7-3 两个有序链表序列的合并 用python

可以使用归并排序的思想来合并两个有序链表。

以下是 Python 代码示例：

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

class Solution:
    def mergeTwoLists(self, l1: ListNode, l2: ListNode) -> ListNode:
        # 创建一个哨兵结点
        dummy = ListNode(0)
        curr = dummy

        # 遍历两个链表，比较每个结点的值
        while l1 and l2:
            if l1.val <= l2.val:
                curr.next = l1
                l1 = l1.next
            else:
                curr.next = l2
                l2 = l2.next
            curr = curr.next

        # 将剩余的结点连接上
        curr.next = l1 or l2

        # 返回合并后的链表
        return dummy.next

你也可以使用递归的方法来实现。

class Solution:
    def mergeTwoLists(self, l1: ListNode, l2: ListNode) -> ListNode:
        if not l1:
            return l2
        if not l2:
            return l1
        if l1.val <= l2.val:
            l1.next = self.mergeTwoLists(l1.next, l2)
            return l1
        else:
            l2.next = self.mergeTwoLists(l1, l2.next)
            return l2

希望能够帮到你！