def person_is_seller?(name)
  name[-1] == "m"
end

@graph = {}

# %w(string1 string2 ...) is a shorter way to define arrays of strings
@graph["you"] = %w(alice bob claire)
@graph["bob"] = %w(anuj peggy)
@graph["alice"] = %w(peggy)
@graph["claire"] = %w(thom jonny)
@graph["anuj"] = []
@graph["peggy"] = []
@graph["thom"] = []
@graph["jonny"] = []

def search(name)
  search_queue = []
  search_queue += @graph[name]
  # This array is how you keep track of which people you've searched before.
  searched = []

  until search_queue.empty?
    person = search_queue.shift
    # Only search this person if you haven't already searched them.
    next if searched.member?(person)
    return person if yield person
    search_queue += @graph[person]
      # Marks this person as searched
    searched.push(person)
  end

  false
end

search("you"){|person| person_is_seller?(person) }.tap{|person| puts "#{person} is a mango seller!" if person}