Start implementing metadata analysis
This commit is contained in:
Gabriel Tofvesson
parent
98de45e928
commit
83e2d0f3e3
259
board.c
259
board.c
@ -20,6 +20,20 @@
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}
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/**
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* Raises an error if the given condition is not met
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* The error will be the given reason
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*/
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#ifdef OPTIMIZE
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#define ASSERT(cond, reason)
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#else
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#define ASSERT(cond, reason) \
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{ \
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if (! cond) ERROR ((reason)); \
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}
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#endif
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/**
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* Check if a given xy-pair is in bounds of a Sudoku board
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*/
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@ -51,11 +65,139 @@ is_valid_value (element_value value)
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}
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void
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meta_init (struct metadata *meta)
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{
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memset (meta, 0, sizeof (struct metadata));
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}
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void
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board_init (struct board *board)
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{
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memset (board, 0, sizeof board->elements);
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board->complexity = 9;
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for (unsigned i = 0; i < 9; ++i)
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{
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meta_init (&board->meta_quad[i]);
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meta_init (&board->meta_row[i]);
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meta_init (&board->meta_col[i]);
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}
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}
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bool
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meta_has_value (const struct metadata *meta, element_value value)
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{
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return ((meta->marked >> value) & 1) == 1;
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}
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void
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meta_set_value (struct metadata *meta, element_value value)
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{
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meta->marked |= 1 << value;
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}
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void
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meta_clear_values (struct metadata *meta)
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{
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meta->marked = 0;
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}
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static inline void
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meta_mark (struct metadata *meta, element_value value, unsigned index)
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{
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meta_set_value (meta, value);
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unsigned char count = meta->unique[value].count;
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if (count == 0)
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{
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meta->unique[value].count = 1;
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meta->unique[value].index = index;
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}
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else
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{
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meta->unique[value].count = 2;
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}
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}
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void
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board_meta_quad_refresh (struct board *board, board_pos qx, board_pos qy)
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{
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struct metadata *meta = BOARD_QUAD (board, qx, qy);
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board_pos quad_base_x = qx * 3;
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board_pos quad_base_y = qy * 3;
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meta_clear_values (meta);
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for (board_pos off_y = 0; off_y < 3; ++off_y)
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for (board_pos off_x = 0; off_x < 3; ++off_x)
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{
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struct board_element *elem =
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BOARD_ELEM (board, quad_base_x + off_x, quad_base_y + off_y);
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if (elem->has_value)
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meta_mark (meta, elem->value, (off_y * 3) + off_x);
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}
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}
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void
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board_meta_row_refresh (struct board *board, board_pos y)
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{
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struct metadata *meta = BOARD_ROW (board, y);
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meta_clear_values (meta);
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for (board_pos x = 0; x < 9; ++x)
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{
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struct board_element *elem = BOARD_ELEM (board, x, y);
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if (elem->has_value)
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meta_mark (meta, elem->value, x);
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}
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}
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void
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board_meta_col_refresh (struct board *board, board_pos x)
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{
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struct metadata *meta = BOARD_COL (board, x);
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meta_clear_values (meta);
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for (board_pos y = 0; y < 9; ++y)
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{
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struct board_element *elem = BOARD_ELEM (board, x, y);
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if (elem->has_value)
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meta_mark (meta, elem->value, y);
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}
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}
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bool
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board_meta_can_set (
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const struct board *board,
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board_pos x,
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board_pos y,
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element_value value
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)
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{
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if (is_in_bounds (x, y) && is_valid_value (value))
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{
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return ! (
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meta_has_value (BOARD_ROW (board, y), value) ||
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meta_has_value (BOARD_COL (board, x), value) ||
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meta_has_value (BOARD_QUAD (board, TO_QUAD (x), TO_QUAD (y)), value)
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);
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}
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else ERROR("Invalid parameters to function board_meta_can_set()");
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}
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@ -69,6 +211,11 @@ board_set (
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{
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if (is_in_bounds (x, y) && is_valid_value (value))
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{
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ASSERT (
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board_meta_can_set (board, x, y, value),
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"Attempt to set impossible value on board"
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);
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struct board_element *elem = BOARD_ELEM (board, x, y);
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elem->has_value = true;
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elem->value = value;
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@ -87,6 +234,11 @@ board_mark (
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{
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if (is_in_bounds (x, y) && is_valid_value (value))
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{
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ASSERT (
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! board_has_value (board, x, y),
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"Attempt to mark element with value"
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);
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struct board_element *elem = BOARD_ELEM (board, x, y);
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if (! board_is_marked (board, x, y, value))
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{
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@ -108,15 +260,18 @@ board_unmark (
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{
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if (is_in_bounds (x, y) && is_valid_value (value))
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{
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ASSERT (
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! board_has_value (board, x, y),
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"Attempt to mark element with value"
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);
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struct board_element *elem = BOARD_ELEM (board, x, y);
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if (board_is_marked (board, x, y, value))
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{
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/* Shift bit to correct place and then invert first 9 bits */
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elem->potential &= (1 << value) ^ 0x1FF;
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elem->potential ^= (1 << value);
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--(elem->complexity);
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if (elem->complexity < board->complexity)
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board->complexity = elem->complexity;
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}
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}
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else ERROR("Invalid parameters to function board_unmark()");
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@ -169,47 +324,6 @@ board_is_marked (
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}
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bool
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board_can_place_value (
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const struct board *board,
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board_pos x,
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board_pos y,
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element_value value
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)
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{
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if (is_in_bounds (x, y) && is_valid_value (value))
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{
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/* Check for x-axis */
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for (board_pos compare_x = 0; compare_x < 9; ++compare_x)
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{
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if (compare_x == x)
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continue;
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else if (
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board_has_value (board, compare_x, y) &&
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board_get_value (board, compare_x, y) == value
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)
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return false;
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}
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/* Check for y-axis */
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for (board_pos compare_y = 0; compare_y < 9; ++compare_y)
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{
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if (compare_y == y)
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continue;
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else if (
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board_has_value (board, x, compare_y) &&
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board_get_value (board, x, compare_y) == value
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)
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return false;
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}
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/* No matches */
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return true;
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}
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else ERROR("Invalid parameters to function board_can_place_value()");
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}
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bool
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board_is_valid (struct board *board)
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{
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@ -217,7 +331,7 @@ board_is_valid (struct board *board)
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for (board_pos x = 0; x < 9; ++x)
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if (
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board_has_value (board, x, y) &&
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! board_can_place_value (
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! board_meta_can_set (
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board,
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x,
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y,
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@ -245,14 +359,18 @@ board_update_marks (
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elem->complexity = 0;
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/* Check x-axis */
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for (board_pos check_x = 0; check_x < 9; ++check_x)
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if (check_x != x && board_has_value (board, check_x, y))
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elem->potential |= (1 << BOARD_ELEM (board, check_x, y)->value);
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elem->potential |= BOARD_QUAD (board, TO_QUAD (x), TO_QUAD (y))->marked;
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elem->potential |= BOARD_ROW (board, y)->marked;
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elem->potential |= BOARD_COL (board, x)->marked;
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/* Check y-axis */
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for (board_pos check_y = 0; check_y < 9; ++check_y)
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if (check_y != y && board_has_value (board, x, check_y))
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elem->potential |= (1 << BOARD_ELEM (board, x, check_y)->value);
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// for (board_pos check_x = 0; check_x < 9; ++check_x)
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// if (check_x != x && board_has_value (board, check_x, y))
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// elem->potential |= (1 << BOARD_ELEM (board, check_x, y)->value);
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// /* Check y-axis */
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// for (board_pos check_y = 0; check_y < 9; ++check_y)
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// if (check_y != y && board_has_value (board, x, check_y))
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// elem->potential |= (1 << BOARD_ELEM (board, x, check_y)->value);
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/* Invert matches */
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elem->potential ^= 0x1FF;
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@ -265,10 +383,6 @@ board_update_marks (
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++(elem->complexity);
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potential >>= 1;
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}
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/* Store complexity if element is the simplest */
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if (elem->complexity < board->complexity)
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board->complexity = elem->complexity;
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}
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else ERROR("Invalid parameters to function board_update_marks()");
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}
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@ -463,7 +577,6 @@ board_update_marks_by_quad (
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changed |= true;
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result.unique->potential = 1 << value;
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result.unique->complexity = 1;
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board->complexity = 1;
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}
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}
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return changed;
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@ -583,10 +696,7 @@ board_update_marks_by_rows (struct board *board)
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{
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struct board_element *elem = BOARD_ELEM (board, x ,y);
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elem->complexity = 1;
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board->complexity = 1;
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changed |= elem->potential != (elem->potential = (1 << value));
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abort();
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}
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}
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@ -618,7 +728,6 @@ board_update_marks_by_cols (struct board *board)
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{
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struct board_element *elem = BOARD_ELEM (board, x ,y);
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elem->complexity = 1;
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board->complexity = 1;
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changed |= elem->potential != (elem->potential = (1 << value));
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}
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}
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@ -639,21 +748,22 @@ board_update_all_marks (struct board *board)
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if (! board_has_value (board, x, y))
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board_update_marks (board, x, y);
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return;
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bool changed;
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do
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{
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changed = false;
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/* Update marks by exclusion analysis */
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// for (board_pos y = 0; y < 9; ++y)
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// for (board_pos x = 0; x < 9; ++x)
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// if (! board_has_value (board, x, y))
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// changed |= board_update_marks_by_excl (board, x, y);
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for (board_pos y = 0; y < 9; ++y)
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for (board_pos x = 0; x < 9; ++x)
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if (! board_has_value (board, x, y))
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changed |= board_update_marks_by_excl (board, x, y);
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// /* Update marks by quad potential analysis */
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// for (board_pos y = 0; y < 9; y += 3)
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// for (board_pos x = 0; x < 9; x += 3)
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// changed |= board_update_marks_by_quad (board, x, y);
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/* Update marks by quad potential analysis */
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for (board_pos y = 0; y < 9; y += 3)
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for (board_pos x = 0; x < 9; x += 3)
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changed |= board_update_marks_by_quad (board, x, y);
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changed |= board_update_marks_by_rows (board);
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changed |= board_update_marks_by_cols (board);
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@ -672,7 +782,7 @@ board_place (
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{
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if (is_in_bounds (x, y) && is_valid_value (value))
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{
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if (board_can_place_value (board, x, y, value))
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if (board_meta_can_set (board, x, y, value))
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{
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/* Unmark x-axis */
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for (board_pos unmark_x = 0; unmark_x < 9; ++unmark_x)
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@ -702,7 +812,12 @@ board_place (
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board_unmark (board, target_x, target_y, value);
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}
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/* Set value */
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/* Update metadata */
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meta_set_value (BOARD_QUAD (board, quad_x, quad_y), value);
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meta_set_value (BOARD_ROW (board, y), value);
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meta_set_value (BOARD_COL (board, x), value);
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/* Set value */
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board_set (board, x, y, value);
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/* Update board complexity */
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@ -726,7 +841,7 @@ board_place_speculative (
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if (is_in_bounds (x, y) && is_valid_value (value))
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{
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/* Ensure value can be placed*/
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if (board_can_place_value (board, x, y, value))
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if (board_meta_can_set (board, x, y, value))
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{
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/* Create duplicate and place value */
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board_copy (board, board_duplicate);
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115
board.h
115
board.h
@ -11,6 +11,22 @@
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*/
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#define BOARD_ELEM(board_ptr, x, y) (&(board_ptr)->elements[((y) * 9) + (x)])
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/**
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* Get a `struct metadata`-entry from a specified location on the quadrand grid
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*/
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#define BOARD_QUAD(board_ptr, qx, qy) (&(board_ptr)->meta_quad[(qy) * 3 + (qx)])
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/**
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* Get a `struct metadata`-entry from a specified row value
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*/
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#define BOARD_ROW(board_ptr, y) (&(board_ptr)->meta_row[(y)])
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/**
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* Get a `struct metadata`-entry from a specified column value
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*/
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#define BOARD_COL(board_ptr, x) (&(board_ptr)->meta_col[(x)])
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/**
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* Convert any valid board position to a quadrant base position (lowest index)
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*/
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@ -38,24 +54,104 @@ struct board_element {
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};
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};
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/**
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* Board region metadata
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*/
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struct metadata {
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unsigned short marked : 9; /* Which values have been marked */
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struct { /* Unique potentials */
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unsigned char count : 2; /* Whether or not a potential is unique */
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unsigned char index : 3; /* Metadata index. Context-specific */
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} unique[9];
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};
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/**
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* Board structure representing the state of a Sudoku game
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* Complexity describes
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* Complexity describes how many possible values an element can legally have
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*
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* TODO: Replace elements with packed structure
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*/
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struct board {
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/* Immediate data*/
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struct board_element elements[81]; /* Game board */
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unsigned char complexity; /* Complexity of simplest element */
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unsigned char complexity : 3; /* Complexity of simplest element */
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/* Metadata */
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struct metadata meta_quad [9]; /* Quadrant metadata */
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struct metadata meta_row [9]; /* Row metadata */
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struct metadata meta_col [9]; /* Column metadata */
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};
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/**
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* Initialize a board to a blank state with 0 complexity
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* Initialize metadata to a blank state
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*/
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void
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meta_init (struct metadata *meta);
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/**
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* Initialize a board to a blank state with maximum complexity
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*/
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void
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board_init (struct board *board);
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/**
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* Check if a metadata structure has marked a given value
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*/
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bool
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meta_has_value (const struct metadata *meta, element_value value);
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/**
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* Set value as marked for the given metadata structure
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*/
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void
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meta_set_value (struct metadata *meta, element_value value);
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/**
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* Clear all marked values for the given metadata structure
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*/
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void
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meta_clear_values (struct metadata *meta);
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/**
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* Refresh metadata for a given quadrant
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*/
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void
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board_meta_quad_refresh (struct board *board, board_pos qx, board_pos qy);
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/**
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* Refresh metadata for a given row
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*/
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void
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board_meta_row_refresh (struct board *board, board_pos y);
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/**
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* Refresh metadata for a given column
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*/
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void
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board_meta_col_refresh (struct board *board, board_pos x);
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/**
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* Check if a value can be set at a given position on the board based on
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* analysing the metadata structures of `board`
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*/
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bool
|
||||
board_meta_can_set (
|
||||
const struct board *board,
|
||||
board_pos x,
|
||||
board_pos y,
|
||||
element_value value
|
||||
);
|
||||
|
||||
|
||||
/**
|
||||
* Set the value of an element on the board
|
||||
*
|
||||
@ -135,19 +231,6 @@ board_is_marked (
|
||||
);
|
||||
|
||||
|
||||
/**
|
||||
* Checks if placing the given value at the given position on the board would
|
||||
* leave the board in a valid state
|
||||
*/
|
||||
bool
|
||||
board_can_place_value (
|
||||
const struct board *board,
|
||||
board_pos x,
|
||||
board_pos y,
|
||||
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
|
||||
|
||||
17
main.c
17
main.c
@ -292,9 +292,14 @@ simplify (
|
||||
struct board *board = board_specs->board_specs[depth];
|
||||
|
||||
bool error;
|
||||
|
||||
bool placed = false;
|
||||
unsigned count = 0;
|
||||
|
||||
/* Reduce using low-complexity computation */
|
||||
while (board->complexity == 1)
|
||||
{
|
||||
placed = false;
|
||||
for (board_pos y = 0; y < 9; ++y)
|
||||
for (board_pos x = 0; x < 9; ++x)
|
||||
if (! board_has_value (board, x, y))
|
||||
@ -305,9 +310,19 @@ simplify (
|
||||
element_value value = first_potential_value (elem, board, &error);
|
||||
if (error) return false;
|
||||
|
||||
board_place (board, x, y, value);
|
||||
placed = true;
|
||||
++count;
|
||||
|
||||
if (! board_place (board, x, y, value))
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (! placed)
|
||||
{
|
||||
print_board (board_specs->board_specs[depth], board_specs->board_specs[0], 21, 0);
|
||||
printf ("Count: %u\n", count);
|
||||
abort ();
|
||||
}
|
||||
}
|
||||
|
||||
/* Attempt to reduce with speculative placement */
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user