solver.c File Reference

8-direction crossword word-search solver. More...

#include "solver.h"
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

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Macros
#define	N_DIRS   8

Functions
CharGrid *	grid_create (int rows, int cols)
	Allocate a CharGrid of the given dimensions, filled with spaces.
void	grid_fill (CharGrid *grid, const int *labels, size_t count)
	Fill a CharGrid from an array of predicted character indices.
CharGrid *	grid_load (const char *path)
	Read a CharGrid from a plain-text file.
void	grid_print (const CharGrid *g)
	Print a CharGrid to stdout (for debugging / verbose mode).
void	grid_free (CharGrid *g)
	Free a CharGrid.
static int	try_direction (const CharGrid *grid, const char *word, int r, int c, int dir)
	Check whether word fits in grid starting at (r, c) going in direction dir.
WordResult	solver_find (const CharGrid *grid, const char *word)
	Search for word in grid in all 8 directions.
const char *	solver_dir_name (int dir)
	Return the human-readable name of direction index dir.

Variables
static const int	DIR_DR [N_DIRS] = { 0, 1, 1, 1, 0, -1, -1, -1}
	Row and column deltas for each of the 8 search directions.
static const int	DIR_DC [N_DIRS] = { 1, 1, 0, -1, -1, -1, 0, 1}
static const char *	DIR_NAMES [N_DIRS]

Detailed Description

8-direction crossword word-search solver.

Macro Definition Documentation

N_DIRS

#define N_DIRS   8

Number of search directions.

Function Documentation

grid_create()

CharGrid * grid_create	(	int	rows,
		int	cols )

Allocate a CharGrid of the given dimensions, filled with spaces.

Parameters

rows	Number of rows.
cols	Number of columns.

Returns

Heap-allocated CharGrid, or NULL on failure. Free with grid_free().

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grid_fill()

void grid_fill	(	CharGrid *	grid,
		const int *	labels,
		size_t	count )

Fill a CharGrid from an array of predicted character indices.

Parameters

grid	Target grid (must already be allocated with the right size).
labels	Array of class indices in [0, 25]; labels[r*cols + c] gives the index for cell (r, c). 0='A', 25='Z'.
count	Number of elements in labels (must equal rows * cols).

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grid_free()

void grid_free

(

CharGrid *

grid

)

Free a CharGrid.

Parameters

grid	Grid to free. No-op if NULL.

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grid_load()

CharGrid * grid_load

(

const char *

path

)

Read a CharGrid from a plain-text file.

File format (first line: dimensions, then one row per line):

rows cols
ABCDE
FGHIJ
…

Parameters

path	Path to the grid file.

Returns

Heap-allocated CharGrid on success, NULL on error. Free with grid_free().

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grid_print()

void grid_print

(

const CharGrid *

grid

)

Print a CharGrid to stdout (for debugging / verbose mode).

Parameters

grid	Grid to display.

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solver_dir_name()

const char * solver_dir_name

(

int

dir

)

Return the human-readable name of direction index dir.

Directions are numbered 0–7: 0=RIGHT, 1=DOWN_RIGHT, 2=DOWN, 3=DOWN_LEFT, 4=LEFT, 5=UP_LEFT, 6=UP, 7=UP_RIGHT

Parameters

dir	Direction index in [0, 7].

Returns

Constant string (e.g. "RIGHT"), or "UNKNOWN" if out of range.

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solver_find()

WordResult solver_find	(	const CharGrid *	grid,
		const char *	word )

Search for word in grid in all 8 directions.

The search is case-insensitive; the grid and word are both converted to uppercase before comparison.

Parameters

grid	Character grid to search in.
word	Null-terminated string to search for (A–Z, case-insensitive).

Returns

WordResult with found=1 and coordinates if found, or found=0 if not present.

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try_direction()

int try_direction ( const CharGrid * grid, const char * word, int r, int c, int dir )

static

Check whether word fits in grid starting at (r, c) going in direction dir.

Parameters

grid	Character grid.
word	Uppercase null-terminated search string.
r	Starting row.
c	Starting column.
dir	Direction index (0–7).

Returns

1 if the word matches in that direction, 0 otherwise.

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Variable Documentation

DIR_DC

const int DIR_DC[N_DIRS] = { 1, 1, 0, -1, -1, -1, 0, 1}

static

DIR_DR

const int DIR_DR[N_DIRS] = { 0, 1, 1, 1, 0, -1, -1, -1}

static

Row and column deltas for each of the 8 search directions.

Indexed 0–7: 0 = RIGHT (dr= 0, dc=+1) 1 = DOWN_RIGHT (dr=+1, dc=+1) 2 = DOWN (dr=+1, dc= 0) 3 = DOWN_LEFT (dr=+1, dc=-1) 4 = LEFT (dr= 0, dc=-1) 5 = UP_LEFT (dr=-1, dc=-1) 6 = UP (dr=-1, dc= 0) 7 = UP_RIGHT (dr=-1, dc=+1)

DIR_NAMES

const char* DIR_NAMES[N_DIRS]

static

Initial value:

                            = {
    "RIGHT", "DOWN_RIGHT", "DOWN", "DOWN_LEFT",
    "LEFT",  "UP_LEFT",    "UP",   "UP_RIGHT"
}