【剑指offer】面试题17—合并两个排序的链表

一、题目描述

输入两个单调递增的链表，输出两个链表合成后的链表，当然我们需要合成后的链表满足单调不减规则。

二、代码实现

# -*- 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):
        # write code here
        if pHead1 == None: return pHead2
        if pHead2 == None: return pHead1
        resHead = resNode = ListNode(-1)
        while pHead1 and pHead2:
            if pHead1.val < pHead2.val:
                resNode.next = pHead1
                pHead1 = pHead1.next
            else:
                resNode.next = pHead2
                pHead2 = pHead2.next
            resNode = resNode.next
        if pHead1: resNode.next = pHead1
        if pHead2: resNode.next = pHead2
        
        return resHead.next