Merge Two Sorted Lists leetcode java
题目:
Merge two sorted linked lists and return it as a new list. The new list
should be made by splicing together the nodes of the first two lists.
题解:
这道题是链表操作题,题解方法很直观。
首先,进行边界条件判断,如果任一一个表是空表,就返回另外一个表。
然后,对于新表选取第一个node,选择两个表表头最小的那个作为新表表头,指针后挪。
然后同时遍历两个表,进行拼接。
因为表已经是sorted了,最后把没有遍历完的表接在新表后面。
由于新表也会指针挪动,这里同时需要fakehead帮助记录原始表头。
代码如下:
1 public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
2 if(l1==null)
3 return l2;
4 if(l2==null)
5 return l1;
6
7 ListNode l3;
8 if(l1.val<l2.val){
9 l3 = l1;
l1 = l1.next;
}else{
l3 = l2;
l2 = l2.next;
}
ListNode fakehead = new ListNode(-1);
fakehead.next = l3;
while(l1!=null&&l2!=null){
if(l1.val<l2.val){
l3.next = l1;
l3 = l3.next;
l1 = l1.next;
}else{
l3.next = l2;
l3 = l3.next;
l2 = l2.next;
}
}
if(l1!=null)
l3.next = l1;
if(l2!=null)
l3.next = l2;
return fakehead.next;
}
更简便的方法是,不需要提前选新表表头。
对于新表声明两个表头,一个是fakehead,一个是会挪动的指针,用于拼接。同时,边界条件在后面的补拼中页解决了,所以开头没必要做边界判断,这样代码简化为:
1 public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
2 ListNode fakehead = new ListNode(-1);
3 ListNode l3 = fakehead;
4 while(l1!=null&&l2!=null){
5 if(l1.val<l2.val){
6 l3.next = l1;
7 l3 = l3.next;
8 l1 = l1.next;
9 }else{
l3.next = l2;
l3 = l3.next;
l2 = l2.next;
}
}
if(l1!=null)
l3.next = l1;
if(l2!=null)
l3.next = l2;
return fakehead.next;
}
Merge Two Sorted Lists leetcode java的更多相关文章
- Merge k Sorted Lists Leetcode Java
Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 使 ...
- Merge Two Sorted Lists - LeetCode
目录 题目链接 注意点 解法 小结 题目链接 Merge Two Sorted Lists - LeetCode 注意点 两个链表长度可能不一致 解法 解法一:先比较两个链表长度一致的部分,多余的部分 ...
- 23. Merge k Sorted Lists - LeetCode
Question 23. Merge k Sorted Lists Solution 题目大意:合并链表数组(每个链表中的元素是有序的),要求合并后的链表也是有序的 思路:遍历链表数组,每次取最小节点 ...
- Merge Two Sorted Lists—LeetCode
Merge two sorted linked lists and return it as a new list. The new list should be made by splicing t ...
- Merge k Sorted Lists [LeetCode]
Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. S ...
- 蜗牛慢慢爬 LeetCode 23. Merge k Sorted Lists [Difficulty: Hard]
题目 Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity ...
- Java for LeetCode 023 Merge k Sorted Lists
Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 解 ...
- [LeetCode] Merge Two Sorted Lists 混合插入有序链表
Merge two sorted linked lists and return it as a new list. The new list should be made by splicing t ...
- [LeetCode] 21. Merge Two Sorted Lists 混合插入有序链表
Merge two sorted linked lists and return it as a new list. The new list should be made by splicing t ...
随机推荐
- Windows 中打开 shell
按住 Shift,单机鼠标右键"在当前目录打开命令窗口"
- 1004 Counting Leaves (30)(30 point(s))
problem A family hierarchy is usually presented by a pedigree tree. Your job is to count those famil ...
- python opencv3 圆检测
git:https://github.com/linyi0604/Computer-Vision # coding:utf8 import cv2 import numpy as np img_ori ...
- python装饰器原理
妙处在于装饰器的两个return 1.装饰器 # 使用闭包 def wrap(fun): def check(): print("正在检查用户权限!") fun() return ...
- [BalticOI2002]Bicriterial routing
OJ题号: BZOJ1375.ECNU1468 题目大意: 给定一个无向连通图,每条边有两个权值w1和w2.定义一条路径是优秀的当且仅当没有别的路径满足两个权值的和都比该路径小,求s到t的优秀路径条数 ...
- Linux下rz,sz与ssh的配合使用,实现文件传输
一般来说,linux服务器大多是通过ssh客户端来进行远程的登陆和管理的,使用ssh登陆linux主机以后,如何能够快速的和本地机器进行文件的交互呢,也就是上传和下载文件到服务器和本地: 与ss ...
- bzoj 3211 线段树
开方操作最多进行5次就可以把出现的任何数变成1. 所以用线段树暴力修改,以后修改时只需看一下是否当前区间都是0或1,如果是那么就直接返回. /***************************** ...
- "Blessing of Dimisionality: High Dimensional Feature and Its Efficient Compression for Face Verification"学习笔记
这\(^{[1]}\)是一篇关于如何使用高维度特征在人脸验证中的文章,作者以主要LBP为例子,论述了高维特征和验证性能存在着正相关的关系,即人脸维度越高,验证的准确度就越高.由于那时候没有用DeepL ...
- centos7安装maven
下载maven 下载地址:http://mirrors.tuna.tsinghua.edu.cn/apache/maven/maven-3/3.3.9/binaries/apache-maven-3. ...
- 我们为什么需要Map-Reduce?
在讨论我们是否真的需要Map-Reduce这一分布式计算技术之前,我们先面对一个问题,这可以为我们讨论这个问题提供一个直观的背景. 问题 我们先从最直接和直观的方式出发,来尝试解决这个问题: 先伪一下 ...