/* Import the Java I/O package */ import java.io.*; import AppletConsoleApp; /** * Solution to the 1998 British Informatics Olympiad exam * question 2: Tamworth Two * * Sample run : * 5 6 * 4 8 * * .......... * .......... * ...F...... * .......... * ....P..... * .......... * .......... * .......... * .......... * .......... * * O 2 * 4 10 * 1 1 * * ...*...... * .......... * ...F...... * .......... * ....P..... * .......... * .......... * .......... * .......... * *......... * * M 4 * * Farmer and pigs meet on move 3 at (5,9) * * ...*P..... * .....F.... * .......... * .......... * .......... * .......... * .......... * .......... * .......... * *......... * * X * End of sample run. * * This application that can be run either from the console * as a stand-alone application or from an in-applet * console created with the AppletConsole applet. * * Solution copyright (c) 1998 The British Informatics Olympiad (BIO). * * This program may be freely copied by persons or organisations * involved in the British Informatics Olympiad or the International * Olympiad in Informatics, on condition that no changes are made and * this notice is not altered. Distribution for profit is forbidden * unless permission is first obtained in writing from the BIO. * * This program is for educational purposes only and comes with no * warranty, implied or otherwise, as to its fitness for any purpose. * * Author: Antony Rix * Internet: http://www.christs.cam.ac.uk/bio/ * E-mail: a.rix@lineone.net * S-mail: The British Informatics Olympiad * Christ's College * Cambridge CB2 3BU * United Kingdom * * @author Antony Rix * @version 0.1 * @see AppletConsoleApp * @see AppletConsole */ class BIO98R1Q2App extends AppletConsoleApp { /** * Start the application from the command line. */ public static void main(String[] args) { BIO98R1Q2App thisApp = new BIO98R1Q2App(); thisApp.redirectStreams(System.in, System.out); thisApp.run(); } /** * Representation of the board */ int[][] board = new int[12][12]; /** * Definitions for the objects */ static int blank = 0; static int obstacle = 1; static int farmer = 2; static int pigs = 3; static int capture = 4; /** * Characters for each object */ static char[] objects = { '.', '*', 'F', 'P', '+' }; /** * Directions the pigs and farmer are moving in (default up) */ int directionPigs = 0; int directionFarmer = 0; /** * Locations of pigs and farmer */ int xPigs, yPigs, xFarmer, yFarmer; /** * Current move number */ int move = 0; /** * The implementation of this application. */ public void run() { int n, i, x, y; boolean Playing = true; /* Initialise the board */ for( x = 0; x <= 11; x++ ) for( y = 0; y <= 11; y++ ) board[x][y] = obstacle; for( x = 1; x <= 10; x++ ) for( y = 1; y <= 10; y++ ) board[x][y] = blank; try { out.println( "BIO'98 Question 2" ); /* Create a StreamTokenizer to allow us to read in the two numbers */ StreamTokenizer sin = new StreamTokenizer( in ); /* Read in initial co-ordinates */ do { out.print( "Pigs at: " ); sin.nextToken(); xPigs = (int)sin.nval; sin.nextToken(); yPigs = (int)sin.nval; if( (xPigs < 0) || (xPigs > 10) || (yPigs < 0) || (yPigs > 10) ) { out.println( "Expected location for the pigs from" ); out.println( "(1,1)-(10,10) or (0,0) to demo 2(c)" ); } } while( (xPigs < 0) || (xPigs > 10) || (yPigs < 0) || (yPigs > 10) ); if( (xPigs > 0) && (yPigs > 0) ) { /* Play the standard game, placing the pigs and farmer */ board[xPigs][yPigs] = pigs; do { out.print( "Farmer at: " ); sin.nextToken(); xFarmer = (int)sin.nval; sin.nextToken(); yFarmer = (int)sin.nval; if( (xFarmer < 1) || (xFarmer > 10) || (yFarmer < 1) || (yFarmer > 10) ) { out.println( "Expected location for the Farmer from" ); out.println( "(1,1) to (10,10)" ); } } while( (xFarmer < 1) || (xFarmer > 10) || (yFarmer < 1) || (yFarmer > 10) ); board[xFarmer][yFarmer] = farmer; showBoard(); /* Move the pigs and farmer */ while( Playing ) { sin.nextToken(); if( sin.sval.compareTo( "T" ) == 0 ) { sin.nextToken(); n = (int)sin.nval; out.println( "Enter " + n + " trees:" ); for( i = 1; i <= n; i++ ) { sin.nextToken(); x = (int)sin.nval; sin.nextToken(); y = (int)sin.nval; board[x][y] = obstacle; } showBoard(); } else if( sin.sval.compareTo( "M" ) == 0 ) { sin.nextToken(); n = (int)sin.nval; for( i = 1; i <= n; i++ ) makeMove(); showBoard(); } else if( sin.sval.compareTo( "X" ) == 0 ) { Playing = false; } else out.print( "\nUnrecognised command '" + sin.sval + "'.\n" ); } } else { xPigs = 1; yPigs = 1; board[xPigs][yPigs] = pigs; directionPigs = 0; xFarmer = 2; yFarmer = 1; board[xFarmer][yFarmer] = farmer; directionFarmer = 0; out.println( "Start:" ); showBoard(); for( i = 1; i <= 19; i++ ) { makeMove(); out.print( "After move " + move ); showBoard(); } } } catch (IOException e) { out.println("I/O failure"); }; out.println( "Program finished." ); } /** * Display the board */ void showBoard() { int x, y; out.println(); for( y = 10; y >= 1; y-- ) { for( x = 1; x <= 10; x++ ) out.print( objects[board[x][y]] ); out.println(); } out.println(); } /** * Make a move */ void makeMove() { int xPigsNew = xPigs; int yPigsNew = yPigs; int xFarmerNew = xFarmer; int yFarmerNew = yFarmer; /* Move pigs */ if( directionPigs == 0 ) yPigsNew += 1; if( directionPigs == 1 ) xPigsNew += 1; if( directionPigs == 2 ) yPigsNew -= 1; if( directionPigs == 3 ) xPigsNew -= 1; if( board[xPigsNew][yPigsNew] == obstacle ) { /* We cannot move to this point, so we rotate */ xPigsNew = xPigs; yPigsNew = yPigs; directionPigs = (directionPigs + 1) % 4; } /* and farmer */ if( directionFarmer == 0 ) yFarmerNew += 1; if( directionFarmer == 1 ) xFarmerNew += 1; if( directionFarmer == 2 ) yFarmerNew -= 1; if( directionFarmer == 3 ) xFarmerNew -= 1; if( board[xFarmerNew][yFarmerNew] == obstacle ) { xFarmerNew = xFarmer; yFarmerNew = yFarmer; directionFarmer = (directionFarmer + 1) % 4; } /* Move the pieces */ board[xPigs][yPigs] = blank; board[xFarmer][yFarmer] = blank; xPigs = xPigsNew; yPigs = yPigsNew; xFarmer = xFarmerNew; yFarmer = yFarmerNew; move++; if( (xPigs == xFarmer) && (yPigs == yFarmer) ) { out.println( "Farmer and pigs meet on move " + move + " at (" + xPigs + "," + yPigs + ")" ); board[xPigs][yPigs] = capture; } else { board[xPigs][yPigs] = pigs; board[xFarmer][yFarmer] = farmer; } } }