dmill

class PerfectNumber

  def self.classify(num)
    raise RuntimeError if num < 1

    aliquot_sum = (1..(num / 2)).select {|int| num % int == 0}.reduce(:+)

    if aliquot_sum > num
      "abundant"
    elsif aliquot_sum < num

dmill

Perfect Numbers

Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for natural numbers.

The Greek mathematican Nicomachus devised a classification scheme for natural numbers, identifying each as belonging uniquely to the categories of perfect, abundant, or deficient based on their aliquot sum. The aliquot sum is defined as the sum of the factors of a number not including the number itself. For example, the aliquot sum of 15 is (1 + 3 + 5) = 9

• Perfect: aliquot sum = number
  • 6 is a perfect number because (1 + 2 + 3) = 6
  • 28 is a perfect number because (1 + 2 + 4 + 7 + 14) = 28
• Abundant: aliquot sum > number

dmill

class Main {
	public static void main(String[] args) {
		for(int num = 1; num <= 100; num++)
			System.out.println(convertToRoman(num));
	}
		
	public static String convertToRoman(int num) {
		String number =  "";
		int M, D, C, L, X, V, I;
		M = D = C = L = X = V = I = 0;

dmill

Roman Numerals

Write a function to convert from normal numbers to Roman Numerals.

The Romans were a clever bunch. They conquered most of Europe and ruled it for hundreds of years. They invented concrete and straight roads and even bikinis. One thing they never discovered though was the number zero. This made writing and dating extensive histories of their exploits slightly more challenging, but the system of numbers they came up with is still in use today. For example the BBC uses Roman numerals to date

dmill

require "benchmark"

class Prime

  def self.nth(num)
    raise ArgumentError if num == 0 || num.class != Fixnum
    count = 0
    check = 1

    while count != num

dmill

class Prime
  def nth(num)
  end
end

dmill

class PhoneNumber

  def initialize(raw_string)
    @clean_string = raw_string.gsub(/[\(\)\-\s\.]/, "")
    @clean_string[0] = "" if @clean_string[0] == "1" && @clean_string.length == 11
  end

  def number
    valid_clean_string? ? @clean_string : '0000000000'
  end

dmill

Phone Number

Clean up user-entered phone numbers so that they can be sent SMS messages.

The rules are as follows:

• If the phone number is less than 10 digits assume that it is bad number
• If the phone number is 10 digits assume that it is good
• If the phone number is 11 digits and the first number is 1, trim the 1

dmill

 def return_all_file_names_and_paths(username, repo, path = nil, files = {})
      uri_string = "https://api.github.com/repos/#{username}/#{repo}/contents/#{path}"
      root_directory = make_api_call(uri_string)

      root_directory.each do |item|
        if item["type"] == "file"
          files[item["name"]] = item["path"]
        elsif item["type"] == "dir"
          return_all_file_names_and_paths(username, repo, item["path"], files )
        end

dmill

//point 1 and point 2 are arrays representing tuples of x,y coordinates.
function distance(point1, point2) {
  return Math.sqrt(Math.pow((point1[0] - point2[0]), 2) + Math.pow((point1[1] - point2[1]), 2))
}

// a and b are driver 1's starting and ending locations, in the form of arrays representing tuples
//of x,y coordinates. c and d similarly correspond to driver 2. Returns the shorter overall trip.
function shortestTrip (a,b,c,d) {
  var driver1Distance = distance(a,c) + distance(c,d) + distance(c,b)
  var driver2Distance = distance(c,a) + distance(a,b) + distance(b,d)