diff --git a/board.c b/board.c index fa3c0b4..47f75e4 100644 --- a/board.c +++ b/board.c @@ -72,6 +72,38 @@ meta_init (struct metadata *meta) } +void +board_make_links (struct board *board) +{ + for (board_pos y = 0; y < 9; ++y) + for (board_pos x = 0; x < 9; ++x) + { + struct board_element *elem = BOARD_ELEM (board, x, y); + unsigned pos = ELEM_POS (x, y); + + unsigned link_count = -1; + + /* Link column adjacents */ + for (board_pos lx = 0; lx < 9; ++lx) + if (lx != x) + board->links[pos][++link_count] = BOARD_ELEM (board, lx, y); + + /* Link column adjacents */ + for (board_pos ly = 0; ly < 9; ++ly) + if (ly != y) + board->links[pos][++link_count] = BOARD_ELEM (board, x, ly); + + /* Link quadrant adjacents */ + board_pos qx = TO_QUAD (x); + board_pos qy = TO_QUAD (y); + for (board_pos lqy = 0; lqy < 3; ++lqy) + for (board_pos lqx = 0; lqx < 3; ++lqx) + if ((lqx + qx) != x && (lqy + qy) != y) + board->links[pos][++link_count] = BOARD_ELEM (board, lqx + qx, lqy + qy); + } +} + + void board_init (struct board *board) { @@ -80,8 +112,17 @@ board_init (struct board *board) defval.potential = 0x1FF; defval.complexity = 9; - for (size_t t = 0; t < (sizeof (board->elements) / sizeof (struct board_element)); ++t) - memcpy (&board->elements[t], &defval, sizeof (struct board_element)); + for (board_pos y = 0; y < 9; ++y) + for (board_pos x = 0; x < 9; ++x) + { + struct board_element *elem = BOARD_ELEM (board, x, y); + + /* Set default state */ + memcpy (elem, &defval, sizeof (struct board_element)); + } + + + board_make_links (board); board->complexity = 9; @@ -224,6 +265,7 @@ board_set ( ); struct board_element *elem = BOARD_ELEM (board, x, y); + elem->has_value = true; elem->value = value; } @@ -257,7 +299,7 @@ board_mark ( } -void +bool board_unmark ( struct board *board, board_pos x, @@ -272,19 +314,29 @@ board_unmark ( "Attempt to mark element with value" ); - struct board_element *elem = BOARD_ELEM (board, x, y); - - if (board_is_marked (board, x, y, value)) - { - /* Shift bit to correct place and then invert first 9 bits */ - elem->potential ^= (1 << value); - --(elem->complexity); - } + return elem_unmark (BOARD_ELEM (board, x, y), value); } else ERROR("Invalid parameters to function board_unmark()"); } +bool +elem_unmark ( + struct board_element *elem, + element_value value +) +{ + if (elem_is_marked (elem, value)) + { + /* Shift bit to correct place and then invert first 9 bits */ + elem->potential ^= (1 << value); + --(elem->complexity); + } + + return elem->potential != 0; +} + + bool board_has_value ( const struct board *board, @@ -325,12 +377,22 @@ board_is_marked ( { if (is_in_bounds (x, y) && is_valid_value (value)) { - return BOARD_ELEM (board, x, y)->potential & (1 << value); + return elem_is_marked(BOARD_ELEM (board, x, y), value); } else ERROR("Invalid parameters to function board_is_marked()"); } +bool +elem_is_marked ( + const struct board_element *elem, + element_value value +) +{ + return elem->potential & (1 << value); +} + + bool board_is_valid (struct board *board) { @@ -524,32 +586,18 @@ board_place ( { if (board_meta_can_set (board, x, y, value)) { - /* Unmark x-axis */ - for (board_pos unmark_x = 0; unmark_x < 9; ++unmark_x) - if (unmark_x != x && ! board_has_value (board, unmark_x, y)) - board_unmark (board, unmark_x, y, value); + struct board_element *elem = BOARD_ELEM (board, x, y); + unsigned pos = ELEM_POS (x, y); - /* Unmark y-axis */ - for (board_pos unmark_y = 0; unmark_y < 9; ++unmark_y) - if (unmark_y != y && ! board_has_value (board, x, unmark_y)) - board_unmark (board, x, unmark_y, value); - - /* Update quad */ - board_pos quad_x = TO_QUAD (x); - board_pos quad_y = TO_QUAD (y); - - for (board_pos unmark_y = 0; unmark_y < 3; ++unmark_y) - for (board_pos unmark_x = 0; unmark_x < 3; ++unmark_x) + /* Unmark all adjacent elements */ + for (unsigned i = 0; i < 20; ++i) + if ( + ! board->links[pos][i]->has_value && + ! elem_unmark (board->links[pos][i], value) + ) { - board_pos target_x = quad_x + unmark_x; - board_pos target_y = quad_y + unmark_y; - - /* Unmark value for all unset elements in quad */ - if ( - (target_x != x || target_y != y) && - !board_has_value (board, target_x, target_y) - ) - board_unmark (board, target_x, target_y, value); + /* Unmarking potential caused element to have no potential */ + return false; } /* Set value */ @@ -585,7 +633,7 @@ board_place_speculative ( /* Create duplicate and place value */ board_copy (board, board_duplicate); - if (! board_place (board_duplicate, x, y, value) || ! board_is_valid (board_duplicate)) + if (! board_place (board_duplicate, x, y, value)) return NULL; board_refresh_complexity (board_duplicate); @@ -632,5 +680,10 @@ board_refresh_complexity (struct board *board) void board_copy (const struct board *board_from, struct board *board_to) { - memcpy (board_to, board_from, sizeof(struct board)); + /* Copy everything except the links */ + memcpy ( + board_to, + board_from, + sizeof(struct board) - sizeof (((struct board *)0)->links) + ); } diff --git a/board.h b/board.h index 5dc90f1..d2ad6d4 100644 --- a/board.h +++ b/board.h @@ -6,10 +6,13 @@ #include + +#define ELEM_POS(x, y) (((y) * 9) + (x)) + /** * Get a `struct board_element`-entry from a specified location on the board */ -#define BOARD_ELEM(board_ptr, x, y) (&(board_ptr)->elements[((y) * 9) + (x)]) +#define BOARD_ELEM(board_ptr, x, y) (&(board_ptr)->elements[ELEM_POS (x, y)]) /** * Get a `struct metadata`-entry from a specified location on the quadrand grid @@ -32,6 +35,8 @@ */ #define TO_QUAD(pos) (((pos) / 3) * 3) +struct board_element; + typedef unsigned short int board_pos; typedef unsigned char element_value; @@ -45,13 +50,9 @@ typedef unsigned char element_value; struct board_element { bool has_value : 1; /* Whether element has a decided value */ - union { - element_value value : 4; /* Value of element */ - struct { - unsigned short potential : 9; /* Bitfield of possible values */ - unsigned char complexity : 4; /* Complexity tracker */ - }; - }; + element_value value : 4; /* Value of element */ + unsigned short potential : 9; /* Bitfield of possible values*/ + unsigned char complexity : 4; /* Complexity tracker */ }; /** @@ -80,6 +81,9 @@ struct board { struct metadata meta_quad [9]; /* Quadrant metadata */ struct metadata meta_row [9]; /* Row metadata */ struct metadata meta_col [9]; /* Column metadata */ + + + struct board_element *links [81][20];/* All "connected", "adjacent" elements */ }; @@ -90,6 +94,13 @@ void meta_init (struct metadata *meta); +/* + * Just generate board element adjacency links + */ +void +board_make_links (struct board *board); + + /** * Initialize a board to a blank state with maximum complexity */ @@ -184,7 +195,7 @@ board_mark ( * * NOTE: Unmarking an element with a decied value is undefined */ -void +bool board_unmark ( struct board *board, board_pos x, @@ -192,6 +203,12 @@ board_unmark ( element_value value ); +bool +elem_unmark ( + struct board_element *elem, + element_value value +); + /** * Get whether or not an element has a decided value @@ -231,6 +248,16 @@ board_is_marked ( ); +/** + * get whether or not a given element is marked with a particular value + */ +bool +elem_is_marked ( + const struct board_element *elem, + element_value value +); + + /** * Checks if there are any pairs of board elements that share a value and * also share either a row or a column diff --git a/main.c b/main.c index 60545bf..0c8c453 100644 --- a/main.c +++ b/main.c @@ -64,7 +64,10 @@ tables_ensure_depth (struct boards_table *board_spec, unsigned long long depth) /* Allocate boards */ for (unsigned long long l = board_spec->max_depth; l < new_max; ++l) + { board_spec->board_specs[l] = malloc (sizeof (struct board)); + board_make_links (board_spec->board_specs[l]); + } /* Update max depth */ board_spec->max_depth = new_max; @@ -358,15 +361,8 @@ simplify ( ++count; - //fprintf (stderr, "Placing (%u, %u)=%u (potential=%u)\n", x, y, value, elem->potential); - if (! board_place (board, x, y, value)) - { - bool rerr = meta_has_value (BOARD_ROW (board, y), value); - bool cerr = meta_has_value (BOARD_COL (board, x), value); - bool qerr = meta_has_value (BOARD_QUAD (board, TO_QUAD (x), TO_QUAD (y)), value); - fprintf (stderr, "Error (%u, %u, %u)\n", rerr, cerr, qerr); - } + return false; } } @@ -403,7 +399,8 @@ simplify ( /* If speculative placement failed, try another value */ if (board_spec == NULL) { - board_unmark (board, x, y, value); + if (! board_unmark (board, x, y, value)) + return false; continue; } @@ -422,7 +419,8 @@ simplify ( y = 9; value = 9; } - else board_unmark (board, x, y, value); + else if (! board_unmark (board, x, y, value)) + return false; } } }