Etl

atbash-cipher/README.md

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+# Atbash Cipher
+
+Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.
+
+The Atbash cipher is a simple substitution cipher that relies on
+transposing all the letters in the alphabet such that the resulting
+alphabet is backwards. The first letter is replaced with the last
+letter, the second with the second-last, and so on.
+
+An Atbash cipher for the Latin alphabet would be as follows:
+
+```plain
+Plain:  abcdefghijklmnopqrstuvwxyz
+Cipher: zyxwvutsrqponmlkjihgfedcba
+```
+
+It is a very weak cipher because it only has one possible key, and it is
+a simple monoalphabetic substitution cipher. However, this may not have
+been an issue in the cipher's time.
+
+Ciphertext is written out in groups of fixed length, the traditional group size
+being 5 letters, and punctuation is excluded. This is to make it harder to guess
+things based on word boundaries.
+
+## Examples
+- Encoding `test` gives `gvhg`
+- Decoding `gvhg` gives `test`
+- Decoding `gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt` gives `The quick brown fox jumps over the lazy dog.`
+
+* * * *
+
+For installation and learning resources, refer to the
+[exercism help page](http://exercism.io/languages/ruby).
+
+For running the tests provided, you will need the Minitest gem. Open a
+terminal window and run the following command to install minitest:
+
+    gem install minitest
+
+If you would like color output, you can `require 'minitest/pride'` in
+the test file, or note the alternative instruction, below, for running
+the test file.
+
+In order to run the test, you can run the test file from the exercise
+directory. For example, if the test suite is called
+`hello_world_test.rb`, you can run the following command:
+
+    ruby hello_world_test.rb
+
+To include color from the command line:
+
+    ruby -r minitest/pride hello_world_test.rb
+
+The test files may have the execution bit set so you may also be able to
+run it like this:
+
+    ./hello_world_test.rb
+
+## Source
+
+Wikipedia [http://en.wikipedia.org/wiki/Atbash](http://en.wikipedia.org/wiki/Atbash)
+
+## Submitting Incomplete Problems
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+

atbash-cipher/atbash_cipher.rb

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+class Atbash
+	def self.encode(plain_value)
+		plain_value.gsub!(/[ .,]/,'')
+		plain_value.downcase!
+		@array_char=('a'..'z').to_a
+		string_to_array=plain_value.split('')
+		n=0
+		cipher_text=''
+		while n != string_to_array.length
+			if string_to_array[n] =~ /[a-z]/
+			  temp_index=@array_char.index(string_to_array[n]).to_i
+			  cipher_text += @array_char[25 - temp_index]
+			else
+				cipher_text += string_to_array[n].to_s
+			end
+			n += 1
+		end
+		contain_string=''
+		temp_div=0
+		temp_array=cipher_text.split('')
+		(0...temp_array.length).each do |i|
+		  if(temp_div % 5 == 0)
+		  	contain_string += ' '
+		  end
+		  contain_string += temp_array[i]
+		  temp_div += 1
+		end
+		return contain_string.gsub!(/^[ ]+/,'') 
+
+	end
+end 

atbash-cipher/atbash_cipher_test.rb

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+#!/usr/bin/env ruby
+gem 'minitest', '>= 5.0.0'
+require 'minitest/autorun'
+require_relative 'atbash_cipher'
+
+class AtbashTest < Minitest::Test
+  def test_encode_no
+    assert_equal 'ml', Atbash.encode('no')
+  end
+
+  def test_encode_yes
+    # skip
+    assert_equal 'bvh', Atbash.encode('yes')
+  end
+
+  def test_encode_OMG
+    # skip
+    assert_equal 'lnt', Atbash.encode('OMG')
+  end
+
+  def test_encode_O_M_G
+    # skip
+    assert_equal 'lnt', Atbash.encode('O M G')
+  end
+
+  def test_encode_long_word
+    # skip
+    assert_equal 'nrmwy oldrm tob', Atbash.encode('mindblowingly')
+  end
+
+  def test_encode_numbers
+    # skip
+    assert_equal('gvhgr mt123 gvhgr mt',
+                 Atbash.encode('Testing, 1 2 3, testing.'))
+  end
+
+  def test_encode_sentence
+    # skip
+    assert_equal 'gifgs rhurx grlm', Atbash.encode('Truth is fiction.')
+  end
+
+  def test_encode_all_the_things
+    # skip
+    plaintext = 'The quick brown fox jumps over the lazy dog.'
+    cipher = 'gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt'
+    assert_equal cipher, Atbash.encode(plaintext)
+  end
+end

binary/README.md

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+# Binary
+
+Write a program that will convert a binary number, represented as a string (e.g. '101010'), to its decimal equivalent using first principles
+
+Implement binary to decimal conversion. Given a binary input
+string, your program should produce a decimal output. The
+program should handle invalid inputs.
+
+## Note
+- Implement the conversion yourself.
+  Do not use something else to perform the conversion for you.
+
+## About Binary (Base-2)
+Decimal is a base-10 system.
+
+A number 23 in base 10 notation can be understood
+as a linear combination of powers of 10:
+
+- The rightmost digit gets multiplied by 10^0 = 1
+- The next number gets multiplied by 10^1 = 10
+- ...
+- The *n*th number gets multiplied by 10^*(n-1)*.
+- All these values are summed.
+
+So: `23 => 2*10^1 + 3*10^0 => 2*10 + 3*1 = 23 base 10`
+
+Binary is similar, but uses powers of 2 rather than powers of 10.
+
+So: `101 => 1*2^2 + 0*2^1 + 1*2^0 => 1*4 + 0*2 + 1*1 => 4 + 1 => 5 base 10`.
+
+* * * *
+
+For installation and learning resources, refer to the
+[exercism help page](http://exercism.io/languages/ruby).
+
+For running the tests provided, you will need the Minitest gem. Open a
+terminal window and run the following command to install minitest:
+
+    gem install minitest
+
+If you would like color output, you can `require 'minitest/pride'` in
+the test file, or note the alternative instruction, below, for running
+the test file.
+
+In order to run the test, you can run the test file from the exercise
+directory. For example, if the test suite is called
+`hello_world_test.rb`, you can run the following command:
+
+    ruby hello_world_test.rb
+
+To include color from the command line:
+
+    ruby -r minitest/pride hello_world_test.rb
+
+The test files may have the execution bit set so you may also be able to
+run it like this:
+
+    ./hello_world_test.rb
+
+## Source
+
+All of Computer Science [http://www.wolframalpha.com/input/?i=binary&a=*C.binary-_*MathWorld-](http://www.wolframalpha.com/input/?i=binary&a=*C.binary-_*MathWorld-)
+
+## Submitting Incomplete Problems
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+

binary/binary.rb

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+class Binary
+  def self.to_decimal(binary_string)
+    if (binary_string =~ /^[01]+$/)
+      binary_string_number=binary_string.to_i
+      sum=0
+      i=0
+      while binary_string_number != 0
+        digit=binary_string_number%10
+        if(digit!=0)
+          sum+=(digit*(2**i)).to_i
+        end
+        i+=1
+        binary_string_number/=10
+      end
+      return sum
+    else
+      raise ArgumentError
+    end
+  end
+end
+module BookKeeping
+ 	VERSION=3
+end

binary/binary_test.rb

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+#!/usr/bin/env ruby
+# encoding: utf-8
+gem 'minitest', '>= 5.0.0'
+require 'minitest/autorun'
+require_relative 'binary'
+
+# Test data version:
+# 82eb00d
+class BinaryTest < Minitest::Test
+  def test_binary_0_is_decimal_0
+    # skip
+    assert_equal 0, Binary.to_decimal('0')
+  end
+
+  def test_binary_1_is_decimal_1
+    #skip
+    assert_equal 1, Binary.to_decimal('1')
+  end
+
+  def test_binary_10_is_decimal_2
+    #skip
+    assert_equal 2, Binary.to_decimal('10')
+  end
+
+  def test_binary_11_is_decimal_3
+    #skip
+    assert_equal 3, Binary.to_decimal('11')
+  end
+
+  def test_binary_100_is_decimal_4
+    #skip
+    assert_equal 4, Binary.to_decimal('100')
+  end
+
+  def test_binary_1001_is_decimal_9
+    #skip
+    assert_equal 9, Binary.to_decimal('1001')
+  end
+
+  def test_binary_11010_is_decimal_26
+    #skip
+    assert_equal 26, Binary.to_decimal('11010')
+  end
+
+  def test_binary_10001101000_is_decimal_1128
+    #skip
+    assert_equal 1128, Binary.to_decimal('10001101000')
+  end
+
+  def test_binary_ignores_leading_zeros
+    #skip
+    assert_equal 31, Binary.to_decimal('000011111')
+  end
+
+  def test_2_is_not_a_valid_binary_digit
+    #skip
+    assert_raises(ArgumentError) { Binary.to_decimal('2') }
+  end
+
+  def test_a_number_containing_a_non_binary_digit_is_invalid
+    #skip
+    assert_raises(ArgumentError) { Binary.to_decimal('01201') }
+  end
+
+  def test_a_number_with_trailing_non_binary_characters_is_invalid
+    #skip
+    assert_raises(ArgumentError) { Binary.to_decimal('10nope') }
+  end
+
+  def test_a_number_with_leading_non_binary_characters_is_invalid
+    #skip
+    assert_raises(ArgumentError) { Binary.to_decimal('nope10') }
+  end
+
+  def test_a_number_with_internal_non_binary_characters_is_invalid
+    #skip
+    assert_raises(ArgumentError) { Binary.to_decimal('10nope10') }
+  end
+
+  def test_a_number_and_a_word_whitespace_spearated_is_invalid
+    #skip
+    assert_raises(ArgumentError) { Binary.to_decimal('001 nope') }
+  end
+  # Problems in exercism evolve over time, as we find better ways to ask
+  # questions.
+  # The version number refers to the version of the problem you solved,
+  # not your solution.
+  #
+  # Define a constant named VERSION inside of the top level BookKeeping
+  # module, which may be placed near the end of your file.
+  #
+  # In your file, it will look like this:
+  #
+  # module BookKeeping
+  #   VERSION = 1 # Where the version number matches the one in the test.
+  # end
+  #
+  # If you are curious, read more about constants on RubyDoc:
+  # http://ruby-doc.org/docs/ruby-doc-bundle/UsersGuide/rg/constants.html
+  def test_bookkeeping
+    #skip
+    assert_equal 3, BookKeeping::VERSION
+  end
+end

difference-of-squares/README.md

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+# Difference Of Squares
+
+Find the difference between the sum of the squares and the square of the sums of the first N natural numbers.
+
+The square of the sum of the first ten natural numbers is,
+
+    (1 + 2 + ... + 10)**2 = 55**2 = 3025
+
+The sum of the squares of the first ten natural numbers is,
+
+    1**2 + 2**2 + ... + 10**2 = 385
+
+Hence the difference between the square of the sum of the first
+ten natural numbers and the sum of the squares is 2640:
+
+    3025 - 385 = 2640
+
+* * * *
+
+For installation and learning resources, refer to the
+[exercism help page](http://exercism.io/languages/ruby).
+
+For running the tests provided, you will need the Minitest gem. Open a
+terminal window and run the following command to install minitest:
+
+    gem install minitest
+
+If you would like color output, you can `require 'minitest/pride'` in
+the test file, or note the alternative instruction, below, for running
+the test file.
+
+In order to run the test, you can run the test file from the exercise
+directory. For example, if the test suite is called
+`hello_world_test.rb`, you can run the following command:
+
+    ruby hello_world_test.rb
+
+To include color from the command line:
+
+    ruby -r minitest/pride hello_world_test.rb
+
+The test files may have the execution bit set so you may also be able to
+run it like this:
+
+    ./hello_world_test.rb
+
+## Source
+
+Problem 6 at Project Euler [http://projecteuler.net/problem=6](http://projecteuler.net/problem=6)
+
+## Submitting Incomplete Problems
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+