题解 | #合并两个排序的链表#

# -*- coding:utf-8 -*-
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
class Solution:
    # 返回合并后列表
    def Merge(self, pHead1, pHead2):
        #递归法，用三个指针，不断判断MergedHead.next是哪一个
        if pHead1==None:
            return pHead2
        elif pHead2==None:
            return pHead1
        
        MergedHead=None
        if pHead1.val<pHead2.val:
            MergedHead=pHead1
            MergedHead.next=self.Merge(pHead1.next, pHead2)
        else:
            MergedHead=pHead2
            MergedHead.next=self.Merge(pHead1, pHead2.next)
        return MergedHead