recursive_conv_array_to_hash.rb

def recursive_conv_array_to_hash(h)
  h.each{|key, value|
   if value.is_a?(Array)
     hh = {}
     value.each{|e| hh[e]=0 }
     h[key] = hh
   else
    recursive_conv_array_to_hash value
   end
  }
end

h = {'a'=>{'aa'=>['aaa','aab']}, 'b'=>['bb','bc']}
puts h
recursive_conv_array_to_hash h
puts h