Find string pairs puzzlers http://java.dzone.com/articles/thursday-code-puzzler-find-1

gistfile1.rb

require 'minitest/autorun'

class StringPairsFinder
  def find(s)
	  return if s.nil?

    tokens = s.split
    result = Result.new

    tokens.each_with_index do |t,i|
      comb = result.find_or_create_comb(t)

      tokens[i+1..tokens.size].each_with_index do |t1, i1|
        if t == t1
          pair = Pair.new
          pair.idx1 = i
          pair.idx2 = (i+ i1) + 1
          comb << pair
        end
      end
    end
    result
  end
end

class Result
  attr_accessor :combinations

  def initialize
    @combinations = {}
  end

  def find_by_word(w)
    combinations[w]
  end

  def find_or_create_comb(w)
    if c = combinations[w]
      c
    else
      combinations[w] = Combination.new w
    end
  end
end

class Combination
  attr_accessor :pairs, :word

  def initialize(word)
    @pairs = []
    @word = word
  end

  def <<(e)
    pairs << e
  end

  def find_adjacent
    pairs.find_all {|p| p.adjacent? }
  end
end

class Pair
  attr_accessor :idx1, :idx2

  def initialize
    @idx1 = 0
    @idx2 = 0
  end

  def to_s
    "(#{idx1},#{idx2})"
  end

  def inspect
    to_s
  end

  def adjacent?
    (idx1 + 1) == idx2
  end
end

class TestStringPairsFinder < MiniTest::Unit::TestCase
  attr_reader :finder

   def setup
     @finder = StringPairsFinder.new	
   end

   def test_string_pairs_finder
    s = "dzone java dzone dzone javascript java"
    result = finder.find(s)

    assert(result)

    assert_equal(3, result.combinations.size)
    dzone_comb = result.find_by_word("dzone")
    java_comb = result.find_by_word("java")

    assert_equal(3, dzone_comb.pairs.size)
    assert_equal("[(0,2), (0,3), (2,3)]", dzone_comb.pairs.inspect)
    assert_equal("(2,3)", dzone_comb.find_adjacent.first.inspect)
    assert_equal(1, java_comb.pairs.size)
    assert_equal("(1,5)", java_comb.pairs.first.inspect)
  end
end

# dzone has 1 adjacent pair
# dzone has 3 combination pairs (0,2) (0,3) (2,3)
# java has 1 combination pair (1,5)