leetcode——21. 合并两个有序链表

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def mergeTwoLists(self, l1: ListNode, l2: ListNode) -> ListNode:
        p=rst=ListNode(0)
        while True:
            try:
                while l1.val<=l2.val:
                    p.next=l1
                    l1,p=l1.next,p.next
                while l1.val>l2.val:
                    p.next=l2
                    l2,p=l2.next,p.next
            except:break
        p.next=l1 or l2
        return rst.next