Your question is Reverse a Linked List. Start with the requirements on the right.
Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.
Given the head of a singly linked list, reverse the list and return the new head.
Implement the reversal in-place. You may assume the list nodes are represented by a ListNode object with fields val and next.
head, the head node of a singly linked list, or None for an empty list.def reverse_linked_list(head):