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GROKKING NOTES

I liked the way Grokking the coding interview organized problems into learnable patterns. However, the course is expensive and the majority of the time the problems are copy-pasted from leetcode. As the explanations on leetcode are usually just as good, the course really boils down to being a glorified curated list of leetcode problems.

So below I made a list of leetcode problems that are as close to grokking problems as possible.

Pattern: Sliding Window

1. Copy m3u8 link

2. Run command

echo "Enter m3u8 link:";read link;echo "Enter output filename:";read filename;ffmpeg -i "$link" -bsf:a aac_adtstoasc -vcodec copy -c copy -crf 50 $filename.mp4

Setup for MC Waterfall Server

sudo apt update && sudo apt upgrade

mkdir /home/server/games/minecraft/ && mkdir /home/server/games/minecraft/waterfall/ & mkdir /home/server/games/minecraft/project-1/ & mkdir /home/server/games/minecraft/project-2/ & mkdir /home/server/games/minecraft/project-3/ & mkdir /home/server/games/minecraft/lobby/ & mkdir /home/server/games/minecraft/survival/ & mkdir /home/server/games/minecraft/test-world/

scph5500.bin 26-Aug-2018 20:47 512.0K

scph5501.bin 26-Aug-2018 20:47 512.0K

scph5502.bin 26-Aug-2018 20:47 512.0K

Install docker

in case you haven't docker installed, please follow this instruction https://docs.docker.com/engine/install/ubuntu/

Expose docker port

First way

Create daemon.json file in /etc/docker, with content:

{"hosts": ["tcp://0.0.0.0:2375", "unix:///var/run/docker.sock"]}

	Create a file named user userconf (or userconf.txt) containing the following:
	pi:$6$c70VpvPsVNCG0YR5$l5vWWLsLko9Kj65gcQ8qvMkuOoRkEagI90qi3F/Y7rm8eNYZHW8CY6BOIKwMH7a3YYzZYL90zf304cAHLFaZE0
	Place userconf (or userconf.txt) plus an empty file named ssh (or ssh.txt) in the BOOT (FAT32) partition of the SD card.
	Insert the SD card in the Raspberry Pi and it should boot with access to user 'pi' (password : raspberry) via SSH.

	# -- coding: UTF-8 --
	# All credits go to: https://github.com/joren485/PyWinPrivEsc/blob/master/RunAsSystem.py
	from ctypes.wintypes import *
	from ctypes import *
	from enum import IntEnum

	# These libraries have the APIs we need
	kernel32 = WinDLL('kernel32', use_last_error=True)
	advapi32 = WinDLL('advapi32', use_last_error=True)
	psapi = WinDLL('psapi.dll', use_last_error=True)

	## Pre-requisite: You have to know your last commit message from your deleted branch.
	git reflog
	# Search for message in the list
	# a901eda HEAD@{18}: commit: <last commit message>

	# Now you have two options, either checkout revision or HEAD
	git checkout a901eda
	# Or
	git checkout HEAD@{18}

	create unlogged table int4_aa (id int, id2 int, col1 int, col2 int, col3 text, col4 text, col5 timestamptz, col6 timestamptz);
	create unlogged table int4_bb (id int, id2 int, col1 int, col2 int, col3 text, col4 text, col5 timestamptz, col6 timestamptz);

	insert into int4_aa
	select i, i, i, i, i, i, now(), now()
	from generate_series(1, 5*1e6) i;

	insert into int4_bb
	select * from int4_aa;

	/**
	script for exporting roll20 maps to an image

	how to use:
	1. open your roll20 game to the page you want to save
	2. open your browser's developer tools
	3. copy-paste this entire file in the console
	4. hit enter
	5. wait for map to save and appear in top-left
	6. right-click -> save as... to export