class Solution:
    def hasCycle(self, head: ListNode) -> bool:
        """
	Given head, the head of a linked list, determine if the linked list has a cycle in it.

	There is a cycle in a linked list if there is some node in the list that can be reached 
	again by continuously following the next pointer. Internally, pos is used to denote the 
	index of the node that tail's next pointer is connected to.
	Note that pos is not passed as a parameter.

	Return true if there is a cycle in the linked list. Otherwise, return false
	"""
        
        fast = head
        slow = fast
        
        while fast and fast.next:
            fast = fast.next.next
            slow = slow.next
            
            if fast==slow:
                return True
        else:
            return False

class Solution:
    def hasCycle(self, head: ListNode) -> bool:
        """
	Given head, the head of a linked list, determine if the linked list has a cycle in it.

	There is a cycle in a linked list if there is some node in the list that can be reached 
	again by continuously following the next pointer. Internally, pos is used to denote the 
	index of the node that tail's next pointer is connected to.
	Note that pos is not passed as a parameter.

	Return true if there is a cycle in the linked list. Otherwise, return false
	"""
        
        fast = head
        slow = fast
        
        while fast and fast.next:
            fast = fast.next.next
            slow = slow.next
            
            if fast==slow:
                return True
        else:
            return False

Given head, the head of a linked list, determine if the linked list has a cycle in it.  	There is a cycle in a linked list if there is some node in the list that can be reached  	again by continuously following the next pointer. Internally, pos is used to denote the  	index of the node that tail's next pointer is connected to. 	Note that pos is not passed as a parameter.  	Return true if there is a cycle in the linked list. Otherwise, return false