题解 | #合并两个排序的链表#

# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param pHead1 ListNode类 
# @param pHead2 ListNode类 
# @return ListNode类
#
class Solution:
    def Merge(self , pHead1: ListNode, pHead2: ListNode) -> ListNode:
        # write code here
        if not pHead1:
            return pHead2
        if not pHead2:
            return pHead1
        result = ListNode(-1)
        cur = result
        while pHead1 and pHead2:
            if pHead1.val < pHead2.val:
                cur.next = pHead1
                pHead1 = pHead1.next
            else:
                cur.next = pHead2
                pHead2 = pHead2.next
            cur = cur.next
        cur.next = pHead1 if pHead1 else pHead2
        return result.next

参考大神的代码，几个注意点：

1、没有值时的判断

2、建一个起始节点，方便返回值

3、记得拼接未对比的剩余链表

4、注意移动当前节点