[Python刷题记录]-两两交换链表中的节点-链表-中等

链接：24. 两两交换链表中的节点 - 力扣（LeetCode）

直接写

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution(object):
    def swapPairs(self, head):
        """
        :type head: Optional[ListNode]
        :rtype: Optional[ListNode]
        """
        if head == None or head.next ==None:
            return head
        lNode = head
        rNode = head.next
        resNode = rNode
        llNode = lNode
        while lNode and rNode:
            llNode = lNode
            lNode.next = rNode.next
            rNode.next= lNode
            lNode = lNode.next
            if lNode and lNode.next:
                rNode = lNode.next
                lNode.next = rNode
                llNode.next = rNode
            else:
                rNode = None
        return resNode