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 = ListNode(0)  # 虚拟头节点
        cur = dummy          
        # 当两个链表都不为空时
        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  # 移动尾部指针

        if pHead1:
            cur.next = pHead1
        elif pHead2:
            cur.next = pHead2
        
        return dummy.next