递归

206. Reverse Linked ListGiven the head of a singly linked list, reverse the list, and return the reversed list. Example 1: 12Input: head = [1,2,3,4,5]Output: [5,4,3,2,1] Example 2: 12Input: head = [1,2]Output: [2,1] Example 3: 12Input: head = []Output: [] Constraints: The number of nodes in the list is the range [0, 5000]. -5000 <= Node.val <= 5000 解法 1：迭代解法123456789101112131415161718192021222324252627/** * Definition for singly-linked list. * struct ListNode { * int...