sanchojaf

ensure that you have rails 4.2 like envioroment

git clone git://github.com/RailsApps/rails-stripe-membership-saas.git

cd rails-stripe-membership-saas

bundle

rake db:migrate

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json_payload = 
"{
  \"orders\": [
    {
      \"id\": \"R123456789\",
      \"status\": \"complete\",
      \"channel\": \"spree\",
      \"email\": \"spree@example.com\",
      \"currency\": \"USD\",
      \"placed_on\": \"2017-03-10T15: 20: 43Z\",

sanchojaf

# The traverse iterator will iterate over the tree in the same
# breadth-first order.

class Tree
  attr_accessor :left
  attr_accessor :right
  attr_accessor :data

  def initialize(x=nil)
    @left = @right = nil

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# We have a pole with a certain number of disks staked on it; 
# call this the source pole. We want move all of these to the
# destination pole, using a third (auxiliary) pole as an
# intermediate resting place. The catch is that you can move
# only one disk at the time, and you cannot ever place a larger
# disk onto a smaller one.

def towers(list)
  while !list.empty?
    n, src, dst, aux = list.pop

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Matching Keyword-Value Pair (regular expressions, ruby)

Matching IP V4 Address (regular expressions, ruby)

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# IP V4 Address are four decimal numbers separated by periods,
# each number ranging from 0 to 255. 

number = /(\d|[01]?\d\d|2[0-4]\d|25[0-5])/
expression = /^(#{number}\.){3}#{number}$/

sample_text = "10.123.80.202"
sample_text =~ expression

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# Extracts the keyword and the value. The assumptions are that
# the keyword oor attribute is a single word, the value extends 
# to the end of the line, and the equal sign may be surrounded 
# by whitespace.

expression = /(\w+)\s*=\s*(.*?)$/

sample_text = "color = blue"
sample_text =~ expression

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def quicksort(arr, first, last)
  return arr unless first < last
  p_index = partition(arr, first, last)
  quicksort(arr, first, p_index - 1)
  quicksort(arr, p_index + 1, last)
  arr
end

def quickselect(arr, first, last, i)
  return arr[first] if first == last

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# Andrew's monotone chain convex hull algorithm constructs the convex hull 
# of a set of 2-dimensional points in O(n\log n) time.

# It does so by first sorting the points lexicographically (first by x-coordinate, 
# and in case of a tie, by y-coordinate), and then constructing upper and lower 
# hulls of the points inO(n) time.

# An upper hull is the part of the convex hull, which is visible from the above. 
# It runs from its rightmost point to the leftmost point in counterclockwise order. 
# Lower hull is the remaining part of the convex hull.

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Rat In A Maze Puzzle (backtracking, ruby)

N-queens problem (backtracking, ruby)

Knight’s Tour Problem (backtracking, ruby)

Dijkstra Shortest Path Algorithm (paths, ruby)

Andrew's monotone chain convex hull algorithm (incremental, ruby)