1 # Definition for singly-linked list. 2 # class ListNode: 3 # def __init__(self, x): 4 # self.val = x 5 # self.next = None 6 7 class Solution: 8 def swapPairs(self, head: ListNode) -> ListNode: 9 node = ListNode(-1) 10 node.next = head 11 pre = node 12 while pre.next != None and pre.next.next != None: 13 l1,l2 = pre.next,pre.next.next 14 nexNode = l2.next 15 l1.next = nexNode 16 l2.next = l1 17 pre.next = l2 18 pre = l1 19 return node.next
交换链表中相邻的两个节点，注意12行的判断条件。
