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 and not pHead2:
            return None
        if not pHead1 and pHead2:
            return pHead2
        if not pHead2 and pHead1:
            return pHead1

        if pHead1.val<=pHead2.val:
            rhead,ehead = pHead1,pHead2
        else:
            rhead,ehead = pHead2,pHead1
        res = rhead
        while ehead:
            if (not rhead.next and rhead.val<=ehead.val) or rhead.val<=ehead.val<=rhead.next.val:
                n1 = ehead.next
                ehead.next = rhead.next
                rhead.next = ehead
                ehead = n1
                rhead = rhead.next
            else:
                rhead = rhead.next

        return res