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Implement board and element complexity

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Gabriel Tofvesson 2020-02-28 01:08:48 +01:00
parent ac5de85171
commit 6e79c9b366
2 changed files with 39 additions and 8 deletions
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36
board.c
View File

@ -47,7 +47,7 @@ void
board_init (struct board *board) board_init (struct board *board)
{ {
memset (board, 0, sizeof board->elements); 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)) if (is_in_bounds (x, y) && is_valid_value (value))
{ {
struct board_element *elem = BOARD_ELEM (board, x, y); 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()"); else ERROR("Invalid parameters to function board_mark()");
} }
@ -98,8 +102,14 @@ board_unmark (
{ {
struct board_element *elem = BOARD_ELEM (board, x, y); struct board_element *elem = BOARD_ELEM (board, x, y);
/* Shift bit to correct place and then invert first 9 bits */ if (board_is_marked (board, x, y, value))
elem->potential &= (1 << value) ^ 0x1FF; {
/* 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()"); else ERROR("Invalid parameters to function board_unmark()");
} }
@ -224,19 +234,33 @@ board_update_marks (
/* Mark all values as impossible */ /* Mark all values as impossible */
elem->potential = 0; elem->potential = 0;
elem->complexity = 0;
/* Check x-axis */ /* Check x-axis */
for (board_pos check_x = 0; check_x < 9; ++check_x) for (board_pos check_x = 0; check_x < 9; ++check_x)
if (check_x != x && board_has_value (board, check_x, y)) 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 */ /* Check y-axis */
for (board_pos check_y = 0; check_y < 9; ++check_y) for (board_pos check_y = 0; check_y < 9; ++check_y)
if (check_y != y && board_has_value (board, x, 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 */ /* Invert matches */
elem->potential ^= 0x1FF; 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()"); 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 * 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 { struct board_element {
bool has_value : 1; /* Whether element has a decided value */ bool has_value : 1; /* Whether element has a decided value */
union { union {
element_value value : 4; /* Value of element */ element_value value : 4; /* Value of element */
unsigned short potential : 9; /* Bitfield of possible values */ struct {
unsigned short potential : 9; /* Bitfield of possible values */
unsigned char complexity : 4; /* Complexity tracker */
};
}; };
}; };