题解 | #反转链表# - Python遍历链表同时每个节点完成翻转

# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param head ListNode类 
# @return ListNode类
#
class Solution:
    def ReverseList(self , head: ListNode) -> ListNode:
        # write code here
        if not head:
            return None
        
        p = head
        res = None
        while p:
            temp = p.next
            p.next = res
            res = p
            p = temp

        return res