Run Length 圧縮

run_length_compress.rb

require 'minitest/autorun'

class CompressString
  def initialize(text)
    @text = text
  end

  def text
    @text
  end

  def compress
    compressed = []
    chars = text.chars
    current = chars.first
    count = 0

    chars.each.with_index do |char, i|
      if current == char
        count += 1
      else
        current = char
        count = 1
      end

      compressed << [current, count] if char != chars[i+1]
    end

    compressed.flatten.join
  end
end

class CompressStringText < Minitest::Test
  def test_compress
    input = 'RRRRRRABDDDDDGG'
    expected = 'R6A1B1D5G2'
    cs = CompressString.new(input)

    assert_equal expected, cs.compress
  end
end