标签：efi one nod wap ppa leetcode 出错 pre its
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.
key:返回值出错，包括头结点
Python实现:
# 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): if head is None or head.next is None: return head dummy = ListNode(0) dummy.next = head p = dummy while p.next and p.next.next: tmp = p.next.next p.next.next = tmp.next tmp.next = p.next p.next = tmp p = p.next.next return dummy.next
leetcode_024 Swap Nodes in Pairs
标签：efi one nod wap ppa leetcode 出错 pre its
原文地址：http://www.cnblogs.com/ytq1016/p/6868907.html
