题目描述
输入一个链表,反转链表后,输出新链表的表头。
# -*- coding:utf-8 -*- class ListNode: def __init__(self, x): self.val = x self.next = None class Solution: # 返回ListNode def ReverseList(self, pHead): # write code here if not pHead or not pHead.next: return pHead last=None while pHead: tmp=pHead.next pHead.next=last last=pHead pHead=tmp return last链接: https://www.nowcoder.com/questionTerminal/75e878df47f24fdc9dc3e400ec6058ca
来源:牛客网
pHead始终指向要反转的结点 last 指向反转后的首结点 每反转一个结点,把pHead结点的下一个结点指向last, last指向pHead成为反转后首结点, 再把pHead向前移动一个结点直至None结束