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This is the 277th update of Yueyue Book, 293 original works. 01 Look at the topic and prepare Today, we introduce LeetCode algorithm question 145 at the Easy level (rank 637). Given a non-empty binary tree, the average value of the sum of node values at each level is returned as an array. For example: 3 / \ 9 20 / \ ...

The preparatory documents are as follows: 1.CentOS-6.4-x86_64-bin-DVD1.iso 2.jdk-7u67-linux-x64.rpm 3.apache-tomcat-7.0.55.tar.gz The installation steps are as follows: Installation of JDK [root@n1 /]# java -version bash: java: command not found [root@n1 /]# rpm -ivh /soft/jdk-7u67-linux-x64.rpm Preparing... ############# ...

1. Installing JDK Running Environment #cd /opt  #wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u112-b15/jdk-8u112-linux-x64.tar.gz  #tar zxvf jdk-8u112-linux-x64.tar.gz  #Vi/etc/pro ...

1. Log on to a remote Linux server: [c:\~]$ sftp root@192.168.233.136 1.1. Enter for certification: 1.2. The login was successful: Upload files to server: 2.1 Upload Operation Drag and drop the file to the current window. Another way - using commands: sftp:/root> lcd E:\Installation package\linux l ...

Yesterday, I ran yum update on the system. There were many updates. So I clicked Y as before, and the system was updated slowly. After the updates were restarted, it was tragic that the desktop could not come out. I could not download the latest NVIDIA driver installation and report all kinds of errors. So I went to the ...

[Re-learning Java Foundation] [JavaIO Stream] [Part.6-2] Stream Decoder and Stream Encoder StreamDecoder Summary This class is under the sun.nio package In the previous Oracle official JDK, you can only download OpenJDK to see the source code. Or check it online at grepcode openJDK Online Source But since Java 9, O ...

The last line needs to be retained. There are two JDK versions: json-lib-2.1-jdk13.jar and json-lib-2.1-jdk15.jar. <dependency> <groupId>net.sf.json-lib</groupId> <artifactId>json-lib</artifactId> <version>2.4</version> <classif ...

Requirement: I have a collection, as follows, I want to determine whether there is a "world" element in it, if there is, I add a "javaee" element, please write code implementation. The code is as follows: public class Test {           public static void main(String[] args) {               List&l ...

One sentence to explain what package management tools are It's Android's app store. Each major distribution of linux comes with its own package management tools. Now take installing jdk as an example to illustrate their command-line usage. ubuntu 14.04 (dibian system) root@552b680ba26a:/# apt update ...

This article mainly shows you how to use JavaExcel API to read and write Excel files. With regard to the JavaExcel API, this is an open source lib library. The related feature s are as follows: Supports Excel 95, 97, 2000, XP, 2003 tabulation pages.Can read and write related Excel formulas (only support Excel 97 and later versions)Excel 2000 fo ...