141. Linked List Cycle Detection

/**
 * Definition for singly-linked list.
 * class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public boolean hasCycle(ListNode head)
     {
        if(head == null || head.next==null)
        return false;

    ListNode slow = head ;
    ListNode fast = head;
    while(fast != null && fast.next != null)
    {
        slow = slow.next;
            fast = fast.next.next;

            if (slow == fast) {
                return true;
            }
        }

        return false;


        
    }
}