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Implement board solver using board reuse

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This commit is contained in:
Gabriel Tofvesson 2020-02-25 19:32:45 +01:00
parent 0e4506cd52
commit 10ad1cdf67
1 changed files with 74 additions and 22 deletions
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96
main.c
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@ -7,10 +7,54 @@
#include <unistd.h>
#include "board.h"
/**
* How many boards to allocate by default for board spec
* Average depth for highly complex boards is between 10 and 12
*/
#define DEFAULT_DEPTH 10
/**
* How many boards to allocate per depth increase
* Higher values mean fewer reallocations, by with greater resource costs
*/
#define DEPTH_INCREMENT 3
struct boards_table {
struct board **board_specs;
unsigned long long max_depth;
};
void
tables_ensure_depth (struct boards_table *board_spec, unsigned long long depth)
{
if (board_spec->max_depth <= depth)
{
/* Compute new max depth */
unsigned long long new_max;
if (board_spec->max_depth == 0)
new_max = DEFAULT_DEPTH;
else
new_max = board_spec->max_depth + DEPTH_INCREMENT;
/* Disregard NULL return value. What's it gonna do, segfault? :P */
board_spec->board_specs = realloc (
board_spec->board_specs,
sizeof (struct board *) * new_max
);
/* Allocate boards */
for (unsigned long long l = board_spec->max_depth; l < new_max; ++l)
board_spec->board_specs[l] = malloc (sizeof (struct board));
/* Update max depth */
board_spec->max_depth = new_max;
}
}
bool
simplify (struct board *board, unsigned long long depth);
simplify (struct boards_table *board_spec, unsigned long long depth);
struct board_file
@ -176,8 +220,11 @@ first_potential_value (struct board_element *element, struct board *board, bool
* Reduce away all elements on board with complexity=1 until none remain
*/
bool
simplify (struct board *board, unsigned long long depth)
simplify (struct boards_table *board_specs, unsigned long long depth)
{
/* Get current table */
struct board *board = board_specs->board_specs[depth];
bool error;
/* Reduce using low-complexity computation */
while (board->complexity == 1)
@ -212,31 +259,30 @@ simplify (struct board *board, unsigned long long depth)
for (element_value value = 0; value < 9; ++value)
{
/* Try speculative placement of each potential value and recurse */
tables_ensure_depth (board_specs, depth + 1);
if ((elem->potential & (1 << value)) != 0)
{
/* printf ("Speculating (%u, %u) = %u (depth = %llu)\n", x, y, value, depth); */
struct board *board_spec =
board_place_speculative (board, x, y, value);
board_place_speculative (
board,
board_specs->board_specs[depth + 1],
x,
y,
value
);
/* If speculative placement failed, try another value */
if (board_spec == NULL)
{
/* printf ("Speculation failed catastrophically\n"); */
continue;
}
/* Found solution */
if (simplify (board_spec, depth + 1) && board_spec->complexity == 0)
if (simplify (board_specs, depth + 1) && board_spec->complexity == 0)
{
board_copy (board_spec, board);
x = 9;
y = 9;
value = 9;
}
/* else printf ("Speculation failed\n"); */
/* board_copy leaves resposibility of freeing to caller */
free (board_spec);
}
}
}
@ -254,27 +300,33 @@ main (int argc, char **argv, char **env)
if (file.fd == -1 || file.data == NULL)
return -1;
struct board board;
copy_to_board (file, &board);
/* Allocate board */
struct boards_table boards;
boards.max_depth = 0;
tables_ensure_depth (&boards, 0);
struct board *root_board = boards.board_specs[0];
copy_to_board (file, root_board);
close_board_file (file);
board_update_all_marks (&board);
board_update_all_marks (root_board);
print_board (&board);
print_board (root_board);
if (board_is_valid (&board))
printf ("Board is valid!\nBoard complexity: %u\n", board.complexity);
if (board_is_valid (root_board))
printf ("Board is valid!\nBoard complexity: %u\n", root_board->complexity);
else
puts ("Board is invalid!");
puts("\nReducing...");
simplify (&board, 1);
simplify (&boards, 0);
print_board (&board);
print_board (root_board);
if (board_is_valid (&board))
printf ("Board is valid!\nBoard complexity: %u\n", board.complexity);
if (board_is_valid (root_board))
printf ("Board is valid!\nBoard complexity: %u\n", root_board->complexity);
else
puts ("Board is invalid!");