iterative_brute.rb

require 'pp'

def perms(s)
  base = [s.downcase, s.upcase]
  case s.downcase
  when 'a'
    base << '@'
  when 'o'
    base << '0'
  when 'e'
    base << '3'
  when 'i'
    base << '!'
  end
  base
end

def combine(arr1, arr2)
  output = []
  arr1.each do |a1|
    arr2.each do |a2|
      output << "#{a1}#{a2}"
    end
  end
  output
end

def guess(string)
  string = string.split("") if string.is_a?(String)
  start = perms string.shift
  string.each do |l|
    start = combine(start, perms(l))
  end
  start
end


puts guess("jamster")

monkey_patched.rb

def perms(s)
  base = [s.downcase, s.upcase]
  case s.downcase
  when 'a'
    base << '@'
  when 'o'
    base << '0'
  when 'e'
    base << '3'
  when 'i'
    base << '!'
  end
  base
end

class Array
  def *(array)
    output = []
    return array if self.length == 0
    self.each do |a1|
      array.each do |a2|
        output << "#{a1}#{a2}"
      end
    end
    output
  end
end

def guess(string)
  string.split("").map{|s| perms(s) }.inject([]){|results, elem| results = results * elem}   
end

puts guess 'jamster'

recursive_brute.rb

require "benchmark"

def perms(s)
  base = [s.downcase, s.upcase]
  case s.downcase
  when 'a'
    base << '@'
  when 'o'
    base << '0'
  when 'e'
    base << '3'
  when 'i'
    base << '!'
  end
  base
end

def combine(arr1, arr2)
  output = []
  arr1.each do |a1|
    arr2.each do |a2|
      output << "#{a1}#{a2}"
    end
  end
  output
end

class Array
  def blank?
    self.length == 0
  end
end

def guess(letters, solution=[])
  letters = letters.split('') if letters.is_a?(String)
  next_letter = letters.shift
  if solution.blank?
    return guess(letters, perms(next_letter))
  elsif !next_letter.nil?
    return guess(letters, combine(solution, perms(next_letter)))
  else
    return solution
  end
end

# when does it get crazy long

# letters = ('a'..'z').to_a
# Benchmark.bmbm do |results|
#     (0..25).to_a.each do |i|
#       string = letters[0..i].join("")
#       results.report(string) do
#         output =  guess(string)
#         puts output.length
#       end
#     end
# end


puts guess('jamster')