Linked List Cycle

Statement

Given the head of a linked list, determine whether the list contains a cycle. A cycle exists if a node in the list can be revisited by continuously following the next pointers. Return TRUE if a cycle is present; otherwise, return FALSE.

Constraints:

Let n be the number of nodes in a linked list.

• $0\leq$ n $\leq500$
• $-10^5 \leq$ Node.value $\leq 10^5$

Examples