#24. 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
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode* swapPairs(ListNode* head) { ListNode* p=head; ListNode* q=p; while(p!=NULL&&p->next!=NULL) { ListNode* newlist=new ListNode(p->val); p->val=p->next->val; newlist->next=p->next->next; p->next=newlist; p=p->next->next; } return q; } };
Leetcode-24 Swap Nodes in Pairs
原文：http://www.cnblogs.com/fengxw/p/6195707.html