• Leetcode practice – bit operation (division of two numbers, numbers that appear only once, repeated DNA sequences, etc.)


    preface The operation of 0 and 1 is the bottom operation of the computer. All programs, no matter what language they are written in, must be transformed into a language that the machine can understand, that is, binary for basic operations, and these basic operations are the bit operations we want to talk about today. […]

  • “Yunguang” international exhibition, CES 2021 wonderful products selection!


    CES is a large-scale consumer electronics exhibition held in Las Vegas in January every year. This year, due to the special reasons of the epidemic, this large-scale exhibition, which has been held for more than 50 years, has been switched to online for the first time. According to the American consumer Technology Association, about 4000 […]

  • Initial websocket


    I’ve always been interested in real-time communication. I took the time to learn about websocket this week. websocket Websocket is a network transmission protocol, which can carry out full duplex communication on a single TCP connection. It is located in the application layer of OSI model. Websocket makes the data exchange between the client and […]

  • Websocket from entry to mastery, half an hour is enough!


    The original title of this article is “websocket: 5 minutes from getting started to mastering”, and the author is “program ape small card”_ Casper “, see the resources section at the end of the text for a link to the original text. There are changes in this collection. 1. Introduction Since the emergence of websocket […]

  • JS file transfer, 10 HTML file upload skills, web user experience design improvement guide, strange knowledge — bitmask | si no technology weekly


    Today, I share the knowledge points to improve work happiness. I hope you don’t miss these good articles~ 1、JS files Base64, file, blob and arraybuffer are transferred to each other Binary conversion File object to Base64 let reader = new FileReader();  reader.readAsDataURL(file[0])  console.log(reader) Convert Base64 to blob upload function dataURItoBlob(dataURI) {       var byteString = atob(dataURI.split(‘,’)[1]);       var mimeString = dataURI.split(‘,’)[0].split(‘:’)[1].split(‘;’)[0];       var ab = new ArrayBuffer(byteString.length);       var ia = new Uint8Array(ab);       for (var i = 0; i < byteString.length; i++) {           ia[i] = byteString.charCodeAt(i);       }       return new Blob([ab], {type: mimeString});   } Convert […]

  • Locking pages while waiting for long operation based on angular


    Due to the network and other reasons, sometimes it takes a long time to execute an Ajax operation. If you don’t do special processing, you can’t know the status of the current operation, which seriously affects the user experience. A common solution is to open a mask before performing a possible long operation, cover the […]

  • Qianxin school move: buy masks (c + +)


    ⭐ Article link: www.mengyingjie.com/archives/38/ ⭐ Time limit: 1 second for C / C + + and 2 seconds for other languagesSpace limit: C / C + + 26214k, other languages 524288K64bit IO Format: %lld Title Description Xiaoming has n yuan to go to the drugstore to buy masks. There are 6 brands of masks in […]

  • [Android systrace series] capture the startup process of systrace


    ————————————————————————- The small goal of this article is to understand the steps of grabbing systrace in the boot process ————————————————————————-   Mobile phone boot process, involving a lot of code, if you can use systrace to analyze, get twice the result with half the effort. First, decompose the time-consuming of each startup stage to facilitate […]

  • The error boundaries of react


    Error boundaries Starting from react V16, the concept of boundary error is introduced. Core API getDerivedStateFromError componentDidCatch 1. Purpose: some UI crash, not the whole webapp crash 2. Attention ⚠️: Error bounds cannot capture errors in the following scenarios Event handling (learn more) Asynchronous code (for examplesetTimeoutorrequestAnimationFrameCallback function) Server rendering Errors thrown by itself (not […]

  • On the HTML 5 page, click the mask layer background to close the mask layer


    Today, my team members received a demand. The demand is like this. Click the page button to pop up a red envelope pop-up window to display the black mask layer. Click the background of the mask layer and the pop-up window close button to close the pop-up window. So I made a demo to facilitate […]

  • Half an hour is enough for websocket to be proficient!


    The original title of this article is “websocket: 5 minutes from introduction to Mastery”_ See the resources section at the end of the article for a link to the original text. There are some changes in this collection. 1. Introduction Since the emergence of websocket in HTML5, it has completely changed the “pain point” of […]

  • Significantly optimize PNG image size with CSS mask (recommended)


    This article is welcome to share and aggregate, full text reprint is not necessary, respect copyright, the circle is so big, if urgent need can contact authorization. 1、 Png images that cannot be further compressed For example, there is a PNG image as shown below (size 1 / 2 is shown), and there is still […]