gistfile1.rb

### Problem 1
def fact(number) 
  (1..number).inject(1) { |product, n| product * n }
end

def getR(number)
  fact(number).to_s.split('').inject(0) { |sum, n| sum + n.to_i }  
end

def find_lowest_value
  value = 0
  loop do
    getR(value) == 8001 ? break : value += 1
  end
  value
end

puts find_lowest_value # 787 

### Problem 2
def standard_dev(values)
  length = values.length
  mean = (values.inject(0) { |sum, v| sum + v }) / length
  diferences = values.map { |v| (v - mean) ** 2 }
  Math.sqrt((diferences.inject(0) { |sum, v| sum + v }) / length)
end

require 'nokogiri'
require 'open-uri'

def get_paragraph_depths
  url = "http://apply.embed.ly/static/data/2.html" 
  doc = Nokogiri.HTML(open(url))
  diference = 0
  values = []
  doc.css('article').each do |article|
    diference = article.at_css('p').ancestors.size
    article.css('p').each do |paragraph|
      values << paragraph.ancestors.size - (diference - 1)
    end
  end
  values
end

values = get_paragraph_depths
p standard_dev(values) # 1.4142135623730951 

### Problem 3
# x is the frequency of the most frequently used word
# x = 900 / (1 + 1/2 + 1/3 + ... + 1/900)
def getX
  900 / (1..900).inject(0) { |sum, n| sum + 1.0 / n }
end

def getCount
  x = getX
  sum, count = 0, 1
  loop do
    sum += x / count
    break if sum >= 450
    count += 1
  end
  count
end

p getCount # 22