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 trueif there is a cycle in the linked list. Otherwise, return false.
from leetcode_py import ListNodeclass Solution: # Time: O(n) # Space: O(1) def has_cycle(self, head: ListNode[int] | None) -> bool: fast = head slow = head while fast and fast.next: assert slow is not None fast = fast.next.next slow = slow.next if fast is slow: return True return False
