AI > AI_Racer {
  bool verbose;
  AI_RandomWithVariation leader, overtaker;
  new Best<Submission> leadersBest;
  int discardEvery = 5000;
  int roundsSinceChange;
  
  AI_RandomWithVariation newAI() { ret new AI_RandomWithVariation; }
  
  void go {
    if (round() == 1 && leadersBest.has()) // TODO: automate this
      submit(leadersBest.get());
    else if (tossACoin()) {
      if (leader == null) leader = newAI();
      initSubAI(leader);
      Submission guess = leader.guess();
      double score = submit(guess);
      leader.updateBest(guess, score);
      leadersBest.put(guess, score);
    } else {
      if (overtaker == null) overtaker = newAI();
      initSubAI(overtaker);
      Submission guess = overtaker.guess();
      double score = submit(guess);
      overtaker.updateBest(guess, score);
      if (score > leadersBest.score()) {
        // displace leader!
        if (verbose)
          print("Overtake at " + formatScore(overtaker.best.score()) + " vs " + formatScore(leadersBest.score()));
        leader = overtaker;
        overtaker = null;
        roundsSinceChange = 0;
      } else if (roundsSinceChange++ >= discardEvery) {
        // make new overtaker
        if (verbose)
          print("Discarding overtaker at " + formatScore(overtaker.best.score()) + " vs " + formatScore(leadersBest.score()));
        overtaker = null;
        roundsSinceChange = 0;
      }
    }
  }
}