141_Linked List Cycle

/*
141_Linked List Cycle
Runtime: 0 ms, faster than 100.00% of Java online submissions for Linked List Cycle.
Memory Usage: 40 MB, less than 47.47% of Java online submissions for Linked List Cycle

 */
public class Solution {
    public boolean hasCycle(ListNode head) {
        if(head==null || head.next==null)
            return false; 
        
        ListNode slow=head;
        ListNode fast=head.next;
        
        while(slow!=fast)
        {
            if(fast==null || fast.next==null)
                return false;
            
            slow=slow.next;
            fast=fast.next.next;
            
            
        }
        return true;
        
        
    }
}