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:
		# 没什么好说的，就是在两个链表上分别设置两个指针，从头访问到尾，依次添加较小的节点
        if pHead1 == None:
            return pHead2
        if pHead2 == None:
            return pHead1
        
        if pHead1.val <= pHead2.val:
            head = pHead1
            pHead1 = pHead1.next
        else:
            head = pHead2
            pHead2 = pHead2.next
        node = head
        
        while pHead1 != None and pHead2 != None:
            if pHead1.val < pHead2.val:
                head.next = pHead1
                pHead1 = pHead1.next
            else:
                head.next = pHead2
                pHead2 = pHead2.next
            head = head.next
        
        if pHead1 == None:
            head.next = pHead2
        elif pHead2 == None:
            head.next = pHead1
        return node