题解 | 两两交换链表的节点

# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param head ListNode类 
# @return ListNode类
#
class Solution:
    def swapLinkedPair(self , head: ListNode) -> ListNode:
        # write code here
        dummy = ListNode(0)
        dummy.next = head
        cur, head = head, dummy
        while cur and cur.next:
            tmp = cur.next.next
            head.next, head.next.next, head, cur.next, cur = cur.next, cur, cur, tmp, tmp#注意节点交换顺序
        return dummy.next