garden.rb

require 'active_support/core_ext/array'

class Garden
  attr_reader :layout, :for_student, :students

  def initialize(layout, students = Garden.default_students)
    @students = students
    @layout = parse(layout)
    @for_student = group_by_student
    define_student_lookups
  end

  def define_student_lookups
    students.sort.each_with_index do |name, index|
      Garden.send(:define_method, name.downcase) do
        for_student[index]
      end
    end
  end

  def group_by_student
    pods = layout.in_groups_of(2)
    number_of_students = layout.size / 4
    by_student = Array.new(number_of_students){ [] }
    pods.each_with_index do |pod, index|
      by_student[ index % number_of_students ] += pod
    end
    return by_student
  end

  def parse(layout)
    codes = layout.split("").select{|code| code != "\n"}
    codes.collect{|c| flower_for(c)}
  end

  def flower_for(code)
    {"V" => :violets,
     "C" => :clover,
     "R" => :radishes,
     "G" => :grass
    }[code]
  end

  def self.default_students
    %w(Alice Bob Charlie David Eve Fred 
       Ginny Harriet Ileana Joseph
       Kincaid Larry)
  end
end