如何在不使用节点的情况下交替合并链表？通过使用递归呢？

class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next

def mergeLists(l1: ListNode, l2: ListNode) -> ListNode:
    # 边界情况处理
    if not l1:
        return l2
    if not l2:
        return l1
    
    # 创建新节点
    if l1.val < l2.val:
        merged = ListNode(l1.val)
        merged.next = mergeLists(l2, l1.next)
    else:
        merged = ListNode(l2.val)
        merged.next = mergeLists(l1, l2.next)
    
    return merged