12-206. Reverse Linked List
题目描述：
Reverse a singly linked list.
Example:
Input: 1->2->3->4->5->NULL Output: 5->4->3->2->1->NULL
Follow up:
A linked list can be reversed either iteratively or recursively. Could you implement both?
代码实现：
1 # Definition for singly-linked list. 2 # class ListNode: 3 # def __init__(self, x): 4 # self.val = x 5 # self.next = None 6 7 class Solution: 8 def reverseList(self, head: ListNode) -> ListNode: 9 prev = None 10 while head: 11 curr = head 12 head = head.next 13 curr.next = prev 14 prev = curr 15 return prev
