• 01 Package 背包 Dynamic Programming

    I've been studied 01 Package for so many times. But I keep forgetting it. It costs me so many energy every time I learn, especially for the optimization of space complexity. So I take notes this time.



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  • Database Project: SQL Grammar Analysis Ⅰ

    This is a very simple version of SQL grammar. For the sake of time, I just write some very basic usage.



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  • Database Project: SQL Lexical Analyzer词法分析

    数据库项目目前实现了一个简单的词法分析器，其中就是读取SQL语句中的字符，把他们转换成相应的Token。



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  • HEXO主题开发——构建主题框架

    主题重构Day1-2，详细地写一些搭建环境和框架遇到的bug，以己如何解决方法。详细记录了一些开发时的心理状态作为日后的乐趣。



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  • Install Basemap of Python(Linux)

    Basemap is a plug-in of matplotlib. Matplotlib is a drawing library that helps to draw data in multiple ways using python. And Basemap is used to draw maps. The followings are steps to install basemap.



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  • Numerical Characteristics of Rando variables

    第四章 随机变量的数字特征

    一、数学期望

    1. 离散型
      $$
      E(X)=\sum_{k=1}^{\infty} x_{k} p_{k}
      $$

      当上式发散时，$X$的数学期望不存在。



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  • PicGo+GitHub+Typora for Blog

    Recently, while trying to accelerate my blog load speed, I also want to get all my pictures a cdn. Also I’m tired of uploading the picture every time I want to quote a picture in my post, So I found a softeware PicGo.



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  • 计算机中的数据表示

    最近开课计算机组成原理，由于疫情原因，老师推荐的华中科技大学的秦磊华老师讲的MOOC上的课程。感觉学习难度比较大，因为基础薄弱，所以来总结一下学习的知识，加以巩固。



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Linear Algebra
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vectors and spaces

  1. intro:

    $\left[\begin{array}{lll}x & x & x\end{array}\right] \rightarrow$ element amount $(n)=n$ dimension

    $\mathbb{R}^n$ (e.g. n = 3 3 Dimension)

    vectors and spaces
Machine Learning
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Model representation

To describe supervised learning,we establish notation for future use.

**$x^i$ **denote the input variables also called input features

**$y^i$ ** denote the output variables also called target variables that we are trying to predict.

A pair **($x^i, y^i$) **is called a training set.

Knowledge points
C++
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Check for alphabet characters

                                                                                      

usage
ACM
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P1533 Number Reverse

we just find the position of the character '.' and '/' and '%' and reverse the string before and after the character and omit the front zeros.

String洛谷
C++
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Usage of string.find()

Every time I use find function in C++ , I always search its usage after using it for so many times. So I decide to make a summary of some commonly used usages.

usage
Algorithm
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KMP

KMP is an algorithm that find the given pattern string in the pending string. Usually we would think of violent traversing the two strings using for loop. However the time complexity of this method is O(n)~O(mn). So the KMP can cut the times of loop.

Knowledge pointsStringKMP
Blog
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Add Comments

Because of my first theme was so incomplete that I need to add many features myself. So I’ve looked for how to add comment system on the blog.

comment
Blog
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Change Blog Theme

Last time I‘ve talked about how to build your own blog, however, the original theme might not very beautiful to you. So this time I would write how to change your blog theme and others.

theme
Algorithm
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Inclusion Exclusion Principle

In combinatorics (combinatorial mathematics), the inclusion–exclusion principle is a counting technique which generalizes the familiar method of obtaining the number of elements in the union of two finite sets; – From Wikipedia

Knowledge pointsMathInclusion Exclusion Principle
ACM
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Prime factor of n

                                                                                      

Knowledge pointsMath
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