**Reverse Linked List** ===================== ### Problem Statement Given the head of a singly linked list, write a function that reverses the linked list in-place without using any additional memory. ### Rules and Constraints * The function should modify the original linked list. * The function should not use any additional data structures such as arrays, lists, or stacks. * The function should return the head of the reversed linked list. * The input linked list is a singly linked list, meaning each node only points to the next node in the list. * The input linked list may contain circular references and should be ignored during reversal. * The input linked list may have a cycle, and the function should terminate when it encounters a cycle. ### Time and Space Complexity * The time complexity of the function should be O(n), where n is the number of nodes in the linked list. * The space complexity of the function should be O(1), excluding the space required for the input and output linked lists. ### Example **Input:** {"head":[1,2,3,4,5]} **Output:** [5,4,3,2,1]