Rockwell Automation 店面

Given a linked list, how do you determine if a linked list has a cycle?

LC 原题

Initial solution given: Rabbit and hare, 2 pointer technique.

Follow-up #1: Can you provide the runtime/space complexity for the rabbit and hare technique?
Follow-up #2: Can you solve without using the rabbit and hare technique? You cannot modify the nodes. And provide the runtime/space complexity.
Follow-up #3: Which of the two solutions you presented is best? 2 Pointer technique vs HashTable technique