static int openregion(struct board_lib_state_struct *internal_state, int i1, int i2, int j1, int j2) { int x, y; if (i1 > i2) return openregion(internal_state, i2, i1, j1, j2); if (j1 > j2) return openregion(internal_state, i1, i2, j2, j1); /* Disregard parts of the region off the board. This is convenient * in order not to have to special-case tiny boards. It also secures * against potential reading outside the board[] array boundaries. */ if (i1 < 0) i1 = 0; if (j1 < 0) j1 = 0; if (i2 >= internal_state->board_size) i2 = internal_state->board_size - 1; if (j2 >= internal_state->board_size) j2 = internal_state->board_size - 1; for (x = i1; x <= i2; x++) for (y = j1; y <= j2; y++) if (BOARD(x, y) != EMPTY) return 0; return 1; }
static int openregion(int i1, int i2, int j1, int j2) { int x, y; if (i1 > i2) return openregion(i2, i1, j1, j2); if (j1 > j2) return openregion(i1, i2, j2, j1); for (x = i1; x <= i2; x++) for (y = j1; y <= j2; y++) if (BOARD(x, y) != EMPTY) return 0; return 1; }
int findpatn(int *i, int *j, int *val) /* find pattern to match for next move */ { int m, n; int ti, tj, tval; static int cnd, mtype; /* game tree node number, move type */ /* mtype = 0, basic; 1, inverted; 2, reflected; 3, inverted & reflected */ /* open game then occupy corners */ if (opn[4]) /* continue last move */ { opn[4] = 0; /* clear flag */ if (opening(i, j, &cnd, mtype)) opn[4] = 1; /* more move then reset flag */ if (p[*i][*j] == EMPTY) /* valid move */ { *val = 80; return 1; } else opn[4] = 0; } if (opn[0]) /* Northwest corner */ { opn[0] = 0; /* clear flag */ if (openregion(0, 0, 5, 5)) { cnd = 0; mtype = 0; opening(i, j, &cnd, mtype); /* get new node for next move */ if (opening(i, j, &cnd, mtype)) opn[4] = 1; *val = 80; return 1; } } if (opn[1]) /* Southwest corner */ { opn[1] = 0; if (openregion(13, 0, 18, 5)) { cnd = 0; mtype = 1; opening(i, j, &cnd, mtype); /* get new node for next move */ if (opening(i, j, &cnd, mtype)) opn[4] = 1; *val = 80; return 1; } } if (opn[2]) /* Northeast corner */ { opn[2] = 0; if (openregion(0, 13, 5, 18)) { cnd = 0; mtype = 2; opening(i, j, &cnd, mtype); /* get new node for next move */ if (opening(i, j, &cnd, mtype)) opn[4] = 1; *val = 80; return 1; } } if (opn[3]) /* Northeast corner */ { opn[3] = 0; if (openregion(13, 13, 18, 18)) { cnd = 0; mtype = 3; opening(i, j, &cnd, mtype); /* get new node for next move */ if (opening(i, j, &cnd, mtype)) opn[4] = 1; *val = 80; return 1; } } /* occupy edges */ if (opn[5]) /* North edge */ { opn[5] = 0; if (openregion(0, 6, 4, 11)) { *i = 3; *j = 9; *val = 80; return 1; } } if (opn[6]) /* South edge */ { opn[6] = 0; if (openregion(18, 6, 14, 11)) { *i = 15; *j = 9; *val = 80; return 1; } } if (opn[7]) /* West edge */ { opn[7] = 0; if (openregion(6, 0, 11, 4)) { *i = 9; *j = 3; *val = 80; return 1; } } if (opn[8]) /* East edge */ { opn[8] = 0; if (openregion(6, 18, 11, 14)) { *i = 9; *j = 15; *val = 80; return 1; } } *i = -1; *j = -1; *val = -1; /* find local pattern */ for (m = 0; m < 19; m++) for (n = 0; n < 19; n++) if ((p[m][n] == mymove) && (matchpat(m, n, &ti, &tj, &tval) && (tval > *val))) { *val = tval; *i = ti; *j = tj; } if (*val > 0) /* pattern found */ return 1; else /* no match found */ return 0; } /* end findpatn */
/* Generate move in empty corner or in middle of small board.*/ void fuseki(int color) { int i = -1; int j = -1; int width; /* Side of the open region required in the corner. */ int empty_corner_value = EMPTY_CORNER_VALUE * board_size/19; /* Return immediately if --disable_fuseki option used. */ if (disable_fuseki) return; set_symmetries(); /* Search in fuseki database unless disabled by --nofusekidb option. */ if (fusekidb && search_fuseki_database(color)) return; /* On 9x9, only play open corners after the first move if nothing * else useful is found. */ if (board_size == 9 && stones_on_board(color) > 0) empty_corner_value = 5; if (board_size <= 11) { /* For boards of size 11x11 or smaller we first go for the center point. */ int middle = board_size/2; if (openregion(middle-2, middle+2, middle-2, middle+2)) { announce_move(POS(middle, middle), 45, color); } } if (board_size < 9) return; if (board_size >= 18) width = 8; else if (board_size == 9) width = 5; else width = board_size/2; if (openregion(0, width-1, board_size-width, board_size-1)) { choose_corner_move(UPPER_RIGHT, &i, &j); announce_move(POS(i, j), empty_corner_value, color); } if (openregion(board_size-width, board_size-1, 0, width-1)) { choose_corner_move(LOWER_LEFT, &i, &j); announce_move(POS(i, j), empty_corner_value, color); } if (openregion(board_size-width, board_size-1, board_size-width, board_size-1)) { choose_corner_move(LOWER_RIGHT, &i, &j); announce_move(POS(i, j), empty_corner_value, color); } if (openregion(0, width-1, 0, width-1)) { choose_corner_move(UPPER_LEFT, &i, &j); announce_move(POS(i, j), empty_corner_value, color); } }