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
        dummy_head = ListNode(-1)
        cur = dummy_head

        while pHead1 is not None or pHead2 is not None:
            if pHead1 is None:
                cur.next = pHead2
                pHead2 = pHead2.next
            elif pHead2 is None:
                cur.next = pHead1
                pHead1 = pHead1.next
            else:
                val1, val2 = pHead1.val, pHead2.val
                if val1 < val2:
                    cur.next = pHead1
                    pHead1 = pHead1.next
                else:
                    cur.next = pHead2
                    pHead2 = pHead2.next
            cur = cur.next

        return dummy_head.next

分别判断两个指针的值是否为空，如果为空直接连到另一个不为空的指针上，都不为空时对值进行比较。