Victor Ray victorray84

Cache Oblivious and Cache Aware Data Structure and Algorithms

Cache-Oblivious Algorithms and Data Structures - Erik Demaine (One of the earliest papers in cache oblivious data structures and algorithms that introduces the cache oblivious model in detail and examines static and dynamic cache oblivious data structures built between 2000-2003)
Cache Oblivious B-Trees - Bender, Demaine, Farch-Colton (This paper presents two dynamic search trees attaining near-optimal performance on any hierarchical memory. One of the fundamental papers in the field where both search trees discussed match the optimal search bound of Θ(1+log (B+1)N) memory transfers)
Cache Oblivious Search Trees via Binary Trees of Small Height - Brodal, Fagerberg, Jacob (The data structure discussed in this paper works on the version of [2] but avoids the use o

Basics

B-trees and CPU Caches

Deploying nodejs on AWS

1. Create AWS EC2 instance

We would prefer to go with Ubuntu Server 16.04 LTS (HVM) [ami-0d03add87774b12c5] for backward compatibility for older applications. But one can choose any version as per thier preference

2. Install nvm and Nodejs using nvm

Group Array of JavaScript Objects by Key or Property Value

Implementation

const groupBy = key => array =>
  array.reduce((objectsByKeyValue, obj) => {
    const value = obj[key];
    objectsByKeyValue[value] = (objectsByKeyValue[value] || []).concat(obj);
    return objectsByKeyValue;

Noteful Challenge - One-to-Many

In this challenge you will create a folders table, create a new router and endpoints for the folders, and update the existing notes endpoints to return folder related data.

Requirements

Create a folders table
- Optionally, alter the default sequence so the folder IDs start at 100
Add a folder_id column to the notes table and define the relationship
Populate the folders table with sample data and update the notes data to include folders.

First

Create function

create or replace function bytea_import(p_path text, p_result out bytea) 
                   language plpgsql as $$
declare
  l_oid oid;
  r record;
begin
 p_result := '';

Knex Setup Guide

Create your project directory

Create and initialize your a directory for your Express application.

$ mkdir node-knex-demo
$ cd node-knex-demo
$ npm init

	import * as Sentry from "@sentry/node";
	import imagemin from "imagemin";
	import mozjpeg from "imagemin-mozjpeg";
	import sharp from "sharp";
	import isJpg from "is-jpg";
	import * as aws from "aws-sdk";
	import { Upload } from "../../types/graphqlUtils";
	import { generateFilename } from "./generateFilename";

	export const s3 = new aws.S3({

	// Douglas Hill, December 2018
	// Made for https://douglashill.co/reading-app/
	// Find the latest version of this file at https://github.com/douglashill/KeyboardKit

	import UIKit

	/// A table view that allows navigation and selection using a hardware keyboard.
	/// Only supports a single section.
	class KeyboardTableView: UITableView {
	// These properties may be set or overridden to provide discoverability titles for key commands.

	//
	// UIView+Constraints.swift
	// CiLabs
	//
	// Copyright © 2019 Netguru.co. All rights reserved.
	//

	import UIKit

	typealias Constraint = (_ layoutView: UIView) -> NSLayoutConstraint