// Tic Tac Toe solution.
// Date: 27 Feb 2001
// Author: Rimon Barr

import java.io.*;

class TicTacToe {

  // constants for player pieces and numbers
  private static final char PL1C='X', PL2C='O', EMPTY=' ';
  private static final int PL1N=1, PL2N=2;

  // board variables (row, col)
  private static char sq11,sq12,sq13, sq21,sq22,sq23, sq31,sq32,sq33;

  // input stream
  private static BufferedReader in=
    new BufferedReader(new InputStreamReader(System.in));

  // display board
  public static void printBoard() {
    System.out.println("+---+---+---+");
    System.out.println("| "+sq11+" | "+sq12+" | "+sq13+" |");
    System.out.println("+---+---+---+");
    System.out.println("| "+sq21+" | "+sq22+" | "+sq23+" |");
    System.out.println("+---+---+---+");
    System.out.println("| "+sq31+" | "+sq32+" | "+sq33+" |");
    System.out.println("+---+---+---+");
  }

  // reset the board
  public static void clearBoard() {
    sq11=EMPTY; sq12=EMPTY; sq13=EMPTY;
    sq21=EMPTY; sq22=EMPTY; sq23=EMPTY;
    sq31=EMPTY; sq32=EMPTY; sq33=EMPTY;
  }

  // determine whether position within board limits
  public static boolean isValidPos(String s) {
    return s!=null && s.length()==2 && 
      s.charAt(0)>='1' && s.charAt(0)<='3' &&
      s.charAt(1)>='1' && s.charAt(1)<='3';
  }

  // convert string position representation to integer
  public static int convertStringPosToNumber(String sPos) {
    return 10*(sPos.charAt(0)-'0') + sPos.charAt(1)-'0';
  }

  // return piece at board position
  public static char getBoard(int pos) {
    switch (pos) {
      case 11: return sq11;
      case 12: return sq12;
      case 13: return sq13;
      case 21: return sq21;
      case 22: return sq22;
      case 23: return sq23;
      case 31: return sq31;
      case 32: return sq32;
      case 33: return sq33;
      default: return EMPTY;
    }
  }

  // set a square on the board to given piece
  public static void setBoard(int pos, char piece) {
    switch (pos) {
      case 11: sq11=piece; break;
      case 12: sq12=piece; break;
      case 13: sq13=piece; break;
      case 21: sq21=piece; break;
      case 22: sq22=piece; break;
      case 23: sq23=piece; break;
      case 31: sq31=piece; break;
      case 32: sq32=piece; break;
      case 33: sq33=piece; break;
    }
  }

  // determine whether the board is filled
  public static boolean isBoardFull() {
    return sq11!=EMPTY && sq12!=EMPTY && sq13!=EMPTY &&
      sq21!=EMPTY && sq22!=EMPTY && sq23!=EMPTY &&
      sq31!=EMPTY && sq32!=EMPTY && sq33!=EMPTY;
  }

  // check if a given player has won
  public static boolean hasPlayerWon(char player) {
    // columns
    if (sq11==player && sq21==player && sq31==player) return true;
    if (sq12==player && sq22==player && sq32==player) return true;
    if (sq13==player && sq23==player && sq33==player) return true;
    // rows
    if (sq11==player && sq12==player && sq13==player) return true;
    if (sq21==player && sq22==player && sq23==player) return true;
    if (sq31==player && sq32==player && sq33==player) return true;
    // diagonals
    if (sq11==player && sq22==player && sq33==player) return true;
    if (sq31==player && sq22==player && sq13==player) return true;
    // exhausted all winning possibilities
    return false;
  }

  // determine if the game is over
  public static boolean isGameOver() {
    return isBoardFull() || hasPlayerWon(PL1C) || hasPlayerWon(PL2C);
  }

  // play one game
  public static boolean playGame() {
    System.out.println("New Game.");
    // variables for input and turn counter
    String input="";
    int turnCounter=0;
    // reset board
    clearBoard();
    // play game until its over or user asks to quit
    while (!isGameOver() && !input.equals("99")) {
      // display board
      printBoard();
      // set pln and plc according to turn
      int pln;
      char plc;
      if (turnCounter%2==0) {
        plc=PL1C;
        pln=PL1N;
      }
      else {
        plc=PL2C;
        pln=PL2N;
      }
      // ask for input
      System.out.print("Player "+pln+" turn: ");
      try {
        input=in.readLine();
      }
      catch (IOException e) {
        input="99";
      }
      // check that position is valid
      if (!isValidPos(input)) {
        System.out.println("Invalid position.");
        continue;
      }
      int pos=convertStringPosToNumber(input);
      // check that position is empty
      if (getBoard(pos)!=EMPTY) {
        System.out.println("Position already taken. Please try again.");
        continue;
      }
      // put piece on board
      setBoard(pos, plc);
      // increment turn counter
      turnCounter++;
    }
    // determine how the game ended
    printBoard();
    if (hasPlayerWon(PL1C))
      System.out.println("Player "+PL1N+" won.");
    else if (hasPlayerWon(PL2C))
      System.out.println("Player "+PL2N+" won.");
    else if (isBoardFull())
      System.out.println("Draw.");
    else {
      System.out.println("Game not completed.");
      return false; // do not play another game
    }
    return true; // play another game
  }

  // program entry point
  public static void main(String[] args) {
    // introduction
    System.out.println("Welcome to Tic Tac Toe.");
    System.out.println("Please enter positions as 'rc' (r - row, c - col), or 99 to exit");
    // play loop
    while(playGame());
    // say goodbye
    System.out.println("Thanks for playing. Come again.");
  }
}