09A.md

Hash Dictionary

Suppose a hash representing a directory. All keys are strings with names for either folders or files. Keys that are folders point to nested hashes. Keys that are files point to "true". Write a function that takes such a hash and returns an array of stings with the path to each file in the hash.

Example:

files = {
  'a' => {
    'b' => {
      'c' => {
        'd' => {
          'e' => true
        },

        'f' => true
      }
    }
  }
}

file_list(files) # => ['a/b/c/d/e', 'a/b/c/f']

def file_list(hash)
  files = []

  hash.each do |item, nested_item|
    if nested_item.is_a?(Hash)
      folder = item
      nested_files = file_list(nested_item)
      nested_files.each { |file| files << "#{folder}/#{file}" }
    else
      files << item
    end
  end

  files
end