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prefaceArrayList is a List implemented by array. Compared with array, it has the ability of dynamic expansion, so it can also be called dynamic array.Any type of data can be stored in the ArrayList collection, and it is a sequential container. The order of stored data is consistent with the order we put it in, and it also allows us to put null ...

[problem description] Given a complete binary tree with N nodes, each node in the tree has a weight, which is A1, A2, ···· AN from top to bottom and from left to right, as shown in the following figure: Now Xiao Ming wants to add up the weights of nodes with the same depth. He wants to know which depth has the ...

This article is reproduced from: https://zhuanlan.zhihu.com/p/36233589 Record learning only~ summary This chapter is just a summary of the routine operation of pytorch. It's good to have an impression in your mind. You know that there is such a thing. You can look at it in detail when you need it. In addition, you still need to use it in prac ...

catalogue 1, What does actionlib do? 2. How to implement this operation in non ros system? 3, Write front-end code and detailed comments in HTML 4, Some understanding of actionlib on the server side 1, What does actionlib do? Actionlib is a very important library for ROS. For example, when performing various movements, such as controllin ...

Understanding time complexity: Constant time operation: if an operation has nothing to do with the amount of data, it is completed within a fixed time every time, which is called constant operation. Time complexity is an indicator of the number of constant operations in an algorithm flow. It is often represented by 0 (pronounced big0). S ...

3.2 execution of capacity load test We use the bisection approximation method to find the inflection point of capacity load test, inject data into the database with python script, and delete the data with delete SQL statement. The number of fixed online users is 100, and each test still runs for 10 minutes. If the test error percentage is with ...

Article catalogue SQL Birth of SQL Standardization SQL:2019 SQL:2016 SQL:2011 SQL:2008 SQL:2006 SQL:2003 SQL:1999 SQL-92 Language characteristics Statement classification SQL realization NewSQL The birth of SQL It was a summer in ...

preface Recently, the teacher of computer class has gone through [database establishment and maintenance], [database table and index creation], [single table query] and [multi table query], but his mind is still messy, so he sorted out this note for future sorting and review. The main content is the query of single table and multi table. ...

kafka installation record: Official website: http://kafka.apache.org/downloads.html 1. Download yum install -y wget wget https://mirrors.bfsu.edu.cn/apache/kafka/2.6.0/kafka_2.12-2.6.0.tgz 2. Decompression: tar -zxvf kafka_2.12-2.6.0.tgz -C /opt/ 3. Change of name mv kafka_2.12-2.6.0 kafka 4. Create files cd kafka Create un ...

1. Preface Cut point and bridge, a branch of graph theory, are often implemented by Tarjan algorithm. Yes, it's this algorithm again Note that the implementation of Tarjan algorithm in cut point and bridge is different from that in strong connected component. Pre knowledge: dfs tree / dfs order 2. Cutting point Example: P3388 [formwo ...