def test():
head = ListNode.build(5)
print("original list")
ListNode.show(head)
print("reversed list by single assignment")
ListNode.show(reverseSingle(head))
head = ListNode.build(5)
print("reversed list by tuple assignment")
ListNode.show(reverseTuple(head))
return True
else:
tempSet.add(head.next)
head = head.next
return False
"""
Runtime: 56 ms, faster than 51.53% of Python3 online submissions for Linked List Cycle.
Memory Usage: 17.6 MB, less than 75.05% of Python3 online submissions for Linked List Cycle.
"""
def hasCycleByFastSlowPointer(self, head: ListNode) -> bool:
if (not (head and head.next)):
return False
slow = fast = head
while (slow and fast and fast.next):
slow = slow.next
fast = fast.next.next
if (slow is fast):
return True
return False
if __name__ == '__main__':
head = ListNode.build(2)
solution = Solution()
result = solution.hasCycleByFastSlowPointer(head)
print(result)