Problems calling a recursive function on a multi-dimensional nested array

Question

I am trying to split the sub-arrays if there are more than 8. I have tried calling the rps_tournament_winner function on players if it has a flattened length longer than 16 but I get a "stack too deep error".

Do I have to work on the players variable or tournament? I'm looking for a nudge in the right direction; not a complete solution.

def rps_tournament_winner(tournament)
  return rps_game_winner(tournament) if tournament.flatten.length == 4
  players = tournament.flatten(2)  

  while players.length > 1
    players = players.each_slice(2).map { |x| rps_game_winner(x) }
  end

  players[0]
end

Answer 1

I solved it using recursion

class WrongNumberOfPlayersError < StandardError ; end
class NoSuchStrategyError < StandardError ; end

def rps_game_winner(game)
  raise WrongNumberOfPlayersError unless game.length == 2
  if game[0][0].is_a?(Array) then
    winner1 = rps_game_winner(game[0])
    winner2 = rps_game_winner(game[1])
    game = [winner1, winner2]
  end
  raise NoSuchStrategyError unless /^(P|R|S){2}$/ =~ game[0][1] + game[1][1]
  case game[0][1]
    when "R"
      if game[1][1] == "P" then
        game[1]
      else
        game[0]
      end
    when "P"
      if game[1][1] == "S" then
        game[1]
      else 
        game[0]
      end
    when "S"
      if game[1][1] == "R" then
        game[1]
      else
        game[0]
      end
  end
end

def rps_tournament_winner(tournament)
  rps_game_winner(tournament)
end