标签：des style blog class code java
Link: http://oj.leetcode.com/problems/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.
1 /** 2 * Definition for singly-linked list. 3 * public class ListNode { 4 * int val; 5 * ListNode next; 6 * ListNode(int x) { 7 * val = x; 8 * next = null; 9 * } 10 * } 11 */ 12 public class Solution { 13 public ListNode swapPairs(ListNode head) { 14 if (head == null || head.next == null) 15 return head; 16 ListNode pre = new ListNode(0); 17 pre.next = head; 18 head = pre; 19 ListNode cur = pre.next, post = cur.next; 20 while (post != null) { 21 ListNode temp = post.next; 22 post.next = cur; 23 cur.next = temp; 24 pre.next = post; 25 pre = cur; 26 cur = temp; 27 post = temp; 28 if (cur != null) 29 post = cur.next; 30 } 31 return head.next; 32 } 33 }
For the basic idea, please refer to http://www.cnblogs.com/Altaszzz/p/3704780.html
Swap Nodes in Pairs,布布扣,bubuko.com
标签：des style blog class code java
原文地址：http://www.cnblogs.com/Altaszzz/p/3704787.html
