Oleg Lebedev olebedev

Studying for a Tech Interview Sucks, so Here's a Cheat Sheet to Help

This list is meant to be a both a quick guide and reference for further research into these topics. It's basically a summary of that comp sci course you never took or forgot about, so there's no way it can cover everything in depth. It also will be available as a gist on Github for everyone to edit and add to.

Data Structure Basics

###Array ####Definition:

Stores data elements based on an sequential, most commonly 0 based, index.
Based on tuples from set theory.

First, check your current config (example output in homebrew.mxcl.postgresql.plist.xml lower down in this gist):

cat ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

Most importantly, note the -D /usr/local/var/postgres argument.

Second, shut down your current PostgreSQL.

launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

Go, multiple packages and coveralls.io

Single profile for single Go package

For Go projects that consist of only one package, the following Travis configuration is enough to get started with coveralls.io. You may want to encrypt your $COVERALLS_TOKEN via Travis encryption keys though.

language: go
go:
 - 1.3.1

	{ config, lib, pkgs, ... }:

	let

	libCrypto = with pkgs; stdenv.mkDerivation rec {
	name = "${pname}-${version}";
	pname = "minecraft-bedrock-server-libcrypto";
	version = "1.16-201.02";
	src = fetchurl {
	url = "https://minecraft.azureedge.net/bin-linux/bedrock-server-1.16.201.02.zip";

	# Parse a yarn.lock file using pure Nix
	# yarn.lock v1 files are basically YAML with support for having multiple keys for a single value in a map and without array support.
	# Inspired by https://github.com/yarnpkg/yarn/blob/158d96dce95313d9a00218302631cd263877d164/src/lockfile/parse.js

	with builtins;
	let
	# Add index to a list of elements
	enumerate = list: genList (i: ({ inherit i; e = elemAt list i; })) (length list);
	mkToken = type: value: { inherit type value; };
	parseLockfile = str: let

Service	Type	Storage	Limitations
Amazon DynamoDB	⚠️ Proprietary NoSQL	25 GB	⚠️ Payment method required
Amazon RDS	⚠️ Proprietary RDBMS		⚠️ Only free for 1 year
Azure SQL Database	MS SQL Server		⚠️ Only free for 1 year
👉 Clever Cloud	PostgreSQL, MySQL, MongoDB, Redis	256 MB (PostgreSQL)	Max 5 connections (PostgreSQL)

	{ fetchurl, fetchgit }:
	self:
	super:
	let
	registries = {
	yarn = n:
	v:
	"https://registry.yarnpkg.com/${n}/-/${n}-${v}.tgz";
	npm = n:
	v:

	#!/usr/bin/env bash

	# fresh-chrome
	#
	# Use this script on OS X to launch a new instance of Google Chrome
	# with its own empty cache, cookies, and user configuration.
	#
	# The first time you run this script, it will launch a new Google
	# Chrome instance with a permanent user-data directory, which you can
	# customize below. Perform any initial setup you want to keep on every