? 1. Concept introduction Tree DP is dynamic programming based on trees as a model. Mainly use the substructure brought by the tree itself (the parent-child relationship on the tree) to perform state transfer. Generally, the DP value of the parent node is derived from the DP value of the child node. 2. Detailed explanation […]
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[Data processing] python Matplotlib partially enlarges the figure; marks the local enlarged subfigure of interest
Foreword In data visualization, it is often necessary to partially enlarge the data in a certain interval to obtain a higher contrast visualization effect. The following uses the Matplotlib library of the Python language to implement a simple partial magnification effect. Dependent libraries matplotlib: plotting library numpy: an extended library that supports a large number […]
React technical principles and code development practice: from React Bootstrap to Semantic UI
1. Background Introduction React is one of the hottest front-end JavaScript frameworks currently. Its main advantages are simplicity, flexibility and performance. This article will combine my own research experience and work summary to share how to better understand and master some features and technical details of React. React has become a mainstream front-end UI framework, […]
Typical configuration of DNS server in Linux
Table of Contents BIND installation and deployment Forward analysis Programming zone configuration file Programming data configuration file Change the DNS address parameters in the network card to the local IP address (127.0.0.1) Reverse analysis Programming zone configuration file Programming data configuration file Check the results. Change the DNS address parameter in the network card to […]
React technical principles and code development practice: from components to life cycle
1. Background Introduction React is a JavaScript library for building user interfaces. It originated from Facebook, which implemented a front-end view layer framework in JavaScript and open sourced the project. Facebook is now at the helm full-time. React has many features, such as: Declarative programming: React adopts a declarative programming method, that is, using JSX […]
Call opencv library programming to display pictures and student ID names under Ubuntu
Article directory 1. Principle of Chinese character dot matrix font library (1), Chinese character encoding 1. Location code 2. Internal code (2) Dot matrix font structure 1. Bitmap font storage 2. 16*16 dot matrix font library 3. 1414 and 1212 dot matrix fonts (3). Acquisition of Chinese character lattice 1. Use location code to obtain […]
Call opencv library programming under Ubuntu to display a picture and display characters
? 1. Internal code, location code encoding rules and glyph data storage format of Chinese characters The in-machine code, location code encoding rules and glyph data storage format of Chinese characters are concepts related to Chinese character information processing. Here is a brief description: 1. Internal code: Internal code is the binary encoding used internally […]
React technical principles and code development practice: from PWA to Web Components
1. Background Introduction React is a JavaScript library for building user interfaces. It was originally open sourced by Facebook in 2013. Its powerful functions, excellent performance, simplicity and ease of use make it one of the most popular front-end frameworks currently. In recent years, the React community has also undergone some changes, including the rise […]
React technical principles and code development practice: React form processing and verification
1. Background Introduction Currently, front-end technology is changing with each passing day, and new technologies are emerging one after another. React, as the most popular Javascript library at the moment, is increasingly favored by developers. React is known as “the Facebook of JavaScript”. Its advantages include componentization, declarative programming, JSX syntax, etc., and React Hooks […]
Using JsSIP for audio and video calls in Vue
JsSIP official website address: https://jssip.net/download/ Download the JsSIP plug-in: npm install jssip; Introduced into the project: import JsSIP from “jssip”; Initialize SIP let currentSession; let userAgent; let peer; var msg_log = null; sip_init () {<!– –> let _this = this; msg_log = {<!– –> el: document.querySelector(“.message”), log(msg) {<!– –> console.log(“msg”, msg); this.titleText = msg; this.el.innerHTML […]