Carlos Silva crashtech

Math Code Challange

Written for BSIT 330: Discrete Mathematics (Westcliff University), on April 25, 2021
Reviwed on September 22, 2024

As a common practice, developers are requested to complete code challenges to assess their knowledge of a specific language or prove a certain level of experience in logical conundrums. Usually, such tests ask the programmer to receive a specific input and provide an output based on a series of criteria. Sometimes, the expected solution has to be elegant, be aware of edge cases, and work relatively fast given heavier inputs. However, there are cases that the best solution could be found using a comprehensive understanding of mathematics or other subjects. That is undoubtedly the case of the challenge that is going to be presented in this paper.

Ruby on Rails, from MVC to GraphQL

As a Ruby on Rails developer, I'm always looking for the best tools and practices to apply to my day-to-day development. This framework has a fantastic structure where all its inner parts communicate very well. But, as applications start growing, or developers want to start using more modern technologies, several things start getting out of control.

Recent versions of Rails implemented Webpack, facilitating the use of modern JavaScript frameworks, which added another level of robustness to everyone's applications. Not only is this becoming the new standard, but it also enables bigger code-bases without falling into madness.

Facebook, as the creator of ReactJS (one of these modern JS frameworks and the most popular one) introduced to the world another of its technologies, GraphQL. This tool, like any other tool, can be a great asset, as long as it's in the right hands, meaning that you first need to know what role it plays before exploring how to use it in your RoR appli

	# This is the PEG-based grammar for GraphQL based on:
	# https://spec.graphql.org/October2021/#sec-Document-Syntax
	#
	# It is also inspired by another PEG grammar of GraphQL for JavaScript:
	# https://github.com/madjam002/graphqlite/blob/master/grammar.pegjs
	#
	# This only complies with the GraphQL spec with no further additions, focusing
	# only the Executable Definitions, to optimize the output and processing

	grammar Rails.GraphQL.Parser

	Small Crunchy Finger Basket
	{"ref":"MenuItem:06129e99-923f-4e0d-8863-f4f295b5f419","id_field":"guid","pos_active":true,"title":"Small Crunchy Finger Basket","price":9.55,"image_url":"https://s3.amazonaws.com/toasttab/restaurants/restaurant-26036000000000000/menu/items/3/item-400000004246731573_1582403485.jpg","description":"3 fingers with 1 sauce and french fries.","tax_rate":15.5,"observation_flags":{"suspend_until_flags":{"sold_out_in_pos":"observed"},"alcohol_problems":{"observed_missing_alcohol_state_from_pos":"observed"}}}

	Classic Fries
	{"ref":"MenuItem:a9537c02-dc72-45a2-bddd-a8da9af5263d","id_field":"guid","pos_active":true,"title":"Classic Fries","price":4.45,"image_url":"https://s3.amazonaws.com/toasttab/restaurants/restaurant-26036000000000000/menu/items/2/item-400000004249845722_1582410894.jpg","description":"3/8th\" straight cut fries with crispy batter.","tax_rate":15.5,"observation_flags":{"suspend_until_flags":{"sold_out_in_pos":"observed"},"alcohol_problems":{"observed_missing_alcohol_state_f

	CHECKERS = {
	'cats' => :>,
	'trees' => :>,
	'pomeranians' => :<,
	'goldfish' => :<,
	}

	def find_aunt(criteria, input)
	input.scan(/Sue (\d+): (.*)\n/).find do \|(number, data)\|
	break number if data.scan(/(\w+): (\d+)/).all? do \|(item, value)\|

	# app/models/topic.rb
	class Topic < ApplicationRecord
	self.table_name = 'topic'

	## Associations
	has_many :posts

	## Validations
	validates :name, presence: true
	end

	SELECT "stories"."id" AS "Id",
	"stories"."title" AS "Title",
	"stories"."publication_id" AS "Publication Id",
	"publications"."name" AS "Publication Name",
	"story_authors"."authors" AS "Authors",
	"stories"."date" AS "Date",
	"stories"."media_type" AS "Media Type",
	"stories"."url" AS "URL",
	"stories"."length" AS "Length",
	"stories"."solutions_3" AS "Solutions 3",

	def cosine_distance(this, that)
	return 1.0 if this === that

	a_vector = Hash.new(0).tap{ \|v\| this.each{ \|e\| v[e] += 1 } }
	b_vector = Hash.new(0).tap{ \|v\| that.each{ \|e\| v[e] += 1 } }

	a_mag = 0.0
	product = a_vector.inject(0.0) do \|total, (key, value)\|
	a_mag += value ** 2
	total += value * b_vector[key]

	SELECT "orders"."id" AS t0_r0,
	"orders"."customer_id" AS t0_r1,
	"orders"."vendor_id" AS t0_r2,
	"orders"."billing_address_id" AS t0_r3,
	"orders"."shipping_address_id" AS t0_r4,
	"orders"."status" AS t0_r5,
	"orders"."partner_order_number" AS t0_r6,
	"orders"."created_at" AS t0_r7,
	"orders"."updated_at" AS t0_r8,
	"orders"."description" AS t0_r9,

	+ 1491966648.266378976 /scripts/cli : __rvm_parse_args() 749 > [[ -z '' ]]
	+ 1491966648.271087905 /scripts/cli : __rvm_parse_args() 749 > [[ -n '' ]]
	+ 1491966648.275022367 /scripts/cli : __rvm_parse_args() 752 > [[ error == '' ]]
	+ 1491966648.278861310 /scripts/cli : __rvm_parse_args() 752 > [[ 0 -eq 1 ]]
	+ 1491966648.282690210 /scripts/cli : __rvm_parse_args() 752 > [[ -n '' ]]
	+ 1491966648.286148429 /scripts/cli : __rvm_parse_args() 15 > [[ -n use ]]
	+ 1491966648.289327313 /scripts/cli : __rvm_parse_args() 17 > rvm_token=use
	+ 1491966648.292945688 /scripts/cli : __rvm_parse_args() 19 > (( 1 > 0 ))
	+ 1491966648.296664270 /scripts/cli : __rvm_parse_args() 21 > next_token=/home/poc.myadmin.dev/
	+ 1491966648.300582448 /scripts/cli : __rvm_parse_args() 22 > shift