# [[linked-list|Linked List]] Cycle
## Solution 1: Hash Table
```python
table = set()
curr = head
while curr:
if curr in table:
return True
table.add(curr)
curr = curr.next
return False
```
## Solution 2: Floyd's Cycle Finding Algorithm
Utilizes [[fast-and-slow-pointer]].
```python
if head is None:
return False
slow = head
fast = head.next
while slow != fast:
if fast is None or fast.next is None:
return False
slow = slow.next
fast = fast.next.next
return True
```