剑指Offer - 15 - 反转链表

题目描述

反转链表

输入一个链表，反转链表后，输出新链表的表头。

思路

用一个指针来保存链表倒序，遍历一次链表，每获取一个节点就把该节点加到新链表的表头，再让指针指向表头，如此反复直到遍历结束即可。

Code

• Python

# -*- coding:utf-8 -*-
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
class Solution:
    # 返回ListNode
    def ReverseList(self, pHead):
      p = pHead
      q = None
      while p is not None:
        n = p
        p = p.next
        n.next = q
        q = n
      return q

• JavaScript

/*function ListNode(x){
    this.val = x;
    this.next = null;
}*/
function ReverseList(pHead)
{
  let p = pHead
  let q = null
  while(p) {
    let n = p
    p = p.next
    n.next = q
    q = n
  }
  return q
}