[17] Alphabet combination of island number and phone number

*Content from leetcode 1. Number of islands Subject requirements Given a 2D grid consisting of ‘1’ (land) and ‘0’ (water), please count the number of islands in the grid. Islands are always surrounded by water, and each island can only be formed by connecting horizontally and/or vertically adjacent land. Also, you can assume that the […]

No 2. JPA(Hibernate) + MySql 5.x integration

No 2. JPA(Hibernate) + MySql 5.x integration Note that the MySQL service must be installed in advance to continue, this section. 1. Create directory structure 2. Add JPA, MySql dependency (pom.xml) <!–mysql dependency–> <!–mysql dependency and JPA dependency sequence will lead to package import failure–> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.13</version> </dependency> <!– https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-jpa –> <dependency> <groupId>org.springframework.boot</groupId> […]

Empty folders cannot be deleted and cannot be opened, “The item does not exist, please confirm the location of the item”, “The item is being opened and cannot be deleted”, “The file is damaged or has been moved and deleted” (multiple methods with graphic explanations, details Need to pay attention, and possible problems)

1. Preliminary summary – the situation that triggers this folder This file or folder that cannot be deleted is actually an ancestral bug of the Windows system that has not been fixed so far, so we need to deal with it through special means. Listening to my slow talk about his reasons may be helpful […]

Python practical application explanation-[numpy special topic] numpy application case (1) (with python sample code)

Directory Analyzing the sale price of a used car with Python Pencil sketches for building GUI applications in Python package needed Implementation steps full code Using Python to analyze the sales price of used cars Today, with advancements in technology, techniques like machine learning are being applied at scale in many organizations. These models usually […]

Circle equal division coordinate calculation program (calculation optimization without floating point calculation)

Circle equal division coordinate calculation program mathematical principles programming Make a table of trigonometric functions Calculate coordinates demo program Principles of mathematics Assume that the circle N with a radius of R is equally divided. The index k starts at 12 o’clock and is arranged clockwise, then each coordinate point The general calculation formula is: […]

Linux thread | create terminate recycle detach

1. Thread introduction A thread is the smallest unit that participates in system scheduling. It is included in the process and is the actual running unit in the process. Multiple threads can be created in one process, multiple threads can run concurrently, and each thread can perform different tasks. Each thread has its corresponding identifier, […]

CoordConv: Add coordinates to your convolution

This article is from the AlStudio community boutique project, [click here] to view more boutique content >>> CoordConv: Add coordinates to your convolution 1. Theoretical introduction 1.1 Detailed explanation of CoordConv theory This is an archaeological paper reproduction project. When the Uber team proposed the CoordConv module in 2018, many articles criticized it, thinking that […]

[In-depth explanation of Yarn architecture and implementation] 5-2 Yarn three schedulers

This article will give an in-depth introduction to the three schedulers of Yarn. Yarn itself is a resource management and scheduling service, and the resource scheduling module is the most important. The following will introduce the scheduler function implemented in Yarn, as well as the internal execution logic. 1. Introduction The main function of Yarn […]

Mybatis-Plus implements pagination query

Mybatis-Plus implements paging query Article directory Mybatis-Plus implements pagination query 1.1 Technical overview 1.2 Technical details 1.2.1 Configure the pagination plugin 1.2.2 Custom pagination 1. If your mapper does not inherit from BaseMapper 2. If your mapper inherits BaseMapper 1.3 Problems and solutions encountered in the use of technology 1.4 Summary Mybatis-Plus implements paging query […]