题意:给一个单链表,将其每两个结点交换,只改尾指针,不改元素值. 思路:迭代法和递归法都容易写,就写个递归的了. 4ms /** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode* swapPairs(List…

Swap Nodes in Pairs: Given a linked list, swap every two adjacent nodes and return its head. For example, Given 1->2->3->4, you should return the list as 2->1->4->3. Your algorithm should use only constant space. You may not modify the v…

Swap Nodes in Pairs Given a linked list, swap every two adjacent nodes and return its head. For example,Given 1->2->3->4, you should return the list as 2->1->4->3. Your algorithm should use only constant space. You may not modify the val…

Given a linked list, swap every two adjacent nodes and return its head. For example,Given1->2->3->4, you should return the list as2->1->4->3. Your algorithm should use only constant space. You may not modify the values in the list, only…

给定一个链表,对每两个相邻的结点作交换并返回头节点.例如:给定 1->2->3->4,你应该返回 2->1->4->3.你的算法应该只使用额外的常数空间.不要修改列表中的值,只有节点本身可以​​更改. 详见:https://leetcode.com/problems/swap-nodes-in-pairs/description/ 实现语言:Java 方法一: /** * Definition for singly-linked list. * public class…

Given a linked list, swap every two adjacent nodes and return its head. For example, Given 1->2->3->4, you should return the list as 2->1->4->3. Your algorithm should use only constant space. You may not modify the values in the list, on…

Given a linked list, swap every two adjacent nodes and return its head.For example,Given 1->2->3->4, you should return the list as 2->1->4->3.Your algorithm should use only constant space. You may not modify the values in the list, only…

感觉这个题后台的运行程序有问题,一开始自己想的是反转链表那道题的方法,只是隔一个节点执行一次,但是没有通过,TLE了,但是很奇怪,并没有死循环,就是最后返回的时候超时. 最后的思路就是很简单的进行交换,设置一个头结点前边的0节点先把第三个节点接到第一个上边,然后把第一个接到第二个上,然后把第二个节点接到0节点上,然后把当前节点设置成第一个节点(现在是第二个,而且是下次交换的0节点) public ListNode swapPairs(ListNode head) { if (head==null…

Given a linked list, swap every two adjacent nodes and return its head. For example,Given 1->2->3->4, you should return the list as 2->1->4->3. Your algorithm should use only constant space. You may not modify the values in the list, onl…

1.题目描述 Given a linked list, swap every two adjacent nodes and return its head.   For example, Given 1->2->3->4, you should return the list as 2->1->4->3.   Your algorithm should use only constant space. You may not modify the values in t…