ref: 8d81c1814d249d3aa2342c02363a0220c54bf71c
dir: /lightup.c/
/*
* lightup.c: Implementation of the Nikoli game 'Light Up'.
*
* Possible future solver enhancements:
*
* - In a situation where two clues are diagonally adjacent, you can
* deduce bounds on the number of lights shared between them. For
* instance, suppose a 3 clue is diagonally adjacent to a 1 clue:
* of the two squares adjacent to both clues, at least one must be
* a light (or the 3 would be unsatisfiable) and yet at most one
* must be a light (or the 1 would be overcommitted), so in fact
* _exactly_ one must be a light, and hence the other two squares
* adjacent to the 3 must also be lights and the other two adjacent
* to the 1 must not. Likewise if the 3 is replaced with a 2 but
* one of its other two squares is known not to be a light, and so
* on.
*
* - In a situation where two clues are orthogonally separated (not
* necessarily directly adjacent), you may be able to deduce
* something about the squares that align with each other. For
* instance, suppose two clues are vertically adjacent. Consider
* the pair of squares A,B horizontally adjacent to the top clue,
* and the pair C,D horizontally adjacent to the bottom clue.
* Assuming no intervening obstacles, A and C align with each other
* and hence at most one of them can be a light, and B and D
* likewise, so we must have at most two lights between the four
* squares. So if the clues indicate that there are at _least_ two
* lights in those four squares because the top clue requires at
* least one of AB to be a light and the bottom one requires at
* least one of CD, then we can in fact deduce that there are
* _exactly_ two lights between the four squares, and fill in the
* other squares adjacent to each clue accordingly. For instance,
* if both clues are 3s, then we instantly deduce that all four of
* the squares _vertically_ adjacent to the two clues must be
* lights. (For that to happen, of course, there'd also have to be
* a black square in between the clues, so the two inner lights
* don't light each other.)
*
* - I haven't thought it through carefully, but there's always the
* possibility that both of the above deductions are special cases
* of some more general pattern which can be made computationally
* feasible...
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <math.h>
#include "puzzles.h"
/*
* In standalone solver mode, `verbose' is a variable which can be
* set by command-line option; in debugging mode it's simply always
* true.
*/
#if defined STANDALONE_SOLVER
#define SOLVER_DIAGNOSTICS
int verbose = 0;
#undef debug
#define debug(x) printf x
#elif defined SOLVER_DIAGNOSTICS
#define verbose 2
#endif
/* --- Constants, structure definitions, etc. --- */
#define PREFERRED_TILE_SIZE 32
#define TILE_SIZE (ds->tilesize)
#define BORDER (TILE_SIZE / 2)
#define TILE_RADIUS (ds->crad)
#define COORD(x) ( (x) * TILE_SIZE + BORDER )
#define FROMCOORD(x) ( ((x) - BORDER + TILE_SIZE) / TILE_SIZE - 1 )
#define FLASH_TIME 0.30F
enum {
COL_BACKGROUND,
COL_GRID,
COL_BLACK, /* black */
COL_LIGHT, /* white */
COL_LIT, /* yellow */
COL_ERROR, /* red */
COL_CURSOR,
NCOLOURS
};
enum { SYMM_NONE, SYMM_REF2, SYMM_ROT2, SYMM_REF4, SYMM_ROT4, SYMM_MAX };
#define DIFFCOUNT 2
struct game_params {
int w, h;
int blackpc; /* %age of black squares */
int symm;
int difficulty; /* 0 to DIFFCOUNT */
};
#define F_BLACK 1
/* flags for black squares */
#define F_NUMBERED 2 /* it has a number attached */
#define F_NUMBERUSED 4 /* this number was useful for solving */
/* flags for non-black squares */
#define F_IMPOSSIBLE 8 /* can't put a light here */
#define F_LIGHT 16
#define F_MARK 32
struct game_state {
int w, h, nlights;
int *lights; /* For black squares, (optionally) the number
of surrounding lights. For non-black squares,
the number of times it's lit. size h*w*/
unsigned int *flags; /* size h*w */
bool completed, used_solve;
};
#define GRID(gs,grid,x,y) (gs->grid[(y)*((gs)->w) + (x)])
/* A ll_data holds information about which lights would be lit by
* a particular grid location's light (or conversely, which locations
* could light a specific other location). */
/* most things should consider this struct opaque. */
typedef struct {
int ox,oy;
int minx, maxx, miny, maxy;
bool include_origin;
} ll_data;
/* Macro that executes 'block' once per light in lld, including
* the origin if include_origin is specified. 'block' can use
* lx and ly as the coords. */
#define FOREACHLIT(lld,block) do { \
int lx,ly; \
ly = (lld)->oy; \
for (lx = (lld)->minx; lx <= (lld)->maxx; lx++) { \
if (lx == (lld)->ox) continue; \
block \
} \
lx = (lld)->ox; \
for (ly = (lld)->miny; ly <= (lld)->maxy; ly++) { \
if (!(lld)->include_origin && ly == (lld)->oy) continue; \
block \
} \
} while(0)
typedef struct {
struct { int x, y; unsigned int f; } points[4];
int npoints;
} surrounds;
/* Fills in (doesn't allocate) a surrounds structure with the grid locations
* around a given square, taking account of the edges. */
static void get_surrounds(const game_state *state, int ox, int oy,
surrounds *s)
{
assert(ox >= 0 && ox < state->w && oy >= 0 && oy < state->h);
s->npoints = 0;
#define ADDPOINT(cond,nx,ny) do {\
if (cond) { \
s->points[s->npoints].x = (nx); \
s->points[s->npoints].y = (ny); \
s->points[s->npoints].f = 0; \
s->npoints++; \
} } while(0)
ADDPOINT(ox > 0, ox-1, oy);
ADDPOINT(ox < (state->w-1), ox+1, oy);
ADDPOINT(oy > 0, ox, oy-1);
ADDPOINT(oy < (state->h-1), ox, oy+1);
}
/* --- Game parameter functions --- */
#define DEFAULT_PRESET 0
static const struct game_params lightup_presets[] = {
{ 7, 7, 20, SYMM_ROT4, 0 },
{ 7, 7, 20, SYMM_ROT4, 1 },
{ 7, 7, 20, SYMM_ROT4, 2 },
{ 10, 10, 20, SYMM_ROT2, 0 },
{ 10, 10, 20, SYMM_ROT2, 1 },
#ifdef SLOW_SYSTEM
{ 12, 12, 20, SYMM_ROT2, 0 },
{ 12, 12, 20, SYMM_ROT2, 1 },
#else
{ 10, 10, 20, SYMM_ROT2, 2 },
{ 14, 14, 20, SYMM_ROT2, 0 },
{ 14, 14, 20, SYMM_ROT2, 1 },
{ 14, 14, 20, SYMM_ROT2, 2 }
#endif
};
static game_params *default_params(void)
{
game_params *ret = snew(game_params);
*ret = lightup_presets[DEFAULT_PRESET];
return ret;
}
static bool game_fetch_preset(int i, char **name, game_params **params)
{
game_params *ret;
char buf[80];
if (i < 0 || i >= lenof(lightup_presets))
return false;
ret = default_params();
*ret = lightup_presets[i];
*params = ret;
sprintf(buf, "%dx%d %s",
ret->w, ret->h,
ret->difficulty == 2 ? "hard" :
ret->difficulty == 1 ? "tricky" : "easy");
*name = dupstr(buf);
return true;
}
static void free_params(game_params *params)
{
sfree(params);
}
static game_params *dup_params(const game_params *params)
{
game_params *ret = snew(game_params);
*ret = *params; /* structure copy */
return ret;
}
#define EATNUM(x) do { \
(x) = atoi(string); \
while (*string && isdigit((unsigned char)*string)) string++; \
} while(0)
static void decode_params(game_params *params, char const *string)
{
EATNUM(params->w);
if (*string == 'x') {
string++;
EATNUM(params->h);
}
if (*string == 'b') {
string++;
EATNUM(params->blackpc);
}
if (*string == 's') {
string++;
EATNUM(params->symm);
} else {
/* cope with user input such as '18x10' by ensuring symmetry
* is not selected by default to be incompatible with dimensions */
if (params->symm == SYMM_ROT4 && params->w != params->h)
params->symm = SYMM_ROT2;
}
params->difficulty = 0;
/* cope with old params */
if (*string == 'r') {
params->difficulty = 2;
string++;
}
if (*string == 'd') {
string++;
EATNUM(params->difficulty);
}
}
static char *encode_params(const game_params *params, bool full)
{
char buf[80];
if (full) {
sprintf(buf, "%dx%db%ds%dd%d",
params->w, params->h, params->blackpc,
params->symm,
params->difficulty);
} else {
sprintf(buf, "%dx%d", params->w, params->h);
}
return dupstr(buf);
}
static config_item *game_configure(const game_params *params)
{
config_item *ret;
char buf[80];
ret = snewn(6, config_item);
ret[0].name = "Width";
ret[0].type = C_STRING;
sprintf(buf, "%d", params->w);
ret[0].u.string.sval = dupstr(buf);
ret[1].name = "Height";
ret[1].type = C_STRING;
sprintf(buf, "%d", params->h);
ret[1].u.string.sval = dupstr(buf);
ret[2].name = "%age of black squares";
ret[2].type = C_STRING;
sprintf(buf, "%d", params->blackpc);
ret[2].u.string.sval = dupstr(buf);
ret[3].name = "Symmetry";
ret[3].type = C_CHOICES;
ret[3].u.choices.choicenames = ":None"
":2-way mirror:2-way rotational"
":4-way mirror:4-way rotational";
ret[3].u.choices.selected = params->symm;
ret[4].name = "Difficulty";
ret[4].type = C_CHOICES;
ret[4].u.choices.choicenames = ":Easy:Tricky:Hard";
ret[4].u.choices.selected = params->difficulty;
ret[5].name = NULL;
ret[5].type = C_END;
return ret;
}
static game_params *custom_params(const config_item *cfg)
{
game_params *ret = snew(game_params);
ret->w = atoi(cfg[0].u.string.sval);
ret->h = atoi(cfg[1].u.string.sval);
ret->blackpc = atoi(cfg[2].u.string.sval);
ret->symm = cfg[3].u.choices.selected;
ret->difficulty = cfg[4].u.choices.selected;
return ret;
}
static const char *validate_params(const game_params *params, bool full)
{
if (params->w < 2 || params->h < 2)
return "Width and height must be at least 2";
if (full) {
if (params->blackpc < 5 || params->blackpc > 100)
return "Percentage of black squares must be between 5% and 100%";
if (params->w != params->h) {
if (params->symm == SYMM_ROT4)
return "4-fold symmetry is only available with square grids";
}
if (params->symm < 0 || params->symm >= SYMM_MAX)
return "Unknown symmetry type";
if (params->difficulty < 0 || params->difficulty > DIFFCOUNT)
return "Unknown difficulty level";
}
return NULL;
}
/* --- Game state construction/freeing helper functions --- */
static game_state *new_state(const game_params *params)
{
game_state *ret = snew(game_state);
ret->w = params->w;
ret->h = params->h;
ret->lights = snewn(ret->w * ret->h, int);
ret->nlights = 0;
memset(ret->lights, 0, ret->w * ret->h * sizeof(int));
ret->flags = snewn(ret->w * ret->h, unsigned int);
memset(ret->flags, 0, ret->w * ret->h * sizeof(unsigned int));
ret->completed = false;
ret->used_solve = false;
return ret;
}
static game_state *dup_game(const game_state *state)
{
game_state *ret = snew(game_state);
ret->w = state->w;
ret->h = state->h;
ret->lights = snewn(ret->w * ret->h, int);
memcpy(ret->lights, state->lights, ret->w * ret->h * sizeof(int));
ret->nlights = state->nlights;
ret->flags = snewn(ret->w * ret->h, unsigned int);
memcpy(ret->flags, state->flags, ret->w * ret->h * sizeof(unsigned int));
ret->completed = state->completed;
ret->used_solve = state->used_solve;
return ret;
}
static void free_game(game_state *state)
{
sfree(state->lights);
sfree(state->flags);
sfree(state);
}
static void debug_state(game_state *state)
{
int x, y;
char c = '?';
for (y = 0; y < state->h; y++) {
for (x = 0; x < state->w; x++) {
c = '.';
if (GRID(state, flags, x, y) & F_BLACK) {
if (GRID(state, flags, x, y) & F_NUMBERED)
c = GRID(state, lights, x, y) + '0';
else
c = '#';
} else {
if (GRID(state, flags, x, y) & F_LIGHT)
c = 'O';
else if (GRID(state, flags, x, y) & F_IMPOSSIBLE)
c = 'X';
}
debug(("%c", (int)c));
}
debug((" "));
for (x = 0; x < state->w; x++) {
if (GRID(state, flags, x, y) & F_BLACK)
c = '#';
else {
c = (GRID(state, flags, x, y) & F_LIGHT) ? 'A' : 'a';
c += GRID(state, lights, x, y);
}
debug(("%c", (int)c));
}
debug(("\n"));
}
}
/* --- Game completion test routines. --- */
/* These are split up because occasionally functions are only
* interested in one particular aspect. */
/* Returns true if all grid spaces are lit. */
static bool grid_lit(game_state *state)
{
int x, y;
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
if (GRID(state,flags,x,y) & F_BLACK) continue;
if (GRID(state,lights,x,y) == 0)
return false;
}
}
return true;
}
/* Returns non-zero if any lights are lit by other lights. */
static bool grid_overlap(game_state *state)
{
int x, y;
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
if (!(GRID(state, flags, x, y) & F_LIGHT)) continue;
if (GRID(state, lights, x, y) > 1)
return true;
}
}
return false;
}
static bool number_wrong(const game_state *state, int x, int y)
{
surrounds s;
int i, n, empty, lights = GRID(state, lights, x, y);
/*
* This function computes the display hint for a number: we
* turn the number red if it is definitely wrong. This means
* that either
*
* (a) it has too many lights around it, or
* (b) it would have too few lights around it even if all the
* plausible squares (not black, lit or F_IMPOSSIBLE) were
* filled with lights.
*/
assert(GRID(state, flags, x, y) & F_NUMBERED);
get_surrounds(state, x, y, &s);
empty = n = 0;
for (i = 0; i < s.npoints; i++) {
if (GRID(state,flags,s.points[i].x,s.points[i].y) & F_LIGHT) {
n++;
continue;
}
if (GRID(state,flags,s.points[i].x,s.points[i].y) & F_BLACK)
continue;
if (GRID(state,flags,s.points[i].x,s.points[i].y) & F_IMPOSSIBLE)
continue;
if (GRID(state,lights,s.points[i].x,s.points[i].y))
continue;
empty++;
}
return (n > lights || (n + empty < lights));
}
static bool number_correct(game_state *state, int x, int y)
{
surrounds s;
int n = 0, i, lights = GRID(state, lights, x, y);
assert(GRID(state, flags, x, y) & F_NUMBERED);
get_surrounds(state, x, y, &s);
for (i = 0; i < s.npoints; i++) {
if (GRID(state,flags,s.points[i].x,s.points[i].y) & F_LIGHT)
n++;
}
return n == lights;
}
/* Returns true if any numbers add up incorrectly. */
static bool grid_addsup(game_state *state)
{
int x, y;
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
if (!(GRID(state, flags, x, y) & F_NUMBERED)) continue;
if (!number_correct(state, x, y)) return false;
}
}
return true;
}
static bool grid_correct(game_state *state)
{
if (grid_lit(state) &&
!grid_overlap(state) &&
grid_addsup(state)) return true;
return false;
}
/* --- Board initial setup (blacks, lights, numbers) --- */
static void clean_board(game_state *state, bool leave_blacks)
{
int x,y;
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
if (leave_blacks)
GRID(state, flags, x, y) &= F_BLACK;
else
GRID(state, flags, x, y) = 0;
GRID(state, lights, x, y) = 0;
}
}
state->nlights = 0;
}
static void set_blacks(game_state *state, const game_params *params,
random_state *rs)
{
int x, y, degree = 0, nblack;
bool rotate = false;
int rh, rw, i;
int wodd = (state->w % 2) ? 1 : 0;
int hodd = (state->h % 2) ? 1 : 0;
int xs[4], ys[4];
switch (params->symm) {
case SYMM_NONE: degree = 1; rotate = false; break;
case SYMM_ROT2: degree = 2; rotate = true; break;
case SYMM_REF2: degree = 2; rotate = false; break;
case SYMM_ROT4: degree = 4; rotate = true; break;
case SYMM_REF4: degree = 4; rotate = false; break;
default: assert(!"Unknown symmetry type");
}
if (params->symm == SYMM_ROT4 && (state->h != state->w))
assert(!"4-fold symmetry unavailable without square grid");
if (degree == 4) {
rw = state->w/2;
rh = state->h/2;
if (!rotate) rw += wodd; /* ... but see below. */
rh += hodd;
} else if (degree == 2) {
rw = state->w;
rh = state->h/2;
rh += hodd;
} else {
rw = state->w;
rh = state->h;
}
/* clear, then randomise, required region. */
clean_board(state, false);
nblack = (rw * rh * params->blackpc) / 100;
for (i = 0; i < nblack; i++) {
do {
x = random_upto(rs,rw);
y = random_upto(rs,rh);
} while (GRID(state,flags,x,y) & F_BLACK);
GRID(state, flags, x, y) |= F_BLACK;
}
/* Copy required region. */
if (params->symm == SYMM_NONE) return;
for (x = 0; x < rw; x++) {
for (y = 0; y < rh; y++) {
if (degree == 4) {
xs[0] = x;
ys[0] = y;
xs[1] = state->w - 1 - (rotate ? y : x);
ys[1] = rotate ? x : y;
xs[2] = rotate ? (state->w - 1 - x) : x;
ys[2] = state->h - 1 - y;
xs[3] = rotate ? y : (state->w - 1 - x);
ys[3] = state->h - 1 - (rotate ? x : y);
} else {
xs[0] = x;
ys[0] = y;
xs[1] = rotate ? (state->w - 1 - x) : x;
ys[1] = state->h - 1 - y;
}
for (i = 1; i < degree; i++) {
GRID(state, flags, xs[i], ys[i]) =
GRID(state, flags, xs[0], ys[0]);
}
}
}
/* SYMM_ROT4 misses the middle square above; fix that here. */
if (degree == 4 && rotate && wodd &&
(random_upto(rs,100) <= (unsigned int)params->blackpc))
GRID(state,flags,
state->w/2 + wodd - 1, state->h/2 + hodd - 1) |= F_BLACK;
#ifdef SOLVER_DIAGNOSTICS
if (verbose) debug_state(state);
#endif
}
/* Fills in (does not allocate) a ll_data with all the tiles that would
* be illuminated by a light at point (ox,oy). If origin is true then the
* origin is included in this list. */
static void list_lights(game_state *state, int ox, int oy, bool origin,
ll_data *lld)
{
int x,y;
lld->ox = lld->minx = lld->maxx = ox;
lld->oy = lld->miny = lld->maxy = oy;
lld->include_origin = origin;
y = oy;
for (x = ox-1; x >= 0; x--) {
if (GRID(state, flags, x, y) & F_BLACK) break;
if (x < lld->minx) lld->minx = x;
}
for (x = ox+1; x < state->w; x++) {
if (GRID(state, flags, x, y) & F_BLACK) break;
if (x > lld->maxx) lld->maxx = x;
}
x = ox;
for (y = oy-1; y >= 0; y--) {
if (GRID(state, flags, x, y) & F_BLACK) break;
if (y < lld->miny) lld->miny = y;
}
for (y = oy+1; y < state->h; y++) {
if (GRID(state, flags, x, y) & F_BLACK) break;
if (y > lld->maxy) lld->maxy = y;
}
}
/* Makes sure a light is the given state, editing the lights table to suit the
* new state if necessary. */
static void set_light(game_state *state, int ox, int oy, bool on)
{
ll_data lld;
int diff = 0;
assert(!(GRID(state,flags,ox,oy) & F_BLACK));
if (!on && GRID(state,flags,ox,oy) & F_LIGHT) {
diff = -1;
GRID(state,flags,ox,oy) &= ~F_LIGHT;
state->nlights--;
} else if (on && !(GRID(state,flags,ox,oy) & F_LIGHT)) {
diff = 1;
GRID(state,flags,ox,oy) |= F_LIGHT;
state->nlights++;
}
if (diff != 0) {
list_lights(state,ox,oy,true,&lld);
FOREACHLIT(&lld, GRID(state,lights,lx,ly) += diff; );
}
}
/* Returns 1 if removing a light at (x,y) would cause a square to go dark. */
static int check_dark(game_state *state, int x, int y)
{
ll_data lld;
list_lights(state, x, y, true, &lld);
FOREACHLIT(&lld, if (GRID(state,lights,lx,ly) == 1) { return 1; } );
return 0;
}
/* Sets up an initial random correct position (i.e. every
* space lit, and no lights lit by other lights) by filling the
* grid with lights and then removing lights one by one at random. */
static void place_lights(game_state *state, random_state *rs)
{
int i, x, y, n, *numindices, wh = state->w*state->h;
ll_data lld;
numindices = snewn(wh, int);
for (i = 0; i < wh; i++) numindices[i] = i;
shuffle(numindices, wh, sizeof(*numindices), rs);
/* Place a light on all grid squares without lights. */
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
GRID(state, flags, x, y) &= ~F_MARK; /* we use this later. */
if (GRID(state, flags, x, y) & F_BLACK) continue;
set_light(state, x, y, true);
}
}
for (i = 0; i < wh; i++) {
y = numindices[i] / state->w;
x = numindices[i] % state->w;
if (!(GRID(state, flags, x, y) & F_LIGHT)) continue;
if (GRID(state, flags, x, y) & F_MARK) continue;
list_lights(state, x, y, false, &lld);
/* If we're not lighting any lights ourself, don't remove anything. */
n = 0;
FOREACHLIT(&lld, if (GRID(state,flags,lx,ly) & F_LIGHT) { n += 1; } );
if (n == 0) continue; /* [1] */
/* Check whether removing lights we're lighting would cause anything
* to go dark. */
n = 0;
FOREACHLIT(&lld, if (GRID(state,flags,lx,ly) & F_LIGHT) { n += check_dark(state,lx,ly); } );
if (n == 0) {
/* No, it wouldn't, so we can remove them all. */
FOREACHLIT(&lld, set_light(state,lx,ly, false); );
GRID(state,flags,x,y) |= F_MARK;
}
if (!grid_overlap(state)) {
sfree(numindices);
return; /* we're done. */
}
assert(grid_lit(state));
}
/* could get here if the line at [1] continue'd out of the loop. */
if (grid_overlap(state)) {
debug_state(state);
assert(!"place_lights failed to resolve overlapping lights!");
}
sfree(numindices);
}
/* Fills in all black squares with numbers of adjacent lights. */
static void place_numbers(game_state *state)
{
int x, y, i, n;
surrounds s;
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
if (!(GRID(state,flags,x,y) & F_BLACK)) continue;
get_surrounds(state, x, y, &s);
n = 0;
for (i = 0; i < s.npoints; i++) {
if (GRID(state,flags,s.points[i].x, s.points[i].y) & F_LIGHT)
n++;
}
GRID(state,flags,x,y) |= F_NUMBERED;
GRID(state,lights,x,y) = n;
}
}
}
/* --- Actual solver, with helper subroutines. --- */
static void tsl_callback(game_state *state,
int lx, int ly, int *x, int *y, int *n)
{
if (GRID(state,flags,lx,ly) & F_IMPOSSIBLE) return;
if (GRID(state,lights,lx,ly) > 0) return;
*x = lx; *y = ly; (*n)++;
}
static bool try_solve_light(game_state *state, int ox, int oy,
unsigned int flags, int lights)
{
ll_data lld;
int sx = 0, sy = 0, n = 0;
if (lights > 0) return false;
if (flags & F_BLACK) return false;
/* We have an unlit square; count how many ways there are left to
* place a light that lights us (including this square); if only
* one, we must put a light there. Squares that could light us
* are, of course, the same as the squares we would light... */
list_lights(state, ox, oy, true, &lld);
FOREACHLIT(&lld, { tsl_callback(state, lx, ly, &sx, &sy, &n); });
if (n == 1) {
set_light(state, sx, sy, true);
#ifdef SOLVER_DIAGNOSTICS
debug(("(%d,%d) can only be lit from (%d,%d); setting to LIGHT\n",
ox,oy,sx,sy));
if (verbose) debug_state(state);
#endif
return true;
}
return false;
}
static bool could_place_light(unsigned int flags, int lights)
{
if (flags & (F_BLACK | F_IMPOSSIBLE)) return false;
return !(lights > 0);
}
static bool could_place_light_xy(game_state *state, int x, int y)
{
int lights = GRID(state,lights,x,y);
unsigned int flags = GRID(state,flags,x,y);
return could_place_light(flags, lights);
}
/* For a given number square, determine whether we have enough info
* to unambiguously place its lights. */
static bool try_solve_number(game_state *state, int nx, int ny,
unsigned int nflags, int nlights)
{
surrounds s;
int x, y, nl, ns, i, lights;
bool ret = false;
unsigned int flags;
if (!(nflags & F_NUMBERED)) return false;
nl = nlights;
get_surrounds(state,nx,ny,&s);
ns = s.npoints;
/* nl is no. of lights we need to place, ns is no. of spaces we
* have to place them in. Try and narrow these down, and mark
* points we can ignore later. */
for (i = 0; i < s.npoints; i++) {
x = s.points[i].x; y = s.points[i].y;
flags = GRID(state,flags,x,y);
lights = GRID(state,lights,x,y);
if (flags & F_LIGHT) {
/* light here already; one less light for one less place. */
nl--; ns--;
s.points[i].f |= F_MARK;
} else if (!could_place_light(flags, lights)) {
ns--;
s.points[i].f |= F_MARK;
}
}
if (ns == 0) return false; /* nowhere to put anything. */
if (nl == 0) {
/* we have placed all lights we need to around here; all remaining
* surrounds are therefore IMPOSSIBLE. */
GRID(state,flags,nx,ny) |= F_NUMBERUSED;
for (i = 0; i < s.npoints; i++) {
if (!(s.points[i].f & F_MARK)) {
GRID(state,flags,s.points[i].x,s.points[i].y) |= F_IMPOSSIBLE;
ret = true;
}
}
#ifdef SOLVER_DIAGNOSTICS
printf("Clue at (%d,%d) full; setting unlit to IMPOSSIBLE.\n",
nx,ny);
if (verbose) debug_state(state);
#endif
} else if (nl == ns) {
/* we have as many lights to place as spaces; fill them all. */
GRID(state,flags,nx,ny) |= F_NUMBERUSED;
for (i = 0; i < s.npoints; i++) {
if (!(s.points[i].f & F_MARK)) {
set_light(state, s.points[i].x,s.points[i].y, true);
ret = true;
}
}
#ifdef SOLVER_DIAGNOSTICS
printf("Clue at (%d,%d) trivial; setting unlit to LIGHT.\n",
nx,ny);
if (verbose) debug_state(state);
#endif
}
return ret;
}
struct setscratch {
int x, y;
int n;
};
#define SCRATCHSZ (state->w+state->h)
/* New solver algorithm: overlapping sets can add IMPOSSIBLE flags.
* Algorithm thanks to Simon:
*
* (a) Any square where you can place a light has a set of squares
* which would become non-lights as a result. (This includes
* squares lit by the first square, and can also include squares
* adjacent to the same clue square if the new light is the last
* one around that clue.) Call this MAKESDARK(x,y) with (x,y) being
* the square you place a light.
* (b) Any unlit square has a set of squares on which you could place
* a light to illuminate it. (Possibly including itself, of
* course.) This set of squares has the property that _at least
* one_ of them must contain a light. Sets of this type also arise
* from clue squares. Call this MAKESLIGHT(x,y), again with (x,y)
* the square you would place a light.
* (c) If there exists (dx,dy) and (lx,ly) such that MAKESDARK(dx,dy) is
* a superset of MAKESLIGHT(lx,ly), this implies that placing a light at
* (dx,dy) would either leave no remaining way to illuminate a certain
* square, or would leave no remaining way to fulfill a certain clue
* (at lx,ly). In either case, a light can be ruled out at that position.
*
* So, we construct all possible MAKESLIGHT sets, both from unlit squares
* and clue squares, and then we look for plausible MAKESDARK sets that include
* our (lx,ly) to see if we can find a (dx,dy) to rule out. By the time we have
* constructed the MAKESLIGHT set we don't care about (lx,ly), just the set
* members.
*
* Once we have such a set, Simon came up with a Cunning Plan to find
* the most sensible MAKESDARK candidate:
*
* (a) for each square S in your set X, find all the squares which _would_
* rule it out. That means any square which would light S, plus
* any square adjacent to the same clue square as S (provided
* that clue square has only one remaining light to be placed).
* It's not hard to make this list. Don't do anything with this
* data at the moment except _count_ the squares.
* (b) Find the square S_min in the original set which has the
* _smallest_ number of other squares which would rule it out.
* (c) Find all the squares that rule out S_min (it's probably
* better to recompute this than to have stored it during step
* (a), since the CPU requirement is modest but the storage
* cost would get ugly.) For each of these squares, see if it
* rules out everything else in the set X. Any which does can
* be marked as not-a-light.
*
*/
typedef void (*trl_cb)(game_state *state, int dx, int dy,
struct setscratch *scratch, int n, void *ctx);
static void try_rule_out(game_state *state, int x, int y,
struct setscratch *scratch, int n,
trl_cb cb, void *ctx);
static void trl_callback_search(game_state *state, int dx, int dy,
struct setscratch *scratch, int n, void *ignored)
{
int i;
#ifdef SOLVER_DIAGNOSTICS
if (verbose) debug(("discount cb: light at (%d,%d)\n", dx, dy));
#endif
for (i = 0; i < n; i++) {
if (dx == scratch[i].x && dy == scratch[i].y) {
scratch[i].n = 1;
return;
}
}
}
static void trl_callback_discount(game_state *state, int dx, int dy,
struct setscratch *scratch, int n, void *ctx)
{
bool *didsth = (bool *)ctx;
int i;
if (GRID(state,flags,dx,dy) & F_IMPOSSIBLE) {
#ifdef SOLVER_DIAGNOSTICS
debug(("Square at (%d,%d) already impossible.\n", dx,dy));
#endif
return;
}
/* Check whether a light at (dx,dy) rules out everything
* in scratch, and mark (dx,dy) as IMPOSSIBLE if it does.
* We can use try_rule_out for this as well, as the set of
* squares which would rule out (x,y) is the same as the
* set of squares which (x,y) would rule out. */
#ifdef SOLVER_DIAGNOSTICS
if (verbose) debug(("Checking whether light at (%d,%d) rules out everything in scratch.\n", dx, dy));
#endif
for (i = 0; i < n; i++)
scratch[i].n = 0;
try_rule_out(state, dx, dy, scratch, n, trl_callback_search, NULL);
for (i = 0; i < n; i++) {
if (scratch[i].n == 0) return;
}
/* The light ruled out everything in scratch. Yay. */
GRID(state,flags,dx,dy) |= F_IMPOSSIBLE;
#ifdef SOLVER_DIAGNOSTICS
debug(("Set reduction discounted square at (%d,%d):\n", dx,dy));
if (verbose) debug_state(state);
#endif
*didsth = true;
}
static void trl_callback_incn(game_state *state, int dx, int dy,
struct setscratch *scratch, int n, void *ctx)
{
struct setscratch *s = (struct setscratch *)ctx;
s->n++;
}
static void try_rule_out(game_state *state, int x, int y,
struct setscratch *scratch, int n,
trl_cb cb, void *ctx)
{
/* XXX Find all the squares which would rule out (x,y); anything
* that would light it as well as squares adjacent to same clues
* as X assuming that clue only has one remaining light.
* Call the callback with each square. */
ll_data lld;
surrounds s, ss;
int i, j, curr_lights, tot_lights;
/* Find all squares that would rule out a light at (x,y) and call trl_cb
* with them: anything that would light (x,y)... */
list_lights(state, x, y, false, &lld);
FOREACHLIT(&lld, { if (could_place_light_xy(state, lx, ly)) { cb(state, lx, ly, scratch, n, ctx); } });
/* ... as well as any empty space (that isn't x,y) next to any clue square
* next to (x,y) that only has one light left to place. */
get_surrounds(state, x, y, &s);
for (i = 0; i < s.npoints; i++) {
if (!(GRID(state,flags,s.points[i].x,s.points[i].y) & F_NUMBERED))
continue;
/* we have an adjacent clue square; find /its/ surrounds
* and count the remaining lights it needs. */
get_surrounds(state,s.points[i].x,s.points[i].y,&ss);
curr_lights = 0;
for (j = 0; j < ss.npoints; j++) {
if (GRID(state,flags,ss.points[j].x,ss.points[j].y) & F_LIGHT)
curr_lights++;
}
tot_lights = GRID(state, lights, s.points[i].x, s.points[i].y);
/* We have a clue with tot_lights to fill, and curr_lights currently
* around it. If adding a light at (x,y) fills up the clue (i.e.
* curr_lights + 1 = tot_lights) then we need to discount all other
* unlit squares around the clue. */
if ((curr_lights + 1) == tot_lights) {
for (j = 0; j < ss.npoints; j++) {
int lx = ss.points[j].x, ly = ss.points[j].y;
if (lx == x && ly == y) continue;
if (could_place_light_xy(state, lx, ly))
cb(state, lx, ly, scratch, n, ctx);
}
}
}
}
#ifdef SOLVER_DIAGNOSTICS
static void debug_scratch(const char *msg, struct setscratch *scratch, int n)
{
int i;
debug(("%s scratch (%d elements):\n", msg, n));
for (i = 0; i < n; i++) {
debug((" (%d,%d) n%d\n", scratch[i].x, scratch[i].y, scratch[i].n));
}
}
#endif
static bool discount_set(game_state *state,
struct setscratch *scratch, int n)
{
int i, besti, bestn;
bool didsth = false;
#ifdef SOLVER_DIAGNOSTICS
if (verbose > 1) debug_scratch("discount_set", scratch, n);
#endif
if (n == 0) return false;
for (i = 0; i < n; i++) {
try_rule_out(state, scratch[i].x, scratch[i].y, scratch, n,
trl_callback_incn, (void*)&(scratch[i]));
}
#ifdef SOLVER_DIAGNOSTICS
if (verbose > 1) debug_scratch("discount_set after count", scratch, n);
#endif
besti = -1; bestn = SCRATCHSZ;
for (i = 0; i < n; i++) {
if (scratch[i].n < bestn) {
bestn = scratch[i].n;
besti = i;
}
}
#ifdef SOLVER_DIAGNOSTICS
if (verbose > 1) debug(("best square (%d,%d) with n%d.\n",
scratch[besti].x, scratch[besti].y, scratch[besti].n));
#endif
try_rule_out(state, scratch[besti].x, scratch[besti].y, scratch, n,
trl_callback_discount, (void*)&didsth);
#ifdef SOLVER_DIAGNOSTICS
if (didsth) debug((" [from square (%d,%d)]\n",
scratch[besti].x, scratch[besti].y));
#endif
return didsth;
}
static void discount_clear(game_state *state, struct setscratch *scratch, int *n)
{
*n = 0;
memset(scratch, 0, SCRATCHSZ * sizeof(struct setscratch));
}
static void unlit_cb(game_state *state, int lx, int ly,
struct setscratch *scratch, int *n)
{
if (could_place_light_xy(state, lx, ly)) {
scratch[*n].x = lx; scratch[*n].y = ly; (*n)++;
}
}
/* Construct a MAKESLIGHT set from an unlit square. */
static bool discount_unlit(game_state *state, int x, int y,
struct setscratch *scratch)
{
ll_data lld;
int n;
bool didsth;
#ifdef SOLVER_DIAGNOSTICS
if (verbose) debug(("Trying to discount for unlit square at (%d,%d).\n", x, y));
if (verbose > 1) debug_state(state);
#endif
discount_clear(state, scratch, &n);
list_lights(state, x, y, true, &lld);
FOREACHLIT(&lld, { unlit_cb(state, lx, ly, scratch, &n); });
didsth = discount_set(state, scratch, n);
#ifdef SOLVER_DIAGNOSTICS
if (didsth) debug((" [from unlit square at (%d,%d)].\n", x, y));
#endif
return didsth;
}
/* Construct a series of MAKESLIGHT sets from a clue square.
* for a clue square with N remaining spaces that must contain M lights, every
* subset of size N-M+1 of those N spaces forms such a set.
*/
static bool discount_clue(game_state *state, int x, int y,
struct setscratch *scratch)
{
int slen, m = GRID(state, lights, x, y), n, i, lights;
bool didsth = false;
unsigned int flags;
surrounds s, sempty;
combi_ctx *combi;
if (m == 0) return false;
#ifdef SOLVER_DIAGNOSTICS
if (verbose) debug(("Trying to discount for sets at clue (%d,%d).\n", x, y));
if (verbose > 1) debug_state(state);
#endif
/* m is no. of lights still to place; starts off at the clue value
* and decreases when we find a light already down.
* n is no. of spaces left; starts off at 0 and goes up when we find
* a plausible space. */
get_surrounds(state, x, y, &s);
memset(&sempty, 0, sizeof(surrounds));
for (i = 0; i < s.npoints; i++) {
int lx = s.points[i].x, ly = s.points[i].y;
flags = GRID(state,flags,lx,ly);
lights = GRID(state,lights,lx,ly);
if (flags & F_LIGHT) m--;
if (could_place_light(flags, lights)) {
sempty.points[sempty.npoints].x = lx;
sempty.points[sempty.npoints].y = ly;
sempty.npoints++;
}
}
n = sempty.npoints; /* sempty is now a surrounds of only blank squares. */
if (n == 0) return false; /* clue is full already. */
if (m < 0 || m > n) return false; /* become impossible. */
combi = new_combi(n - m + 1, n);
while (next_combi(combi)) {
discount_clear(state, scratch, &slen);
for (i = 0; i < combi->r; i++) {
scratch[slen].x = sempty.points[combi->a[i]].x;
scratch[slen].y = sempty.points[combi->a[i]].y;
slen++;
}
if (discount_set(state, scratch, slen)) didsth = true;
}
free_combi(combi);
#ifdef SOLVER_DIAGNOSTICS
if (didsth) debug((" [from clue at (%d,%d)].\n", x, y));
#endif
return didsth;
}
#define F_SOLVE_FORCEUNIQUE 1
#define F_SOLVE_DISCOUNTSETS 2
#define F_SOLVE_ALLOWRECURSE 4
static unsigned int flags_from_difficulty(int difficulty)
{
unsigned int sflags = F_SOLVE_FORCEUNIQUE;
assert(difficulty <= DIFFCOUNT);
if (difficulty >= 1) sflags |= F_SOLVE_DISCOUNTSETS;
if (difficulty >= 2) sflags |= F_SOLVE_ALLOWRECURSE;
return sflags;
}
#define MAXRECURSE 5
static int solve_sub(game_state *state,
unsigned int solve_flags, int depth,
int *maxdepth)
{
unsigned int flags;
int x, y, ncanplace, lights;
bool didstuff;
int bestx, besty, n, bestn, copy_soluble, self_soluble, ret, maxrecurse = 0;
game_state *scopy;
ll_data lld;
struct setscratch *sscratch = NULL;
#ifdef SOLVER_DIAGNOSTICS
printf("solve_sub: depth = %d\n", depth);
#endif
if (maxdepth && *maxdepth < depth) *maxdepth = depth;
if (solve_flags & F_SOLVE_ALLOWRECURSE) maxrecurse = MAXRECURSE;
while (1) {
if (grid_overlap(state)) {
/* Our own solver, from scratch, should never cause this to happen
* (assuming a soluble grid). However, if we're trying to solve
* from a half-completed *incorrect* grid this might occur; we
* just return the 'no solutions' code in this case. */
ret = 0; goto done;
}
if (grid_correct(state)) { ret = 1; goto done; }
ncanplace = 0;
didstuff = false;
/* These 2 loops, and the functions they call, are the critical loops
* for timing; any optimisations should look here first. */
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
flags = GRID(state,flags,x,y);
lights = GRID(state,lights,x,y);
ncanplace += could_place_light(flags, lights);
if (try_solve_light(state, x, y, flags, lights))
didstuff = true;
if (try_solve_number(state, x, y, flags, lights))
didstuff = true;
}
}
if (didstuff) continue;
if (!ncanplace) {
/* nowhere to put a light, puzzle is unsoluble. */
ret = 0; goto done;
}
if (solve_flags & F_SOLVE_DISCOUNTSETS) {
if (!sscratch) sscratch = snewn(SCRATCHSZ, struct setscratch);
/* Try a more cunning (and more involved) way... more details above. */
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
flags = GRID(state,flags,x,y);
lights = GRID(state,lights,x,y);
if (!(flags & F_BLACK) && lights == 0) {
if (discount_unlit(state, x, y, sscratch)) {
didstuff = true;
goto reduction_success;
}
} else if (flags & F_NUMBERED) {
if (discount_clue(state, x, y, sscratch)) {
didstuff = true;
goto reduction_success;
}
}
}
}
}
reduction_success:
if (didstuff) continue;
/* We now have to make a guess; we have places to put lights but
* no definite idea about where they can go. */
if (depth >= maxrecurse) {
/* mustn't delve any deeper. */
ret = -1; goto done;
}
/* Of all the squares that we could place a light, pick the one
* that would light the most currently unlit squares. */
/* This heuristic was just plucked from the air; there may well be
* a more efficient way of choosing a square to flip to minimise
* recursion. */
bestn = 0;
bestx = besty = -1; /* suyb */
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
flags = GRID(state,flags,x,y);
lights = GRID(state,lights,x,y);
if (!could_place_light(flags, lights)) continue;
n = 0;
list_lights(state, x, y, true, &lld);
FOREACHLIT(&lld, { if (GRID(state,lights,lx,ly) == 0) n++; });
if (n > bestn) {
bestn = n; bestx = x; besty = y;
}
}
}
assert(bestn > 0);
assert(bestx >= 0 && besty >= 0);
/* Now we've chosen a plausible (x,y), try to solve it once as 'lit'
* and once as 'impossible'; we need to make one copy to do this. */
scopy = dup_game(state);
#ifdef SOLVER_DIAGNOSTICS
debug(("Recursing #1: trying (%d,%d) as IMPOSSIBLE\n", bestx, besty));
#endif
GRID(state,flags,bestx,besty) |= F_IMPOSSIBLE;
self_soluble = solve_sub(state, solve_flags, depth+1, maxdepth);
if (!(solve_flags & F_SOLVE_FORCEUNIQUE) && self_soluble > 0) {
/* we didn't care about finding all solutions, and we just
* found one; return with it immediately. */
free_game(scopy);
ret = self_soluble;
goto done;
}
#ifdef SOLVER_DIAGNOSTICS
debug(("Recursing #2: trying (%d,%d) as LIGHT\n", bestx, besty));
#endif
set_light(scopy, bestx, besty, true);
copy_soluble = solve_sub(scopy, solve_flags, depth+1, maxdepth);
/* If we wanted a unique solution but we hit our recursion limit
* (on either branch) then we have to assume we didn't find possible
* extra solutions, and return 'not soluble'. */
if ((solve_flags & F_SOLVE_FORCEUNIQUE) &&
((copy_soluble < 0) || (self_soluble < 0))) {
ret = -1;
/* Make sure that whether or not it was self or copy (or both) that
* were soluble, that we return a solved state in self. */
} else if (copy_soluble <= 0) {
/* copy wasn't soluble; keep self state and return that result. */
ret = self_soluble;
} else if (self_soluble <= 0) {
/* copy solved and we didn't, so copy in copy's (now solved)
* flags and light state. */
memcpy(state->lights, scopy->lights,
scopy->w * scopy->h * sizeof(int));
memcpy(state->flags, scopy->flags,
scopy->w * scopy->h * sizeof(unsigned int));
ret = copy_soluble;
} else {
ret = copy_soluble + self_soluble;
}
free_game(scopy);
goto done;
}
done:
if (sscratch) sfree(sscratch);
#ifdef SOLVER_DIAGNOSTICS
if (ret < 0)
debug(("solve_sub: depth = %d returning, ran out of recursion.\n",
depth));
else
debug(("solve_sub: depth = %d returning, %d solutions.\n",
depth, ret));
#endif
return ret;
}
/* Fills in the (possibly partially-complete) game_state as far as it can,
* returning the number of possible solutions. If it returns >0 then the
* game_state will be in a solved state, but you won't know which one. */
static int dosolve(game_state *state, int solve_flags, int *maxdepth)
{
int x, y, nsol;
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
GRID(state,flags,x,y) &= ~F_NUMBERUSED;
}
}
nsol = solve_sub(state, solve_flags, 0, maxdepth);
return nsol;
}
static int strip_unused_nums(game_state *state)
{
int x,y,n=0;
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
if ((GRID(state,flags,x,y) & F_NUMBERED) &&
!(GRID(state,flags,x,y) & F_NUMBERUSED)) {
GRID(state,flags,x,y) &= ~F_NUMBERED;
GRID(state,lights,x,y) = 0;
n++;
}
}
}
debug(("Stripped %d unused numbers.\n", n));
return n;
}
static void unplace_lights(game_state *state)
{
int x,y;
for (x = 0; x < state->w; x++) {
for (y = 0; y < state->h; y++) {
if (GRID(state,flags,x,y) & F_LIGHT)
set_light(state,x,y,false);
GRID(state,flags,x,y) &= ~F_IMPOSSIBLE;
GRID(state,flags,x,y) &= ~F_NUMBERUSED;
}
}
}
static bool puzzle_is_good(game_state *state, int difficulty)
{
int nsol, mdepth = 0;
unsigned int sflags = flags_from_difficulty(difficulty);
unplace_lights(state);
#ifdef SOLVER_DIAGNOSTICS
debug(("Trying to solve with difficulty %d (0x%x):\n",
difficulty, sflags));
if (verbose) debug_state(state);
#endif
nsol = dosolve(state, sflags, &mdepth);
/* if we wanted an easy puzzle, make sure we didn't need recursion. */
if (!(sflags & F_SOLVE_ALLOWRECURSE) && mdepth > 0) {
debug(("Ignoring recursive puzzle.\n"));
return false;
}
debug(("%d solutions found.\n", nsol));
if (nsol <= 0) return false;
if (nsol > 1) return false;
return true;
}
/* --- New game creation and user input code. --- */
/* The basic algorithm here is to generate the most complex grid possible
* while honouring two restrictions:
*
* * we require a unique solution, and
* * either we require solubility with no recursion (!params->recurse)
* * or we require some recursion. (params->recurse).
*
* The solver helpfully keeps track of the numbers it needed to use to
* get its solution, so we use that to remove an initial set of numbers
* and check we still satsify our requirements (on uniqueness and
* non-recursiveness, if applicable; we don't check explicit recursiveness
* until the end).
*
* Then we try to remove all numbers in a random order, and see if we
* still satisfy requirements (putting them back if we didn't).
*
* Removing numbers will always, in general terms, make a puzzle require
* more recursion but it may also mean a puzzle becomes non-unique.
*
* Once we're done, if we wanted a recursive puzzle but the most difficult
* puzzle we could come up with was non-recursive, we give up and try a new
* grid. */
#define MAX_GRIDGEN_TRIES 20
static char *new_game_desc(const game_params *params_in, random_state *rs,
char **aux, bool interactive)
{
game_params params_copy = *params_in; /* structure copy */
game_params *params = ¶ms_copy;
game_state *news = new_state(params), *copys;
int i, j, run, x, y, wh = params->w*params->h, num;
char *ret, *p;
int *numindices;
/* Construct a shuffled list of grid positions; we only
* do this once, because if it gets used more than once it'll
* be on a different grid layout. */
numindices = snewn(wh, int);
for (j = 0; j < wh; j++) numindices[j] = j;
shuffle(numindices, wh, sizeof(*numindices), rs);
while (1) {
for (i = 0; i < MAX_GRIDGEN_TRIES; i++) {
set_blacks(news, params, rs); /* also cleans board. */
/* set up lights and then the numbers, and remove the lights */
place_lights(news, rs);
debug(("Generating initial grid.\n"));
place_numbers(news);
if (!puzzle_is_good(news, params->difficulty)) continue;
/* Take a copy, remove numbers we didn't use and check there's
* still a unique solution; if so, use the copy subsequently. */
copys = dup_game(news);
strip_unused_nums(copys);
if (!puzzle_is_good(copys, params->difficulty)) {
debug(("Stripped grid is not good, reverting.\n"));
free_game(copys);
} else {
free_game(news);
news = copys;
}
/* Go through grid removing numbers at random one-by-one and
* trying to solve again; if it ceases to be good put the number back. */
for (j = 0; j < wh; j++) {
y = numindices[j] / params->w;
x = numindices[j] % params->w;
if (!(GRID(news, flags, x, y) & F_NUMBERED)) continue;
num = GRID(news, lights, x, y);
GRID(news, lights, x, y) = 0;
GRID(news, flags, x, y) &= ~F_NUMBERED;
if (!puzzle_is_good(news, params->difficulty)) {
GRID(news, lights, x, y) = num;
GRID(news, flags, x, y) |= F_NUMBERED;
} else
debug(("Removed (%d,%d) still soluble.\n", x, y));
}
if (params->difficulty > 0) {
/* Was the maximally-difficult puzzle difficult enough?
* Check we can't solve it with a more simplistic solver. */
if (puzzle_is_good(news, params->difficulty-1)) {
debug(("Maximally-hard puzzle still not hard enough, skipping.\n"));
continue;
}
}
goto goodpuzzle;
}
/* Couldn't generate a good puzzle in however many goes. Ramp up the
* %age of black squares (if we didn't already have lots; in which case
* why couldn't we generate a puzzle?) and try again. */
if (params->blackpc < 90) params->blackpc += 5;
debug(("New black layout %d%%.\n", params->blackpc));
}
goodpuzzle:
/* Game is encoded as a long string one character per square;
* 'S' is a space
* 'B' is a black square with no number
* '0', '1', '2', '3', '4' is a black square with a number. */
ret = snewn((params->w * params->h) + 1, char);
p = ret;
run = 0;
for (y = 0; y < params->h; y++) {
for (x = 0; x < params->w; x++) {
if (GRID(news,flags,x,y) & F_BLACK) {
if (run) {
*p++ = ('a'-1) + run;
run = 0;
}
if (GRID(news,flags,x,y) & F_NUMBERED)
*p++ = '0' + GRID(news,lights,x,y);
else
*p++ = 'B';
} else {
if (run == 26) {
*p++ = ('a'-1) + run;
run = 0;
}
run++;
}
}
}
if (run) {
*p++ = ('a'-1) + run;
run = 0;
}
*p = '\0';
assert(p - ret <= params->w * params->h);
free_game(news);
sfree(numindices);
return ret;
}
static const char *validate_desc(const game_params *params, const char *desc)
{
int i;
for (i = 0; i < params->w*params->h; i++) {
if (*desc >= '0' && *desc <= '4')
/* OK */;
else if (*desc == 'B')
/* OK */;
else if (*desc >= 'a' && *desc <= 'z')
i += *desc - 'a'; /* and the i++ will add another one */
else if (!*desc)
return "Game description shorter than expected";
else
return "Game description contained unexpected character";
desc++;
}
if (*desc || i > params->w*params->h)
return "Game description longer than expected";
return NULL;
}
static game_state *new_game(midend *me, const game_params *params,
const char *desc)
{
game_state *ret = new_state(params);
int x,y;
int run = 0;
for (y = 0; y < params->h; y++) {
for (x = 0; x < params->w; x++) {
char c = '\0';
if (run == 0) {
c = *desc++;
assert(c != 'S');
if (c >= 'a' && c <= 'z')
run = c - 'a' + 1;
}
if (run > 0) {
c = 'S';
run--;
}
switch (c) {
case '0': case '1': case '2': case '3': case '4':
GRID(ret,flags,x,y) |= F_NUMBERED;
GRID(ret,lights,x,y) = (c - '0');
/* run-on... */
case 'B':
GRID(ret,flags,x,y) |= F_BLACK;
break;
case 'S':
/* empty square */
break;
default:
assert(!"Malformed desc.");
break;
}
}
}
if (*desc) assert(!"Over-long desc.");
return ret;
}
static char *solve_game(const game_state *state, const game_state *currstate,
const char *aux, const char **error)
{
game_state *solved;
char *move = NULL, buf[80];
int movelen, movesize, x, y, len;
unsigned int oldflags, solvedflags, sflags;
/* We don't care here about non-unique puzzles; if the
* user entered one themself then I doubt they care. */
sflags = F_SOLVE_ALLOWRECURSE | F_SOLVE_DISCOUNTSETS;
/* Try and solve from where we are now (for non-unique
* puzzles this may produce a different answer). */
solved = dup_game(currstate);
if (dosolve(solved, sflags, NULL) > 0) goto solved;
free_game(solved);
/* That didn't work; try solving from the clean puzzle. */
solved = dup_game(state);
if (dosolve(solved, sflags, NULL) > 0) goto solved;
*error = "Unable to find a solution to this puzzle.";
goto done;
solved:
movesize = 256;
move = snewn(movesize, char);
movelen = 0;
move[movelen++] = 'S';
move[movelen] = '\0';
for (x = 0; x < currstate->w; x++) {
for (y = 0; y < currstate->h; y++) {
len = 0;
oldflags = GRID(currstate, flags, x, y);
solvedflags = GRID(solved, flags, x, y);
if ((oldflags & F_LIGHT) != (solvedflags & F_LIGHT))
len = sprintf(buf, ";L%d,%d", x, y);
else if ((oldflags & F_IMPOSSIBLE) != (solvedflags & F_IMPOSSIBLE))
len = sprintf(buf, ";I%d,%d", x, y);
if (len) {
if (movelen + len >= movesize) {
movesize = movelen + len + 256;
move = sresize(move, movesize, char);
}
strcpy(move + movelen, buf);
movelen += len;
}
}
}
done:
free_game(solved);
return move;
}
static bool game_can_format_as_text_now(const game_params *params)
{
return true;
}
/* 'borrowed' from slant.c, mainly. I could have printed it one
* character per cell (like debug_state) but that comes out tiny.
* 'L' is used for 'light here' because 'O' looks too much like '0'
* (black square with no surrounding lights). */
static char *game_text_format(const game_state *state)
{
int w = state->w, h = state->h, W = w+1, H = h+1;
int x, y, len, lights;
unsigned int flags;
char *ret, *p;
len = (h+H) * (w+W+1) + 1;
ret = snewn(len, char);
p = ret;
for (y = 0; y < H; y++) {
for (x = 0; x < W; x++) {
*p++ = '+';
if (x < w)
*p++ = '-';
}
*p++ = '\n';
if (y < h) {
for (x = 0; x < W; x++) {
*p++ = '|';
if (x < w) {
/* actual interesting bit. */
flags = GRID(state, flags, x, y);
lights = GRID(state, lights, x, y);
if (flags & F_BLACK) {
if (flags & F_NUMBERED)
*p++ = '0' + lights;
else
*p++ = '#';
} else {
if (flags & F_LIGHT)
*p++ = 'L';
else if (flags & F_IMPOSSIBLE)
*p++ = 'x';
else if (lights > 0)
*p++ = '.';
else
*p++ = ' ';
}
}
}
*p++ = '\n';
}
}
*p++ = '\0';
assert(p - ret == len);
return ret;
}
struct game_ui {
int cur_x, cur_y;
bool cur_visible;
};
static game_ui *new_ui(const game_state *state)
{
game_ui *ui = snew(game_ui);
ui->cur_x = ui->cur_y = 0;
ui->cur_visible = false;
return ui;
}
static void free_ui(game_ui *ui)
{
sfree(ui);
}
static char *encode_ui(const game_ui *ui)
{
/* nothing to encode. */
return NULL;
}
static void decode_ui(game_ui *ui, const char *encoding)
{
/* nothing to decode. */
}
static void game_changed_state(game_ui *ui, const game_state *oldstate,
const game_state *newstate)
{
if (newstate->completed)
ui->cur_visible = false;
}
#define DF_BLACK 1 /* black square */
#define DF_NUMBERED 2 /* black square with number */
#define DF_LIT 4 /* display (white) square lit up */
#define DF_LIGHT 8 /* display light in square */
#define DF_OVERLAP 16 /* display light as overlapped */
#define DF_CURSOR 32 /* display cursor */
#define DF_NUMBERWRONG 64 /* display black numbered square as error. */
#define DF_FLASH 128 /* background flash is on. */
#define DF_IMPOSSIBLE 256 /* display non-light little square */
struct game_drawstate {
int tilesize, crad;
int w, h;
unsigned int *flags; /* width * height */
bool started;
};
/* Believe it or not, this empty = "" hack is needed to get around a bug in
* the prc-tools gcc when optimisation is turned on; before, it produced:
lightup-sect.c: In function `interpret_move':
lightup-sect.c:1416: internal error--unrecognizable insn:
(insn 582 580 583 (set (reg:SI 134)
(pc)) -1 (nil)
(nil))
*/
static char *interpret_move(const game_state *state, game_ui *ui,
const game_drawstate *ds,
int x, int y, int button)
{
enum { NONE, FLIP_LIGHT, FLIP_IMPOSSIBLE } action = NONE;
int cx = -1, cy = -1;
unsigned int flags;
char buf[80], *nullret = UI_UPDATE, *empty = UI_UPDATE, c;
if (button == LEFT_BUTTON || button == RIGHT_BUTTON) {
if (ui->cur_visible)
nullret = empty;
ui->cur_visible = false;
cx = FROMCOORD(x);
cy = FROMCOORD(y);
action = (button == LEFT_BUTTON) ? FLIP_LIGHT : FLIP_IMPOSSIBLE;
} else if (IS_CURSOR_SELECT(button) ||
button == 'i' || button == 'I') {
if (ui->cur_visible) {
/* Only allow cursor-effect operations if the cursor is visible
* (otherwise you have no idea which square it might be affecting) */
cx = ui->cur_x;
cy = ui->cur_y;
action = (button == 'i' || button == 'I' || button == CURSOR_SELECT2) ?
FLIP_IMPOSSIBLE : FLIP_LIGHT;
}
ui->cur_visible = true;
} else if (IS_CURSOR_MOVE(button)) {
move_cursor(button, &ui->cur_x, &ui->cur_y, state->w, state->h, false);
ui->cur_visible = true;
nullret = empty;
} else
return NULL;
switch (action) {
case FLIP_LIGHT:
case FLIP_IMPOSSIBLE:
if (cx < 0 || cy < 0 || cx >= state->w || cy >= state->h)
return nullret;
flags = GRID(state, flags, cx, cy);
if (flags & F_BLACK)
return nullret;
if (action == FLIP_LIGHT) {
#ifdef STYLUS_BASED
if (flags & F_IMPOSSIBLE || flags & F_LIGHT) c = 'I'; else c = 'L';
#else
if (flags & F_IMPOSSIBLE) return nullret;
c = 'L';
#endif
} else {
#ifdef STYLUS_BASED
if (flags & F_IMPOSSIBLE || flags & F_LIGHT) c = 'L'; else c = 'I';
#else
if (flags & F_LIGHT) return nullret;
c = 'I';
#endif
}
sprintf(buf, "%c%d,%d", (int)c, cx, cy);
break;
case NONE:
return nullret;
default:
assert(!"Shouldn't get here!");
}
return dupstr(buf);
}
static game_state *execute_move(const game_state *state, const char *move)
{
game_state *ret = dup_game(state);
int x, y, n, flags;
char c;
if (!*move) goto badmove;
while (*move) {
c = *move;
if (c == 'S') {
ret->used_solve = true;
move++;
} else if (c == 'L' || c == 'I') {
move++;
if (sscanf(move, "%d,%d%n", &x, &y, &n) != 2 ||
x < 0 || y < 0 || x >= ret->w || y >= ret->h)
goto badmove;
flags = GRID(ret, flags, x, y);
if (flags & F_BLACK) goto badmove;
/* LIGHT and IMPOSSIBLE are mutually exclusive. */
if (c == 'L') {
GRID(ret, flags, x, y) &= ~F_IMPOSSIBLE;
set_light(ret, x, y, !(flags & F_LIGHT));
} else {
set_light(ret, x, y, false);
GRID(ret, flags, x, y) ^= F_IMPOSSIBLE;
}
move += n;
} else goto badmove;
if (*move == ';')
move++;
else if (*move) goto badmove;
}
if (grid_correct(ret)) ret->completed = true;
return ret;
badmove:
free_game(ret);
return NULL;
}
/* ----------------------------------------------------------------------
* Drawing routines.
*/
/* XXX entirely cloned from fifteen.c; separate out? */
static void game_compute_size(const game_params *params, int tilesize,
int *x, int *y)
{
/* Ick: fake up `ds->tilesize' for macro expansion purposes */
struct { int tilesize; } ads, *ds = &ads;
ads.tilesize = tilesize;
*x = TILE_SIZE * params->w + 2 * BORDER;
*y = TILE_SIZE * params->h + 2 * BORDER;
}
static void game_set_size(drawing *dr, game_drawstate *ds,
const game_params *params, int tilesize)
{
ds->tilesize = tilesize;
ds->crad = 3*(tilesize-1)/8;
}
static float *game_colours(frontend *fe, int *ncolours)
{
float *ret = snewn(3 * NCOLOURS, float);
int i;
frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
for (i = 0; i < 3; i++) {
ret[COL_BLACK * 3 + i] = 0.0F;
ret[COL_LIGHT * 3 + i] = 1.0F;
ret[COL_CURSOR * 3 + i] = ret[COL_BACKGROUND * 3 + i] / 2.0F;
ret[COL_GRID * 3 + i] = ret[COL_BACKGROUND * 3 + i] / 1.5F;
}
ret[COL_ERROR * 3 + 0] = 1.0F;
ret[COL_ERROR * 3 + 1] = 0.25F;
ret[COL_ERROR * 3 + 2] = 0.25F;
ret[COL_LIT * 3 + 0] = 1.0F;
ret[COL_LIT * 3 + 1] = 1.0F;
ret[COL_LIT * 3 + 2] = 0.0F;
*ncolours = NCOLOURS;
return ret;
}
static game_drawstate *game_new_drawstate(drawing *dr, const game_state *state)
{
struct game_drawstate *ds = snew(struct game_drawstate);
int i;
ds->tilesize = ds->crad = 0;
ds->w = state->w; ds->h = state->h;
ds->flags = snewn(ds->w*ds->h, unsigned int);
for (i = 0; i < ds->w*ds->h; i++)
ds->flags[i] = -1;
ds->started = false;
return ds;
}
static void game_free_drawstate(drawing *dr, game_drawstate *ds)
{
sfree(ds->flags);
sfree(ds);
}
/* At some stage we should put these into a real options struct.
* Note that tile_redraw has no #ifdeffery; it relies on tile_flags not
* to put those flags in. */
#define HINT_LIGHTS
#define HINT_OVERLAPS
#define HINT_NUMBERS
static unsigned int tile_flags(game_drawstate *ds, const game_state *state,
const game_ui *ui, int x, int y, bool flashing)
{
unsigned int flags = GRID(state, flags, x, y);
int lights = GRID(state, lights, x, y);
unsigned int ret = 0;
if (flashing) ret |= DF_FLASH;
if (ui && ui->cur_visible && x == ui->cur_x && y == ui->cur_y)
ret |= DF_CURSOR;
if (flags & F_BLACK) {
ret |= DF_BLACK;
if (flags & F_NUMBERED) {
#ifdef HINT_NUMBERS
if (number_wrong(state, x, y))
ret |= DF_NUMBERWRONG;
#endif
ret |= DF_NUMBERED;
}
} else {
#ifdef HINT_LIGHTS
if (lights > 0) ret |= DF_LIT;
#endif
if (flags & F_LIGHT) {
ret |= DF_LIGHT;
#ifdef HINT_OVERLAPS
if (lights > 1) ret |= DF_OVERLAP;
#endif
}
if (flags & F_IMPOSSIBLE) ret |= DF_IMPOSSIBLE;
}
return ret;
}
static void tile_redraw(drawing *dr, game_drawstate *ds,
const game_state *state, int x, int y)
{
unsigned int ds_flags = GRID(ds, flags, x, y);
int dx = COORD(x), dy = COORD(y);
int lit = (ds_flags & DF_FLASH) ? COL_GRID : COL_LIT;
if (ds_flags & DF_BLACK) {
draw_rect(dr, dx, dy, TILE_SIZE, TILE_SIZE, COL_BLACK);
if (ds_flags & DF_NUMBERED) {
int ccol = (ds_flags & DF_NUMBERWRONG) ? COL_ERROR : COL_LIGHT;
char str[32];
/* We know that this won't change over the course of the game
* so it's OK to ignore this when calculating whether or not
* to redraw the tile. */
sprintf(str, "%d", GRID(state, lights, x, y));
draw_text(dr, dx + TILE_SIZE/2, dy + TILE_SIZE/2,
FONT_VARIABLE, TILE_SIZE*3/5,
ALIGN_VCENTRE | ALIGN_HCENTRE, ccol, str);
}
} else {
draw_rect(dr, dx, dy, TILE_SIZE, TILE_SIZE,
(ds_flags & DF_LIT) ? lit : COL_BACKGROUND);
draw_rect_outline(dr, dx, dy, TILE_SIZE, TILE_SIZE, COL_GRID);
if (ds_flags & DF_LIGHT) {
int lcol = (ds_flags & DF_OVERLAP) ? COL_ERROR : COL_LIGHT;
draw_circle(dr, dx + TILE_SIZE/2, dy + TILE_SIZE/2, TILE_RADIUS,
lcol, COL_BLACK);
} else if ((ds_flags & DF_IMPOSSIBLE)) {
static int draw_blobs_when_lit = -1;
if (draw_blobs_when_lit < 0) {
char *env = getenv("LIGHTUP_LIT_BLOBS");
draw_blobs_when_lit = (!env || (env[0] == 'y' ||
env[0] == 'Y'));
}
if (!(ds_flags & DF_LIT) || draw_blobs_when_lit) {
int rlen = TILE_SIZE / 4;
draw_rect(dr, dx + TILE_SIZE/2 - rlen/2,
dy + TILE_SIZE/2 - rlen/2,
rlen, rlen, COL_BLACK);
}
}
}
if (ds_flags & DF_CURSOR) {
int coff = TILE_SIZE/8;
draw_rect_outline(dr, dx + coff, dy + coff,
TILE_SIZE - coff*2, TILE_SIZE - coff*2, COL_CURSOR);
}
draw_update(dr, dx, dy, TILE_SIZE, TILE_SIZE);
}
static void game_redraw(drawing *dr, game_drawstate *ds,
const game_state *oldstate, const game_state *state,
int dir, const game_ui *ui,
float animtime, float flashtime)
{
bool flashing = false;
int x,y;
if (flashtime) flashing = (int)(flashtime * 3 / FLASH_TIME) != 1;
if (!ds->started) {
draw_rect_outline(dr, COORD(0)-1, COORD(0)-1,
TILE_SIZE * ds->w + 2,
TILE_SIZE * ds->h + 2,
COL_GRID);
draw_update(dr, 0, 0,
TILE_SIZE * ds->w + 2 * BORDER,
TILE_SIZE * ds->h + 2 * BORDER);
ds->started = true;
}
for (x = 0; x < ds->w; x++) {
for (y = 0; y < ds->h; y++) {
unsigned int ds_flags = tile_flags(ds, state, ui, x, y, flashing);
if (ds_flags != GRID(ds, flags, x, y)) {
GRID(ds, flags, x, y) = ds_flags;
tile_redraw(dr, ds, state, x, y);
}
}
}
}
static float game_anim_length(const game_state *oldstate,
const game_state *newstate, int dir, game_ui *ui)
{
return 0.0F;
}
static float game_flash_length(const game_state *oldstate,
const game_state *newstate, int dir, game_ui *ui)
{
if (!oldstate->completed && newstate->completed &&
!oldstate->used_solve && !newstate->used_solve)
return FLASH_TIME;
return 0.0F;
}
static void game_get_cursor_location(const game_ui *ui,
const game_drawstate *ds,
const game_state *state,
const game_params *params,
int *x, int *y, int *w, int *h)
{
if(ui->cur_visible) {
*x = COORD(ui->cur_x);
*y = COORD(ui->cur_y);
*w = *h = TILE_SIZE;
}
}
static int game_status(const game_state *state)
{
return state->completed ? +1 : 0;
}
static bool game_timing_state(const game_state *state, game_ui *ui)
{
return true;
}
static void game_print_size(const game_params *params, float *x, float *y)
{
int pw, ph;
/*
* I'll use 6mm squares by default.
*/
game_compute_size(params, 600, &pw, &ph);
*x = pw / 100.0F;
*y = ph / 100.0F;
}
static void game_print(drawing *dr, const game_state *state, int tilesize)
{
int w = state->w, h = state->h;
int ink = print_mono_colour(dr, 0);
int paper = print_mono_colour(dr, 1);
int x, y;
/* Ick: fake up `ds->tilesize' for macro expansion purposes */
game_drawstate ads, *ds = &ads;
game_set_size(dr, ds, NULL, tilesize);
/*
* Border.
*/
print_line_width(dr, TILE_SIZE / 16);
draw_rect_outline(dr, COORD(0), COORD(0),
TILE_SIZE * w, TILE_SIZE * h, ink);
/*
* Grid.
*/
print_line_width(dr, TILE_SIZE / 24);
for (x = 1; x < w; x++)
draw_line(dr, COORD(x), COORD(0), COORD(x), COORD(h), ink);
for (y = 1; y < h; y++)
draw_line(dr, COORD(0), COORD(y), COORD(w), COORD(y), ink);
/*
* Grid contents.
*/
for (y = 0; y < h; y++)
for (x = 0; x < w; x++) {
unsigned int ds_flags = tile_flags(ds, state, NULL, x, y, false);
int dx = COORD(x), dy = COORD(y);
if (ds_flags & DF_BLACK) {
draw_rect(dr, dx, dy, TILE_SIZE, TILE_SIZE, ink);
if (ds_flags & DF_NUMBERED) {
char str[32];
sprintf(str, "%d", GRID(state, lights, x, y));
draw_text(dr, dx + TILE_SIZE/2, dy + TILE_SIZE/2,
FONT_VARIABLE, TILE_SIZE*3/5,
ALIGN_VCENTRE | ALIGN_HCENTRE, paper, str);
}
} else if (ds_flags & DF_LIGHT) {
draw_circle(dr, dx + TILE_SIZE/2, dy + TILE_SIZE/2,
TILE_RADIUS, -1, ink);
}
}
}
#ifdef COMBINED
#define thegame lightup
#endif
const struct game thegame = {
"Light Up", "games.lightup", "lightup",
default_params,
game_fetch_preset, NULL,
decode_params,
encode_params,
free_params,
dup_params,
true, game_configure, custom_params,
validate_params,
new_game_desc,
validate_desc,
new_game,
dup_game,
free_game,
true, solve_game,
true, game_can_format_as_text_now, game_text_format,
new_ui,
free_ui,
encode_ui,
decode_ui,
NULL, /* game_request_keys */
game_changed_state,
interpret_move,
execute_move,
PREFERRED_TILE_SIZE, game_compute_size, game_set_size,
game_colours,
game_new_drawstate,
game_free_drawstate,
game_redraw,
game_anim_length,
game_flash_length,
game_get_cursor_location,
game_status,
true, false, game_print_size, game_print,
false, /* wants_statusbar */
false, game_timing_state,
0, /* flags */
};
#ifdef STANDALONE_SOLVER
int main(int argc, char **argv)
{
game_params *p;
game_state *s;
char *id = NULL, *desc, *result;
const char *err;
int nsol, diff, really_verbose = 0;
unsigned int sflags;
while (--argc > 0) {
char *p = *++argv;
if (!strcmp(p, "-v")) {
really_verbose++;
} else if (*p == '-') {
fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0], p);
return 1;
} else {
id = p;
}
}
if (!id) {
fprintf(stderr, "usage: %s [-v] <game_id>\n", argv[0]);
return 1;
}
desc = strchr(id, ':');
if (!desc) {
fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]);
return 1;
}
*desc++ = '\0';
p = default_params();
decode_params(p, id);
err = validate_desc(p, desc);
if (err) {
fprintf(stderr, "%s: %s\n", argv[0], err);
return 1;
}
s = new_game(NULL, p, desc);
/* Run the solvers easiest to hardest until we find one that
* can solve our puzzle. If it's soluble we know that the
* hardest (recursive) solver will always find the solution. */
nsol = sflags = 0;
for (diff = 0; diff <= DIFFCOUNT; diff++) {
printf("\nSolving with difficulty %d.\n", diff);
sflags = flags_from_difficulty(diff);
unplace_lights(s);
nsol = dosolve(s, sflags, NULL);
if (nsol == 1) break;
}
printf("\n");
if (nsol == 0) {
printf("Puzzle has no solution.\n");
} else if (nsol < 0) {
printf("Unable to find a unique solution.\n");
} else if (nsol > 1) {
printf("Puzzle has multiple solutions.\n");
} else {
verbose = really_verbose;
unplace_lights(s);
printf("Puzzle has difficulty %d: solving...\n", diff);
dosolve(s, sflags, NULL); /* sflags from last successful solve */
result = game_text_format(s);
printf("%s", result);
sfree(result);
}
return 0;
}
#endif
/* vim: set shiftwidth=4 tabstop=8: */