Personal revision notes — includes exact commands run, concepts explained, and the reasoning/misconceptions along the way (so future-me doesn't repeat the same wrong turns).
.bat scripts under bin\windows\, not the .sh scripts)
NOTE: If docker is not installed in your machine first do that before following next.
Official Docker Image: https://hub.docker.com/_/postgres
docker run -d \
--name postgres-db \
-p 5432:5432 \
-e POSTGRES_USER=myuser \
This is a sorting algorithm that sorts the array in stable, non-comparision way. We never compare anything in this.
This is based on the the Count Sort. Learn about this it's very very simple.
Count sort usually works best when we have small range of number that we want to sort. Why only small range??
Because in the algorithm we find the maximum number from array and create the array of size MaxNumber + 1 which is used to keep the
count/freq of each element that is present in the array.
Go and learn yourself.
Wrote notes by self reformatted by chatgpt
A computer contains a CPU (Central Processing Unit), which has one or more physical cores. These are the actual hardware cores present on the processor.
For example:
Docker is a tool that help us to work with the containers. We can pull the images from it's public docker hub repo and run the images in our machine to work with softwares like nodejs, mongodb, linux which otherwise needs to be installed on our Operating System manually.
Containers are the isolated environments in your system that runs on the top of your systems infrastructure but are in isolation. Containers itself doesn't contain the full operating system but rather it contains some binaries. Docker sits in between our machine Operating system and the Container to manage how we use the our computer resources.
to share the container we create the Images of our container which can be replicted on other machine.
Images can also be created from Dockerfile.
Redis does not natively support Windows, the recommended and easiest way to run it is by using Windows Subsystem for Linux (WSL) or Docker. Alternatively, you can use Memurai, which is an officially supported native port for Windows.
wsl --installbashsudo apt-get update
This code comes from this youtube channel The Complete Guide to WebSockets one of the best channel to learn Networking and Deep dive concepts of System Design etc.
const http = require("http");
const WebSocket = require("websocket").server;
let connection = null;
We use Dijkstra algorithm to find the minimum distance from single srouce(src) to all other vertex in the given graph. It works only on Undirected Weighted Graph which are not having negative edge weights. It uses a greedy approach that repeatedly minimize the distances to other vertices.
We use priority queue to implement Dijkstra's algorithm.
The theory part you can learn on the Internet.