题解 | #反转链表#

#-*- coding:utf-8 -*-
class ListNode:
    def __init__(self, x, next = None):
        self.val = x
        self.next = None
class Solution:
    # 返回ListNode
    def ReverseList(self, pHead):
        # write code here
        pre = None
        while pHead:
            # 先反转pHead.next，然后右移一步更新pre和pHead
            pHead.next, pre, pHead = pre, pHead, pHead.next
        return pre