剑指offer-题16：反转链表

今天药忘吃喽~ 2022-05-30 10:40 170阅读 0赞

## **题目描述** ##

输入一个链表的头结点，反转该链表并输出反转后链表的头结点。

实验平台：[牛客网][Link 1]

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## **解决思路：** ##

![这里写图片描述][70]  
![这里写图片描述][70 1]  
![这里写图片描述][70 2]

java:

/*
    public class ListNode {
        int val;
        ListNode next = null;
    
        ListNode(int val) {
            this.val = val;
        }
    }*/
    public class Solution {
        public ListNode ReverseList(ListNode head) {
            ListNode pNode = head;
            ListNode pPrev = null;
            ListNode pNest = null;
            ListNode pReversedHead = null;
            while (pNode != null) {
                pNest = pNode.next;
                if (pNest == null) {
                    pReversedHead = pNode;
                }
                pNode.next = pPrev;
                pPrev = pNode;
                pNode = pNest;
            }
            return pReversedHead;
        }
    }

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):
            # write code here
            pNode = pHead
            pPrev = None
            pReversedHead = None
            while pNode is not None:
                pNext = pNode.next
                if pNext is None:
                    pReversedHead = pNode
                pNode.next = pPrev
                pPrev = pNode
                pNode = pNext
            return pReversedHead

[Link 1]: https://www.nowcoder.com/ta/coding-interviews?page=1
[70]: /images/20220530/3e06fd2f03224d66a13f6d0591b9fb65.png
[70 1]: /images/20220530/e61d1d14b00841c0ac44d8cb20509d1f.png
[70 2]: /images/20220530/f701af405fcf4df9bd70add2b9bed58f.png