// Chips.java
// Sample solution to Lab #1 Extra Credit. Written by THC.
// Plays the game of Chips For Three.  We start with an odd number of chips
// that is congruent to 1 (mod 3).  Players take turns removing chips.
// The first player removes any number of chips from the pile, leaving at least
// half of them.  From then on, the players rotate turns, removing chips from
// the pile until it is empty.
// The number of chips removed in each turn must be at least 1 and at most
// twice the number removed by the other player in the previous turn.
// At the end of the game, we take the remainder when we divide each player's
// chips by 2.  If one player has different remainder than the other two, that's
// the winner.  Otherwise (all 3 are odd), we take the remainder when we divide
// by 3.  We must have two players with equal remainders and one player with
// a different remainder (proof below).  The player with the different remainder
// is the winner.

// Proof that when we divide the final chip values by 3, two players have equal
// remainders and one player has a different remainder:
// First, suppose all 3 have the same remainder.  Then we get the following
// contradiction: the number of chips that all 3 have sum to something congruent
// to 0 (mod 3), but the sum must be congruent to 1 (mod 3).
// Now suppose all 3 have different remainders.  Then we again get the contradiction
// that the sum is congruent to 0 (mod 3), since the remainders are 0 (mod 3),
// 1 (mod 3), and 2 (mod 3).
// The only remaining possibility is that two players have equal remainders
// and one player has a different remainder.

import java.util.Scanner;

public class Chips {
  public static void main(String[] args) {
    String response;
    Scanner input = new Scanner(System.in);

    do {
      playAGame();

      System.out.print("\n\nPlay another game? (y/n) ");
      response = input.next();
    }
    while ((response.toLowerCase()).charAt(0) == 'y');
  }

  private static void playAGame() {
    Referee official = new Referee(); // Make a new game and initialize it.
    int move; // Number of chips removed in a turn

    // The main loop makes moves until the game is over.
    while (!official.saysGameIsOver()) {
      official.describeState();
      move = official.getLegalMove();
      official.updateState(move);
    }

    // All done, so announce the winner.
    official.announceWinner();
  }
}