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sumanta.ch |
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/*
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connectk -- a program to play the connect-k family of games
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Copyright (C) 2007 Jeff Deitch
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "config.h"
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#include <glib.h>
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#include <string.h>
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#include "../shared.h"
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int utility_upper_bound;
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/* arrays for holding the utility and threat values for each window */
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int white_window_sequence_array[MAX_BOARD_SIZE][MAX_BOARD_SIZE][4];
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int black_window_sequence_array[MAX_BOARD_SIZE][MAX_BOARD_SIZE][4];
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int white_window_threat_array[MAX_BOARD_SIZE][MAX_BOARD_SIZE][4];
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int black_window_threat_array[MAX_BOARD_SIZE][MAX_BOARD_SIZE][4];
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/* arrays for holding the marks used for counting threats */
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int whites_marks[MAX_BOARD_SIZE][MAX_BOARD_SIZE];
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int blacks_marks[MAX_BOARD_SIZE][MAX_BOARD_SIZE];
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/* the sum of all the windows' values for threats and utility */
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int white_window_sequence_count;
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int black_window_sequence_count;
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int white_threat_count;
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int black_threat_count;
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/* the max sequence on a board */
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int max_white_sequence;
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int max_black_sequence;
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/* Returns an integer to identify the window */
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static int window_id(BCOORD x, BCOORD y, int i)
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{
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return x * board_size * 4 + y * 4 + i + 1;
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}
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static void clear_all()
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{
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/* clears all values in the matricies that hold the window scores and threat info */
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int x, y, d;
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for (x = 0; x < board_size; x++) {
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for (y = 0; y < board_size; y++) {
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blacks_marks[x][y] = 0;
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whites_marks[x][y] = 0;
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for (d = 0; d < 4; d++) {
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white_window_sequence_array[x][y][d] = 0;
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black_window_sequence_array[x][y][d] = 0;
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white_window_threat_array[x][y][d] = 0;
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black_window_threat_array[x][y][d] = 0;
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}
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}
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}
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white_window_sequence_count = 0;
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black_window_sequence_count = 0;
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white_threat_count = 0;
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black_threat_count = 0;
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max_black_sequence = 0;
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max_white_sequence = 0;
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}
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/* A utility function of a particular window for a given player */
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static void window_sequence(const Board *b, BCOORD x, BCOORD y, int i, PIECE player)
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{
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int sequence, count_sequence, count_threat, dx, dy, ddx, ddy, j, len;
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int ddxs[] = {1, 0, 1, 1};
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int ddys[] = {0, 1, 1, -1};
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int to_mark[MAX_CONNECT_K];
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ddx = ddxs[i];
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ddy = ddys[i];
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len = 0;
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count_sequence = 0;
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count_threat = 0;
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sequence = 0;
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if (player == PIECE_WHITE) {
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// We are recalculating this window's threat level.
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// Start be taking this window's previous threat out of the sum
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// and reset it to 0.
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white_threat_count -= white_window_threat_array[x][y][i];
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white_window_threat_array[x][y][i] = 0;
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// Do the same for the sequence count.
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white_window_sequence_count -= white_window_sequence_array[x][y][i];
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white_window_sequence_array[x][y][i] = 0;
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// step through the window.
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for (dx = 0, dy = 0; dx < connect_k && dy < (int)connect_k; dx += ddx, dy += ddy) {
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if (x + dx < 0 || y + dy < 0 || x + dx >= board_size || y + dy >= board_size) {
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break;
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}
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// If this window was the one that marked this spot, unmark it so we can recheck.
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if (whites_marks[x + dx][y + dy] == window_id(x, y, i)) {
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whites_marks[x + dx][y + dy] = 0;
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}
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if (piece_at(b, x + dx, y + dy) == PIECE_NONE) {
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count_sequence++;
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if (whites_marks[x + dx][y + dy] == 0) {
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count_threat++;
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to_mark[len++] = x + dx;
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to_mark[len++] = y + dy;
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}
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} else if (piece_at(b, x + dx, y + dy) == player) {
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count_sequence++;
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count_threat++;
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sequence++;
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}
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}
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if (count_threat == connect_k) {
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/* if this is a threat, update the threat array */
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if (sequence >= (connect_k - place_p)) {
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for (j = 0; j < len; j+=2) {
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whites_marks[to_mark[j]][to_mark[j+1]] = window_id(x, y, i);
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}
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white_window_threat_array[x][y][i] = 1;
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white_threat_count += 1;
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}
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}
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if (count_sequence == connect_k) {
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/* if this is the max sequence of the board, update the max_sequence value */
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if (sequence > max_white_sequence) {
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max_white_sequence = sequence;
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}
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/* if the sequence is greater than connect_k - place_p, set it equal to connect_k - place_p.
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This prevents it from giving a sequence of 5 a higher score than a sequence of 4 in the default game. */
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if (sequence > (connect_k - place_p)) {
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sequence = (connect_k - place_p);
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}
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/* update the utility array values */
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white_window_sequence_array[x][y][i] = sequence * sequence;
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white_window_sequence_count += white_window_sequence_array[x][y][i];
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}
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/* Do it all again if we are black. There must be a better way to do this */
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} else if (player == PIECE_BLACK) {
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// We are recalculating this window's threat level.
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// Start be taking this window's previous threat out of the sum
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// and reset it to 0.
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black_threat_count -= black_window_threat_array[x][y][i];
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black_window_threat_array[x][y][i] = 0;
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// Do the same for the sequence count.
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black_window_sequence_count -= black_window_sequence_array[x][y][i];
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black_window_sequence_array[x][y][i] = 0;
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// step through the window.
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for (dx = 0, dy = 0; dx < connect_k && dy < (int)connect_k; dx += ddx, dy += ddy) {
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if (x + dx < 0 || y + dy < 0 || x + dx >= board_size || y + dy >= board_size) {
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break;
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}
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// If this window was the one that marked this spot, unmark it so we can recheck.
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if (blacks_marks[x + dx][y + dy] == window_id(x, y, i)) {
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blacks_marks[x + dx][y + dy] = 0;
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}
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if (piece_at(b, x + dx, y + dy) == PIECE_NONE) {
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count_sequence++;
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if (blacks_marks[x + dx][y + dy] == 0) {
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count_threat++;
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to_mark[len++] = x + dx;
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to_mark[len++] = y + dy;
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}
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} else if (piece_at(b, x + dx, y + dy) == player) {
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count_sequence++;
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count_threat++;
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sequence++;
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}
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}
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if (count_threat == connect_k) {
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/* if this is a threat, update the threat array */
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if (sequence >= (connect_k - place_p)) {
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for (j = 0; j < len; j+=2) {
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blacks_marks[to_mark[j]][to_mark[j+1]] = window_id(x, y, i);
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}
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black_window_threat_array[x][y][i] = 1;
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black_threat_count += 1;
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}
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}
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if (count_sequence == connect_k) {
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/* if this is the max sequence of the board, update the max_sequence value */
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if (sequence > max_black_sequence) {
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max_black_sequence = sequence;
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}
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/* if the sequence is greater than connect_k - place_p, set it equal to connect_k - place_p.
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This prevents it from giving a sequence of 5 a higher score than a sequence of 4 in the default game. */
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if (sequence > (connect_k - place_p)) {
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sequence = (connect_k - place_p);
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}
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/* update the utility array values */
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black_window_sequence_array[x][y][i] = sequence * sequence;
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black_window_sequence_count += black_window_sequence_array[x][y][i];
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}
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} else {
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g_debug("error in window_sequence(), unknown board turn.");
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}
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}
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int board_utility(const Board *b, PIECE player)
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/* This returns the utility value of the board
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It looks for a few things, first if the currently player is on their way to winning
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(have enough moves left in given turn to win) it returns a high utility
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second if there is a threat on this board from the other player, it gives a very low utility.
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Third, if the board is going to force a win for the player, it gives a high utility.
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If none of these are true, it adds up the utilities of all the windows and subtracts
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the sum of the utilities of the other player times the defensive constant */
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{
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int utility = 0;
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utility_upper_bound = 2 * board_size * board_size * connect_k * connect_k;
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if (b->turn == PIECE_WHITE) {
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if ((connect_k - max_white_sequence) <= (b->moves_left)) {
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utility = utility_upper_bound;
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} else if (black_threat_count) {
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utility = -utility_upper_bound - black_threat_count;
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} else if (white_threat_count > place_p) {
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utility = utility_upper_bound - 1;
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} else {
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utility = white_window_sequence_count - black_window_sequence_count;
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}
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} else if (b->turn == PIECE_BLACK) {
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if ((connect_k - max_black_sequence) <= (b->moves_left)) {
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utility = utility_upper_bound;
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} else if (white_threat_count) {
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utility = -utility_upper_bound - white_threat_count;
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} else if (black_threat_count > place_p) {
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utility = utility_upper_bound - 1;
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} else {
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utility = black_window_sequence_count - white_window_sequence_count;
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}
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} else {
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g_debug("error in board_utility(), unknown board turn.");
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}
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if (b->turn != player)
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utility = -utility;
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| 273 |
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return utility;
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}
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| 275 |
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| 276 |
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int board_update(const Board *b, PIECE player)
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{
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| 278 |
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/* scans the entire board and returns its utility */
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| 279 |
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BCOORD x, y;
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| 280 |
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int i;
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| 281 |
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| 282 |
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clear_all();
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| 283 |
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| 284 |
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for (y = 0; y < board_size; y++) {
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| 285 |
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for (x = 0; x < board_size; x++) {
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| 286 |
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for (i = 0; i < 4; i++) {
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| 287 |
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window_sequence(b, x, y, i, PIECE_WHITE);
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| 288 |
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window_sequence(b, x, y, i, PIECE_BLACK);
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| 289 |
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}
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| 290 |
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}
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| 291 |
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}
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| 292 |
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| 293 |
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return board_utility(b, player);
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| 294 |
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}
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| 295 |
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| 296 |
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int incremental_update(const Board *b, BCOORD x, BCOORD y, PIECE player)
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| 297 |
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/* only scans the windows that have been impacted by a new piece and returns the board's utility */
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| 298 |
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{
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| 299 |
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int dx, dy, ddx, ddy, i, counter;
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| 300 |
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int ddxs[] = {1, 0, 1, 1};
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| 301 |
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int ddys[] = {0, 1, 1, -1};
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| 302 |
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| 303 |
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max_black_sequence = 0;
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| 304 |
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max_white_sequence = 0;
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| 305 |
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| 306 |
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for (i = 0; i < 4; i++) {
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| 307 |
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| 308 |
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ddx = ddxs[i];
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| 309 |
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ddy = ddys[i];
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| 310 |
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| 311 |
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for (counter = 0, dx = ddx * -connect_k, dy = ddy * -connect_k;
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| 312 |
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counter < connect_k + 2;
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counter ++, dx += ddx, dy += ddy) {
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| 314 |
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if (x + dx < 0 || y + dy < 0 || x + dx >= board_size || y + dy >= board_size) {
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| 315 |
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continue;
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| 316 |
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}
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| 317 |
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| 318 |
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window_sequence(b, x + dx, y + dy, i, PIECE_WHITE);
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| 319 |
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window_sequence(b, x + dx, y + dy, i, PIECE_BLACK);
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| 320 |
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}
|
| 321 |
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}
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| 322 |
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| 323 |
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return board_utility(b, player);
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| 324 |
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}
|
| 325 |
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| 326 |
|
|
AIMoves *move_utilities(const Board *b)
|
| 327 |
|
|
{
|
| 328 |
|
|
/* creates a list of possible moves based on the sequences utility function */
|
| 329 |
|
|
AIMoves *moves = aimoves_new();
|
| 330 |
|
|
AIMove move;
|
| 331 |
|
|
|
| 332 |
|
|
moves->utility = board_update(b, b->turn);
|
| 333 |
|
|
|
| 334 |
|
|
/* create a new board */
|
| 335 |
|
|
Board *new_board;
|
| 336 |
|
|
new_board = board_new();
|
| 337 |
|
|
|
| 338 |
|
|
for (move.y = 0; move.y < board_size; move.y++) {
|
| 339 |
|
|
|
| 340 |
|
|
/* bails out if ai_stop is true */
|
| 341 |
|
|
if (ai_stop)
|
| 342 |
|
|
return moves;
|
| 343 |
|
|
|
| 344 |
|
|
for (move.x = 0; move.x < board_size; move.x++) {
|
| 345 |
|
|
|
| 346 |
|
|
if (piece_at(b, move.x, move.y) != PIECE_NONE)
|
| 347 |
|
|
continue;
|
| 348 |
|
|
|
| 349 |
|
|
/* copy the board into the new board */
|
| 350 |
|
|
board_copy(b, new_board);
|
| 351 |
|
|
/* Add the piece to the board */
|
| 352 |
|
|
place_piece(new_board, move.x, move.y);
|
| 353 |
|
|
new_board->moves_left--;
|
| 354 |
|
|
/* find the utility for this new board */
|
| 355 |
|
|
move.weight = incremental_update(new_board, move.x, move.y, new_board->turn);
|
| 356 |
|
|
|
| 357 |
|
|
aimoves_add(moves, &move);
|
| 358 |
|
|
|
| 359 |
|
|
/* undo what we did, so things are correct next time around */
|
| 360 |
|
|
place_piece_type(new_board, move.x, move.y, PIECE_NONE);
|
| 361 |
|
|
new_board->moves_left++;
|
| 362 |
|
|
incremental_update(new_board, move.x, move.y, new_board->turn);
|
| 363 |
|
|
}
|
| 364 |
|
|
}
|
| 365 |
|
|
|
| 366 |
|
|
if ((b->turn == PIECE_WHITE && black_threat_count) || (b->turn == PIECE_BLACK && white_threat_count)) {
|
| 367 |
|
|
aimoves_sort(moves);
|
| 368 |
|
|
aimoves_crop(moves, 1);
|
| 369 |
|
|
}
|
| 370 |
|
|
|
| 371 |
|
|
board_free(new_board);
|
| 372 |
|
|
|
| 373 |
|
|
return moves;
|
| 374 |
|
|
}
|
| 375 |
|
|
|
| 376 |
|
|
AIMoves *ai_sequences(const Board *b)
|
| 377 |
|
|
{
|
| 378 |
|
|
AIMoves *moves = move_utilities(b);
|
| 379 |
|
|
|
| 380 |
|
|
return moves;
|
| 381 |
|
|
}
|
