linked list does not contains any inner loop.

Example 1:

Input:
LinkedList: 1->2->3->4->5
(the first and last node is connected,
i.e. 5 --> 1)
Output: 1
Example 2:

Input:
LinkedList: 2->4->6->7->5->1
Output: 0
Your Task:
The task is to complete the function isCircular() which checks if the given linked list is circular or not. It should return true or false accordingly. (the driver code prints 1 if the returned values is true, otherwise 0)

Expected Time Complexity: O(N).
Expected Auxiliary Space: O(1).

Constraints:
1 <=Number of nodes<= 100*/

/* Structure of LinkedList
class Node{
	int data;
	Node next;
	Node(int d){
		data = d;
		next = null;
	}
}*/

class GfG{
    boolean isCircular(Node head){
        Node curr=head;
        while(curr!=null){
            curr=curr.next;
            if(curr==head){
                return true;
            }
        }
        return false;
    }
}