【★】Welcome Post

Post updated on 2020/1/18

Welcome to XGN’s Personal Blog /欢迎

As a sequal to the XGN’s previous (dead) blog and HHS’s blog, this page will be my new own personal space! Hooray!!

欢迎欢迎！！

Only articles with “English” tagged will be available in English

只有标记了”Chinese”标签的文章才会有中文。

What to post /发什么

Mainly something more personal, like game/music reviews, status, ~~furry~~ and personal OC. I will also temporarily put ZKY’s articles here. Please also stay tuned for HHS Blog as I will post stuffs there too!

主要是一些更私人化的东西，比如游戏/音乐评论，状态，~~furry~~和个人OC。我还会暂时将ZKY的文章放在这里。请继续关注HHS博客，因为我也会在那里发布文章！

You may see the blog isn’t maintained often and I don’t really post blogs on HHS Blog often either. You can assume I will only put stuffs here now. Still, whenever there’s something I post on HHS Blog that is really important and personal, I will post it here or make a hyperlink too!

你可能会看到博客不经常维护，我也不经常在HHS博客上发布博客。你可以假设我现在只在这里放东西。尽管如此，每当我在HHS博客上发布一些非常重要和私人的东西时，我都会在这里发布或者做一个超链接！

How to post /怎么发

This page is powered by Github Page. It’s built using Hexo and Github Workflow to auto deploy.

此页面由Github页面提供支持。它是使用Hexo和Github工作流来自动部署的。

Link / 友情链接

HHS Blog

Game Review

一种基于维护高度的无递归、无栈、无parent指针的AVL树实现方式

引入

AVL树有种种实现方式，其中最自然的是采用递归的写法，毕竟AVL树是递归定义的。但是，有的老师认为“递归时间常数大”，觉得应该用迭代。但是，还有老师认为迭代要用栈，“栈空间大（指占用了）空间”，不能用栈。自然，我们可以用parent指针规避掉这一问题，但是显然parent指针需要使用的额外内存更大，这位老师还是不喜欢。所以现在我们被要求实现三无AVL——无递归、无栈、无parent指针。

AVL树的维护方法有两种：维护高度和balance factor（BF）。笔者认为Balance Factor不够优雅、泛用性低、过于特殊化，故采用维护高度的方式。

所以，本文认为，三无AVL实现的重点在于 快速的维护每个节点子树的高度。

2024-09-13

Dev►Java

Building a Clear Programming Language for Newcomers

This is a joke

Introduction

Many new programmers are often confused about a very important concept in programming: the variable lifespan. For example, one could not understand why the variable “a” is “not defined” when it’s clearly there:

int x=3;
{
	int a=4;
}

a; //Compile Error

Another problem newcomers face when they are first presented callback functions are that they are not able to convert sequential code into callback functions. When the program gets complicated, it is common for a professional programmer to combine the callback functions and sequential coding. When this happens, newcomers may not know the correct order of execution, leading to frustration.

One more problem comes from the “impossible” mission for coding: naming things. Professional coder might use what are called “defensive programming” by naming variables weirdly, like just calling them q fa wps sht etc.

In order to make programming more accessible to beginners, we have developed the latest programming language: CLang!

2024-09-06

Dev►Web

Displaying Attachment PDF with Frontend Javascript

背景

笔者最近在参加某校在线平台前端的开发，收到了这样的要求：

将服务器传输过来的文件尽可能（图片/PDF）在网页中就显示下来，这样就不用下载了！

笔者劈里啪啦敲下了如下代码（由于渲染问题，美元符号已替换为人民币符号！！！）：

var xhr = new XMLHttpRequest();

￥.ajax({
	url: 'download_link',
	type: 'get',
	data: {},
	xhr: function () {
		return xhr;
	},
	success: function (r) {
		const params = new URLSearchParams(xhr.responseURL);
		const para1 = params.get('filename');
		console.log("Returned url:"+xhr.responseURL);
		console.log(para1);

		if (para1 == null) {
			￥('#fast_load').text('');
			return;
		}

		if (para1.endsWith(".png") || para1.endsWith(".jpg") || para1.endsWith(".gif") || para1.endsWith(".bmp")) {
			￥('#fast_load').html(`用户上传的图片（为正常显示，已缩放。请点击下载按钮下载原图。）<br/><br/><img src="￥{xhr.responseURL}" style="max-width:600px;width:100%"/>`);
			return;
		}

		if(para1.endsWith(".pdf")){
			￥('#fast_load').html(`用户上传的PDF<br/><br/><object class="pdf" data="￥{xhr.responseURL}" width="100%" height="1500"></object>`);
			return;
		}
		
		￥('#fast_load').text(`用户上传了文件：￥{para1}，请按下载按钮下载。请注意：本网站不对用户上传内容进行检查，文件有可能包含恶意内容。`);
	}
});