python-leetcode面试题解之第24题两两交换链表中的节点-python题解.zip

# 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 # """ class Solution(object): # def swapPairs(self, head): # current = last = last2 = head # while current is not None: # nex = current.next # if current == last.next: # last.next = nex # current.next = last # if last == head: # head = current # else: # last2.next = current # last2 = last # last = nex # current = nex # return head def swapPairs(self, head): dummyHead = ListNode(-1) dummyHead.next = head prev, p = dummyHead, head while p != None and p.next != None: q, r = p.next, p.next.next prev.next = q q.next = p p.next = r prev = p p = r return dummyHead.next