首页 > 代码库 > Swap Nodes in Pairs
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 values in the list, only nodes itself can be changed.
答案
/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { * val = x; * next = null; * } * } */ public class Solution { public ListNode swapPairs(ListNode head) { if(head==null||head.next==null) { return head; } ListNode pHead=new ListNode(0); ListNode p; ListNode first; ListNode second; ListNode pFirst; ListNode pSecond; pHead.next=head; first=head; pFirst=first; second=first.next; pSecond=first.next; for(p=pSecond.next;p!=null;) { pFirst.next=p; pFirst=p; p=p.next; if(p!=null) { pSecond.next=p; pSecond=p; p=p.next; } else { break; } } if(pFirst.next!=null) { pFirst.next=null; } if(pSecond.next!=null) { pSecond.next=null; } pFirst=first; pSecond=second; for(p=pHead;pSecond!=null;) { p.next=pSecond; pSecond=pSecond.next; p=p.next; if(p!=null) { p.next=pFirst; pFirst=pFirst.next; p=p.next; } } return pHead.next; } }
Swap Nodes in Pairs
声明:以上内容来自用户投稿及互联网公开渠道收集整理发布,本网站不拥有所有权,未作人工编辑处理,也不承担相关法律责任,若内容有误或涉及侵权可进行投诉: 投诉/举报 工作人员会在5个工作日内联系你,一经查实,本站将立刻删除涉嫌侵权内容。