题解 | #反转链表# #链表#

#coding:utf-8
# 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 ):
        # write code here
        if head == None:
            return head
        prev = None
        node = head
        while node != None:
            next = node.next
            node.next = prev
            prev = node
            node = next
        return prev