GabrielTofvesson/sudoku
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Implement board and element complexity

Browse Source
This commit is contained in:
Gabriel Tofvesson 2020-02-28 01:08:48 +01:00
parent ac5de85171
commit 6e79c9b366
2 changed files with 39 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
board.c
View File

@ -47,7 +47,7 @@ void
board_init (struct board *board)
{
memset (board, 0, sizeof board->elements);
board->complexity = 0;
board->complexity = 9;
}
@ -80,7 +80,11 @@ board_mark (
if (is_in_bounds (x, y) && is_valid_value (value))
{
struct board_element *elem = BOARD_ELEM (board, x, y);
elem->potential |= 1 << value;
if (! board_is_marked (board, x, y, value))
{
elem->potential |= 1 << value;
++(elem->complexity);
}
}
else ERROR("Invalid parameters to function board_mark()");
}
@ -98,8 +102,14 @@ board_unmark (
{
struct board_element *elem = BOARD_ELEM (board, x, y);
/* Shift bit to correct place and then invert first 9 bits */
elem->potential &= (1 << value) ^ 0x1FF;
if (board_is_marked (board, x, y, value))
{
/* Shift bit to correct place and then invert first 9 bits */
elem->potential &= (1 << value) ^ 0x1FF;
--(elem->complexity);
if (elem->complexity < board->complexity)
board->complexity = elem->complexity;
}
}
else ERROR("Invalid parameters to function board_unmark()");
}
@ -224,19 +234,33 @@ board_update_marks (
/* Mark all values as impossible */
elem->potential = 0;
elem->complexity = 0;
/* Check x-axis */
for (board_pos check_x = 0; check_x < 9; ++check_x)
if (check_x != x && board_has_value (board, check_x, y))
elem->potential |= 1 << BOARD_ELEM (board, check_x, y)->value;
elem->potential |= (1 << BOARD_ELEM (board, check_x, y)->value);
/* Check y-axis */
for (board_pos check_y = 0; check_y < 9; ++check_y)
if (check_y != y && board_has_value (board, x, check_y))
elem->potential |= 1 << BOARD_ELEM (board, x, check_y)->value;
elem->potential |= (1 << BOARD_ELEM (board, x, check_y)->value);
/* Invert matches */
elem->potential ^= 0x1FF;
/* Count marked bits */
unsigned char potential = elem->potential;
while (potential != 0)
{
if (potential & 1 == 1)
++(elem->complexity);
potential >>= 1;
}
/* Store complexity if element is the simplest */
if (elem->complexity < board->complexity)
board->complexity = elem->complexity;
}
else ERROR("Invalid parameters to function board_update_marks()");
}

11
board.h
View File

@ -16,13 +16,20 @@ typedef unsigned char element_value;
/**
* Simple definition of a board element. Vaild values range: 0-8
* Complexity describes how many possible values would be valid for an instance
* of a board element. For example, if it could be either 1 or 5, it would have
* a complexity of 2. If it could hold 4, 5 or 8, it would have a complexity
* of 3
*/
struct board_element {
bool has_value : 1; /* Whether element has a decided value */
union {
element_value value : 4; /* Value of element */
unsigned short potential : 9; /* Bitfield of possible values */
element_value value : 4; /* Value of element */
struct {
unsigned short potential : 9; /* Bitfield of possible values */
unsigned char complexity : 4; /* Complexity tracker */
};
};
};