Life is like a Markov chain, your future only depends on what you are doing now, and independent of your past.

Tiger Memo

“Install Free SSL Certification On Your Website”

Install Free SSL Certification On Your Website Introduction Let’s Encrypt is a free, automated, and open certificate authority (CA), run for the public’s benefit. It is a service provided by the Internet Security Research Group (ISRG). Environment Server: Centos 7.0 Prerequisites An availabe website deployed on a server A domain name can be resolved by DNS Server Web Server like Nginx, Apache , etc. Choose Your System and Web Server Let’s Encrypt suppiles automatically deployment by using Certbot.

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“Data Structures and Algorithm Analysis Note (I)”

Basic Knowledge before learning Algorithm & Data Structures Four basic rules of recursion Base cases Making progress Design rules: Assume that all recursive calls work. Compound Interest Rule: Never duplicate work by solving the same instance of a problem in separate recursive calls. Two most common ways of proving statements: by induction and by contradiction. Modular Arithmetic: A is congruent to B modulo N, written A ≡ B if N divides A – B (The remainder is the same when either A or B is divide by N.

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“Data Structures and Algorithm Analysis Note (II)”

ADT An ADT is a set of operations; ADTs are mathematical abstractions; nowhere in an ADT’s definition is there any mention of how the set of operations is implemented. Operations for the set ADT: Union Intersection Size Complement The List ADT Empty list—the special list of size 0. Operations: Find: returns the position of the 1st occurrence of a key;

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“Hackers & Painters 读书笔记 （中文）”

Hackers & Painters: Big Ideas from the Computer Age is a collection of essays from Paul Graham discussing hacking, programming languages, start-up companies, and many other technological issues. “Hackers & Painters” is also the title of one of those essays. Paul Graham: He is an English born computer scientist, entrepreneur, venture capitalist, author, and essayist. He is best known for his work on Lisp, his former startup Viaweb (later renamed “Yahoo!

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“Installing Nginx on CentOS and its Basic Configuration”

Installing Nginx on CentOS and its Basic Configuration Environment Server: Centos 7.0 Installation sudo -y install nginx Before Configuration Make sure you have backed up the nginx.conf file. Configuration vi /etc/nginx/nginx.conf Basically, you can change the port nginx listend and the root of your site. Result If you have finished steps mentioned above, you may access a welcome page or your index page by your IP address or domain name.

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“SSH Configuration on GCP”

SSH Configuration on GCP Environment Server: Centos 7.0 Workstation: macOS Mojave 10.14.2 Generate a Key Open a terminal, using ssh-keygen tool. ssh-keygen -t rsa -f ~/.ssh/[KEY_FILENAME] -C [USERNAME] The USERNAME should be identical to the counterpart of your instance. You must restrict access to your private key or you will get a denial when you try to connect the server using ssh command chmod 400 ~/.ssh/[KEY_FILENAME] The key generated was stored at ~/.

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