交换链表中相邻节点,要求不能改变节点的值,只能交换节点本身
示例:
输入:2->3->4->5
输出:3->2->5->4
python解决方案:
# Definition for singly-linked list. # class ListNode(object): # def __init__(self, x): # self.val = x # self.next = None class Solution(object): def swapPairs(self, head): """ :type head: ListNode :rtype: ListNode """ prev = ListNode(0) p = prev prev.next = head while head and head.next: prev.next,head.next.next,head.next = head.next,head,head.next.next prev,head = head,head.next return p.next