剑指offer-题17：合并两个排序的链表

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。

实验平台：牛客网

---

解决思路：

java:

/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode Merge(ListNode list1,ListNode list2) {
        if(list1 == null){
            return list2;
        }else if (list2 == null) {
            return list1;
        }

        ListNode newNode = null; 

        if(list1.val < list2.val){
            newNode = list1;
            newNode.next = Merge(list1.next, list2);
        }else {
            newNode = list2;
            newNode.next = Merge(list1, list2.next);
        }
        return newNode;
    }
}

python:

# -*- 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 is None:
            return pHead2
        elif pHead2 is None:
            return pHead1

        if pHead1.val < pHead2.val:
            node = pHead1
            node.next = self.Merge(pHead1.next, pHead2)
        else:
            node = pHead2
            node.next = self.Merge(pHead1, pHead2.next)
        return node