rockbox/apps/plugins/reversi/reversi-strategy-simple.c
Antoine Cellerier cd82964e5d Make sure that reversi doesn't enter an infinite loop when using 1 or 2 AIs.
+ some changes that will be needed for more advanced AIs (which aren't ready to commit yet)


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@13758 a1c6a512-1295-4272-9138-f99709370657
2007-07-01 20:48:51 +00:00

118 lines
3.5 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (c) 2007 Antoine Cellerier
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "reversi-strategy.h"
/**
* Simple strategy:
* A very simple strategy. Makes the highest scoring move taking the other
* player's next best move into account.
* From Algorithm by Claudio Clemens in hinversi, simpleClient.c
*/
static void reversi_copy_board(reversi_board_t *dst,
const reversi_board_t *src) {
int i;
dst->rb = src->rb;
dst->rb->memcpy(dst->history,src->history,
(BOARD_SIZE*BOARD_SIZE - INIT_STONES)*sizeof(move_t));
for(i=0;i<BOARD_SIZE;i++) {
dst->rb->memcpy(dst->board[i],src->board[i],BOARD_SIZE*sizeof(int));
}
}
static int reversi_sim_move(const reversi_board_t *game, const int row,
const int col, const int player) {
reversi_board_t game_clone;
reversi_copy_board(&game_clone,game);
return reversi_make_move(&game_clone,row,col,player);
}
static int reversi_get_max_moves(const reversi_board_t *game, int player) {
int max = -BOARD_SIZE*BOARD_SIZE;
int row, col;
for(row=0; row<BOARD_SIZE; row++) {
for(col=0; col<BOARD_SIZE; col++) {
int v = reversi_sim_move(game,row,col,player);
if(v>max)
max = v;
}
}
return max;
}
static int reversi_sim_move2(const reversi_board_t *game, const int row,
const int col, const int player) {
/* Takes the other player's next best move into account */
int score;
reversi_board_t game_clone;
reversi_copy_board(&game_clone,game);
score = reversi_make_move(&game_clone,row,col,player);
return score - reversi_get_max_moves(&game_clone,
reversi_flipped_color(player));
}
static move_t simple_move_func(const reversi_board_t *game, int player) {
int max = -BOARD_SIZE*BOARD_SIZE;
int count = 0;
int row, col;
int r;
for(row=0; row<BOARD_SIZE; row++) {
for(col=0; col<BOARD_SIZE; col++) {
int v = reversi_sim_move2(game,row,col,player);
if(v>max) {
max = v;
count = 1;
}
else if(v==max) {
count ++;
}
}
}
if(!count) return MOVE_INVALID;
/* chose one of the moves which scores highest */
r = game->rb->rand()%count;
row = 0;
col = 0;
while(true) {
if(reversi_sim_move2(game, row, col, player)==max) {
r--;
if(r<0) {
return MAKE_MOVE(row,col,player);
}
}
col ++;
if(col==BOARD_SIZE) {
col = 0;
row ++;
if(row==BOARD_SIZE) {
row = 0;
}
}
}
}
const game_strategy_t strategy_simple = {
true,
NULL,
simple_move_func
};