【LeetCode】剑指 Offer II 024. 反转链表

1. 题目

2. 分析

思路一定要清晰，思路一定要清晰。

3. 代码

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def reverseList(self, head: ListNode) -> ListNode:
        start = head
        
        pre = None # 初始节点为None
        # 开始翻转
        while(head):
            nx = head.next
            head.next = pre
            pre = head
            head = nx
        return