abstract sclass AIStrategy<A> implements Steppable {
  F1<A, Double> submit; // returns score
  int round;
  new Best<A> best;
  
  void updateBest(A guess, double score) {
    best.put(guess, score);
  }
  
  A submit(A guess) {
    if (guess != null)
      best.put(guess, callF(submit, guess));
    ret guess;
  }
}