2 * lightup.c: Implementation of the Nikoli game 'Light Up'.
15 * In standalone solver mode, `verbose' is a variable which can be
16 * set by command-line option; in debugging mode it's simply always
19 #if defined STANDALONE_SOLVER
20 #define SOLVER_DIAGNOSTICS
23 #define debug(x) printf x
24 #elif defined SOLVER_DIAGNOSTICS
28 /* --- Constants, structure definitions, etc. --- */
30 #define PREFERRED_TILE_SIZE 32
31 #define TILE_SIZE (ds->tilesize)
32 #define BORDER (TILE_SIZE / 2)
33 #define TILE_RADIUS (ds->crad)
35 #define COORD(x) ( (x) * TILE_SIZE + BORDER )
36 #define FROMCOORD(x) ( ((x) - BORDER + TILE_SIZE) / TILE_SIZE - 1 )
38 #define FLASH_TIME 0.30F
43 COL_BLACK, /* black */
44 COL_LIGHT, /* white */
51 enum { SYMM_NONE, SYMM_REF2, SYMM_ROT2, SYMM_REF4, SYMM_ROT4, SYMM_MAX };
57 int blackpc; /* %age of black squares */
59 int difficulty; /* 0 to DIFFCOUNT */
64 /* flags for black squares */
65 #define F_NUMBERED 2 /* it has a number attached */
66 #define F_NUMBERUSED 4 /* this number was useful for solving */
68 /* flags for non-black squares */
69 #define F_IMPOSSIBLE 8 /* can't put a light here */
76 int *lights; /* For black squares, (optionally) the number
77 of surrounding lights. For non-black squares,
78 the number of times it's lit. size h*w*/
79 unsigned int *flags; /* size h*w */
80 int completed, used_solve;
83 #define GRID(gs,grid,x,y) (gs->grid[(y)*((gs)->w) + (x)])
85 /* A ll_data holds information about which lights would be lit by
86 * a particular grid location's light (or conversely, which locations
87 * could light a specific other location). */
88 /* most things should consider this struct opaque. */
91 int minx, maxx, miny, maxy;
95 /* Macro that executes 'block' once per light in lld, including
96 * the origin if include_origin is specified. 'block' can use
97 * lx and ly as the coords. */
98 #define FOREACHLIT(lld,block) do { \
101 for (lx = (lld)->minx; lx <= (lld)->maxx; lx++) { \
102 if (lx == (lld)->ox) continue; \
106 for (ly = (lld)->miny; ly <= (lld)->maxy; ly++) { \
107 if (!(lld)->include_origin && ly == (lld)->oy) continue; \
114 struct { int x, y; unsigned int f; } points[4];
118 /* Fills in (doesn't allocate) a surrounds structure with the grid locations
119 * around a given square, taking account of the edges. */
120 static void get_surrounds(game_state *state, int ox, int oy, surrounds *s)
122 assert(ox >= 0 && ox < state->w && oy >= 0 && oy < state->h);
124 #define ADDPOINT(cond,nx,ny) do {\
126 s->points[s->npoints].x = (nx); \
127 s->points[s->npoints].y = (ny); \
128 s->points[s->npoints].f = 0; \
131 ADDPOINT(ox > 0, ox-1, oy);
132 ADDPOINT(ox < (state->w-1), ox+1, oy);
133 ADDPOINT(oy > 0, ox, oy-1);
134 ADDPOINT(oy < (state->h-1), ox, oy+1);
137 /* --- Game parameter functions --- */
139 #define DEFAULT_PRESET 0
141 const struct game_params lightup_presets[] = {
142 { 7, 7, 20, SYMM_ROT4, 0 },
143 { 7, 7, 20, SYMM_ROT4, 1 },
144 { 7, 7, 20, SYMM_ROT4, 2 },
145 { 10, 10, 20, SYMM_ROT2, 0 },
146 { 10, 10, 20, SYMM_ROT2, 1 },
148 { 12, 12, 20, SYMM_ROT2, 0 },
149 { 12, 12, 20, SYMM_ROT2, 1 },
151 { 10, 10, 20, SYMM_ROT2, 2 },
152 { 14, 14, 20, SYMM_ROT2, 0 },
153 { 14, 14, 20, SYMM_ROT2, 1 },
154 { 14, 14, 20, SYMM_ROT2, 2 }
158 static game_params *default_params(void)
160 game_params *ret = snew(game_params);
161 *ret = lightup_presets[DEFAULT_PRESET];
166 static int game_fetch_preset(int i, char **name, game_params **params)
171 if (i < 0 || i >= lenof(lightup_presets))
174 ret = default_params();
175 *ret = lightup_presets[i];
178 sprintf(buf, "%dx%d %s",
180 ret->difficulty == 2 ? "hard" :
181 ret->difficulty == 1 ? "tricky" : "easy");
187 static void free_params(game_params *params)
192 static game_params *dup_params(game_params *params)
194 game_params *ret = snew(game_params);
195 *ret = *params; /* structure copy */
199 #define EATNUM(x) do { \
200 (x) = atoi(string); \
201 while (*string && isdigit((unsigned char)*string)) string++; \
204 static void decode_params(game_params *params, char const *string)
207 if (*string == 'x') {
211 if (*string == 'b') {
213 EATNUM(params->blackpc);
215 if (*string == 's') {
217 EATNUM(params->symm);
219 params->difficulty = 0;
220 /* cope with old params */
221 if (*string == 'r') {
222 params->difficulty = 2;
225 if (*string == 'd') {
227 EATNUM(params->difficulty);
231 static char *encode_params(game_params *params, int full)
236 sprintf(buf, "%dx%db%ds%dd%d",
237 params->w, params->h, params->blackpc,
241 sprintf(buf, "%dx%d", params->w, params->h);
246 static config_item *game_configure(game_params *params)
251 ret = snewn(6, config_item);
253 ret[0].name = "Width";
254 ret[0].type = C_STRING;
255 sprintf(buf, "%d", params->w);
256 ret[0].sval = dupstr(buf);
259 ret[1].name = "Height";
260 ret[1].type = C_STRING;
261 sprintf(buf, "%d", params->h);
262 ret[1].sval = dupstr(buf);
265 ret[2].name = "%age of black squares";
266 ret[2].type = C_STRING;
267 sprintf(buf, "%d", params->blackpc);
268 ret[2].sval = dupstr(buf);
271 ret[3].name = "Symmetry";
272 ret[3].type = C_CHOICES;
273 ret[3].sval = ":None"
274 ":2-way mirror:2-way rotational"
275 ":4-way mirror:4-way rotational";
276 ret[3].ival = params->symm;
278 ret[4].name = "Difficulty";
279 ret[4].type = C_CHOICES;
280 ret[4].sval = ":Easy:Tricky:Hard";
281 ret[4].ival = params->difficulty;
291 static game_params *custom_params(config_item *cfg)
293 game_params *ret = snew(game_params);
295 ret->w = atoi(cfg[0].sval);
296 ret->h = atoi(cfg[1].sval);
297 ret->blackpc = atoi(cfg[2].sval);
298 ret->symm = cfg[3].ival;
299 ret->difficulty = cfg[4].ival;
304 static char *validate_params(game_params *params, int full)
306 if (params->w < 2 || params->h < 2)
307 return "Width and height must be at least 2";
309 if (params->blackpc < 5 || params->blackpc > 100)
310 return "Percentage of black squares must be between 5% and 100%";
311 if (params->w != params->h) {
312 if (params->symm == SYMM_ROT4)
313 return "4-fold symmetry is only available with square grids";
315 if (params->symm < 0 || params->symm >= SYMM_MAX)
316 return "Unknown symmetry type";
317 if (params->difficulty < 0 || params->difficulty > DIFFCOUNT)
318 return "Unknown difficulty level";
323 /* --- Game state construction/freeing helper functions --- */
325 static game_state *new_state(game_params *params)
327 game_state *ret = snew(game_state);
331 ret->lights = snewn(ret->w * ret->h, int);
333 memset(ret->lights, 0, ret->w * ret->h * sizeof(int));
334 ret->flags = snewn(ret->w * ret->h, unsigned int);
335 memset(ret->flags, 0, ret->w * ret->h * sizeof(unsigned int));
336 ret->completed = ret->used_solve = 0;
340 static game_state *dup_game(game_state *state)
342 game_state *ret = snew(game_state);
347 ret->lights = snewn(ret->w * ret->h, int);
348 memcpy(ret->lights, state->lights, ret->w * ret->h * sizeof(int));
349 ret->nlights = state->nlights;
351 ret->flags = snewn(ret->w * ret->h, unsigned int);
352 memcpy(ret->flags, state->flags, ret->w * ret->h * sizeof(unsigned int));
354 ret->completed = state->completed;
355 ret->used_solve = state->used_solve;
360 static void free_game(game_state *state)
362 sfree(state->lights);
367 static void debug_state(game_state *state)
372 for (y = 0; y < state->h; y++) {
373 for (x = 0; x < state->w; x++) {
375 if (GRID(state, flags, x, y) & F_BLACK) {
376 if (GRID(state, flags, x, y) & F_NUMBERED)
377 c = GRID(state, lights, x, y) + '0';
381 if (GRID(state, flags, x, y) & F_LIGHT)
383 else if (GRID(state, flags, x, y) & F_IMPOSSIBLE)
386 debug(("%c", (int)c));
389 for (x = 0; x < state->w; x++) {
390 if (GRID(state, flags, x, y) & F_BLACK)
393 c = (GRID(state, flags, x, y) & F_LIGHT) ? 'A' : 'a';
394 c += GRID(state, lights, x, y);
396 debug(("%c", (int)c));
402 /* --- Game completion test routines. --- */
404 /* These are split up because occasionally functions are only
405 * interested in one particular aspect. */
407 /* Returns non-zero if all grid spaces are lit. */
408 static int grid_lit(game_state *state)
412 for (x = 0; x < state->w; x++) {
413 for (y = 0; y < state->h; y++) {
414 if (GRID(state,flags,x,y) & F_BLACK) continue;
415 if (GRID(state,lights,x,y) == 0)
422 /* Returns non-zero if any lights are lit by other lights. */
423 static int grid_overlap(game_state *state)
427 for (x = 0; x < state->w; x++) {
428 for (y = 0; y < state->h; y++) {
429 if (!(GRID(state, flags, x, y) & F_LIGHT)) continue;
430 if (GRID(state, lights, x, y) > 1)
437 static int number_wrong(game_state *state, int x, int y)
440 int i, n, empty, lights = GRID(state, lights, x, y);
443 * This function computes the display hint for a number: we
444 * turn the number red if it is definitely wrong. This means
447 * (a) it has too many lights around it, or
448 * (b) it would have too few lights around it even if all the
449 * plausible squares (not black, lit or F_IMPOSSIBLE) were
450 * filled with lights.
453 assert(GRID(state, flags, x, y) & F_NUMBERED);
454 get_surrounds(state, x, y, &s);
457 for (i = 0; i < s.npoints; i++) {
458 if (GRID(state,flags,s.points[i].x,s.points[i].y) & F_LIGHT) {
462 if (GRID(state,flags,s.points[i].x,s.points[i].y) & F_BLACK)
464 if (GRID(state,flags,s.points[i].x,s.points[i].y) & F_IMPOSSIBLE)
466 if (GRID(state,lights,s.points[i].x,s.points[i].y))
470 return (n > lights || (n + empty < lights));
473 static int number_correct(game_state *state, int x, int y)
476 int n = 0, i, lights = GRID(state, lights, x, y);
478 assert(GRID(state, flags, x, y) & F_NUMBERED);
479 get_surrounds(state, x, y, &s);
480 for (i = 0; i < s.npoints; i++) {
481 if (GRID(state,flags,s.points[i].x,s.points[i].y) & F_LIGHT)
484 return (n == lights) ? 1 : 0;
487 /* Returns non-zero if any numbers add up incorrectly. */
488 static int grid_addsup(game_state *state)
492 for (x = 0; x < state->w; x++) {
493 for (y = 0; y < state->h; y++) {
494 if (!(GRID(state, flags, x, y) & F_NUMBERED)) continue;
495 if (!number_correct(state, x, y)) return 0;
501 static int grid_correct(game_state *state)
503 if (grid_lit(state) &&
504 !grid_overlap(state) &&
505 grid_addsup(state)) return 1;
509 /* --- Board initial setup (blacks, lights, numbers) --- */
511 static void clean_board(game_state *state, int leave_blacks)
514 for (x = 0; x < state->w; x++) {
515 for (y = 0; y < state->h; y++) {
517 GRID(state, flags, x, y) &= F_BLACK;
519 GRID(state, flags, x, y) = 0;
520 GRID(state, lights, x, y) = 0;
526 static void set_blacks(game_state *state, game_params *params, random_state *rs)
528 int x, y, degree = 0, rotate = 0, nblack;
530 int wodd = (state->w % 2) ? 1 : 0;
531 int hodd = (state->h % 2) ? 1 : 0;
534 switch (params->symm) {
535 case SYMM_NONE: degree = 1; rotate = 0; break;
536 case SYMM_ROT2: degree = 2; rotate = 1; break;
537 case SYMM_REF2: degree = 2; rotate = 0; break;
538 case SYMM_ROT4: degree = 4; rotate = 1; break;
539 case SYMM_REF4: degree = 4; rotate = 0; break;
540 default: assert(!"Unknown symmetry type");
542 if (params->symm == SYMM_ROT4 && (state->h != state->w))
543 assert(!"4-fold symmetry unavailable without square grid");
548 if (!rotate) rw += wodd; /* ... but see below. */
550 } else if (degree == 2) {
559 /* clear, then randomise, required region. */
560 clean_board(state, 0);
561 nblack = (rw * rh * params->blackpc) / 100;
562 for (i = 0; i < nblack; i++) {
564 x = random_upto(rs,rw);
565 y = random_upto(rs,rh);
566 } while (GRID(state,flags,x,y) & F_BLACK);
567 GRID(state, flags, x, y) |= F_BLACK;
570 /* Copy required region. */
571 if (params->symm == SYMM_NONE) return;
573 for (x = 0; x < rw; x++) {
574 for (y = 0; y < rh; y++) {
578 xs[1] = state->w - 1 - (rotate ? y : x);
579 ys[1] = rotate ? x : y;
580 xs[2] = rotate ? (state->w - 1 - x) : x;
581 ys[2] = state->h - 1 - y;
582 xs[3] = rotate ? y : (state->w - 1 - x);
583 ys[3] = state->h - 1 - (rotate ? x : y);
587 xs[1] = rotate ? (state->w - 1 - x) : x;
588 ys[1] = state->h - 1 - y;
590 for (i = 1; i < degree; i++) {
591 GRID(state, flags, xs[i], ys[i]) =
592 GRID(state, flags, xs[0], ys[0]);
596 /* SYMM_ROT4 misses the middle square above; fix that here. */
597 if (degree == 4 && rotate && wodd &&
598 (random_upto(rs,100) <= (unsigned int)params->blackpc))
600 state->w/2 + wodd - 1, state->h/2 + hodd - 1) |= F_BLACK;
602 #ifdef SOLVER_DIAGNOSTICS
603 if (verbose) debug_state(state);
607 /* Fills in (does not allocate) a ll_data with all the tiles that would
608 * be illuminated by a light at point (ox,oy). If origin=1 then the
609 * origin is included in this list. */
610 static void list_lights(game_state *state, int ox, int oy, int origin,
615 memset(lld, 0, sizeof(lld));
616 lld->ox = lld->minx = lld->maxx = ox;
617 lld->oy = lld->miny = lld->maxy = oy;
618 lld->include_origin = origin;
621 for (x = ox-1; x >= 0; x--) {
622 if (GRID(state, flags, x, y) & F_BLACK) break;
623 if (x < lld->minx) lld->minx = x;
625 for (x = ox+1; x < state->w; x++) {
626 if (GRID(state, flags, x, y) & F_BLACK) break;
627 if (x > lld->maxx) lld->maxx = x;
631 for (y = oy-1; y >= 0; y--) {
632 if (GRID(state, flags, x, y) & F_BLACK) break;
633 if (y < lld->miny) lld->miny = y;
635 for (y = oy+1; y < state->h; y++) {
636 if (GRID(state, flags, x, y) & F_BLACK) break;
637 if (y > lld->maxy) lld->maxy = y;
641 /* Makes sure a light is the given state, editing the lights table to suit the
642 * new state if necessary. */
643 static void set_light(game_state *state, int ox, int oy, int on)
648 assert(!(GRID(state,flags,ox,oy) & F_BLACK));
650 if (!on && GRID(state,flags,ox,oy) & F_LIGHT) {
652 GRID(state,flags,ox,oy) &= ~F_LIGHT;
654 } else if (on && !(GRID(state,flags,ox,oy) & F_LIGHT)) {
656 GRID(state,flags,ox,oy) |= F_LIGHT;
661 list_lights(state,ox,oy,1,&lld);
662 FOREACHLIT(&lld, GRID(state,lights,lx,ly) += diff; );
666 /* Returns 1 if removing a light at (x,y) would cause a square to go dark. */
667 static int check_dark(game_state *state, int x, int y)
671 list_lights(state, x, y, 1, &lld);
672 FOREACHLIT(&lld, if (GRID(state,lights,lx,ly) == 1) { return 1; } );
676 /* Sets up an initial random correct position (i.e. every
677 * space lit, and no lights lit by other lights) by filling the
678 * grid with lights and then removing lights one by one at random. */
679 static void place_lights(game_state *state, random_state *rs)
681 int i, x, y, n, *numindices, wh = state->w*state->h;
684 numindices = snewn(wh, int);
685 for (i = 0; i < wh; i++) numindices[i] = i;
686 shuffle(numindices, wh, sizeof(*numindices), rs);
688 /* Place a light on all grid squares without lights. */
689 for (x = 0; x < state->w; x++) {
690 for (y = 0; y < state->h; y++) {
691 GRID(state, flags, x, y) &= ~F_MARK; /* we use this later. */
692 if (GRID(state, flags, x, y) & F_BLACK) continue;
693 set_light(state, x, y, 1);
697 for (i = 0; i < wh; i++) {
698 y = numindices[i] / state->w;
699 x = numindices[i] % state->w;
700 if (!(GRID(state, flags, x, y) & F_LIGHT)) continue;
701 if (GRID(state, flags, x, y) & F_MARK) continue;
702 list_lights(state, x, y, 0, &lld);
704 /* If we're not lighting any lights ourself, don't remove anything. */
706 FOREACHLIT(&lld, if (GRID(state,flags,lx,ly) & F_LIGHT) { n += 1; } );
707 if (n == 0) continue; /* [1] */
709 /* Check whether removing lights we're lighting would cause anything
712 FOREACHLIT(&lld, if (GRID(state,flags,lx,ly) & F_LIGHT) { n += check_dark(state,lx,ly); } );
714 /* No, it wouldn't, so we can remove them all. */
715 FOREACHLIT(&lld, set_light(state,lx,ly, 0); );
716 GRID(state,flags,x,y) |= F_MARK;
719 if (!grid_overlap(state)) {
721 return; /* we're done. */
723 assert(grid_lit(state));
725 /* could get here if the line at [1] continue'd out of the loop. */
726 if (grid_overlap(state)) {
728 assert(!"place_lights failed to resolve overlapping lights!");
733 /* Fills in all black squares with numbers of adjacent lights. */
734 static void place_numbers(game_state *state)
739 for (x = 0; x < state->w; x++) {
740 for (y = 0; y < state->h; y++) {
741 if (!(GRID(state,flags,x,y) & F_BLACK)) continue;
742 get_surrounds(state, x, y, &s);
744 for (i = 0; i < s.npoints; i++) {
745 if (GRID(state,flags,s.points[i].x, s.points[i].y) & F_LIGHT)
748 GRID(state,flags,x,y) |= F_NUMBERED;
749 GRID(state,lights,x,y) = n;
754 /* --- Actual solver, with helper subroutines. --- */
756 static void tsl_callback(game_state *state,
757 int lx, int ly, int *x, int *y, int *n)
759 if (GRID(state,flags,lx,ly) & F_IMPOSSIBLE) return;
760 if (GRID(state,lights,lx,ly) > 0) return;
761 *x = lx; *y = ly; (*n)++;
764 static int try_solve_light(game_state *state, int ox, int oy,
765 unsigned int flags, int lights)
768 int sx = 0, sy = 0, n = 0;
770 if (lights > 0) return 0;
771 if (flags & F_BLACK) return 0;
773 /* We have an unlit square; count how many ways there are left to
774 * place a light that lights us (including this square); if only
775 * one, we must put a light there. Squares that could light us
776 * are, of course, the same as the squares we would light... */
777 list_lights(state, ox, oy, 1, &lld);
778 FOREACHLIT(&lld, { tsl_callback(state, lx, ly, &sx, &sy, &n); });
780 set_light(state, sx, sy, 1);
781 #ifdef SOLVER_DIAGNOSTICS
782 debug(("(%d,%d) can only be lit from (%d,%d); setting to LIGHT\n",
784 if (verbose) debug_state(state);
792 static int could_place_light(unsigned int flags, int lights)
794 if (flags & (F_BLACK | F_IMPOSSIBLE)) return 0;
795 return (lights > 0) ? 0 : 1;
798 static int could_place_light_xy(game_state *state, int x, int y)
800 int lights = GRID(state,lights,x,y);
801 unsigned int flags = GRID(state,flags,x,y);
802 return (could_place_light(flags, lights)) ? 1 : 0;
805 /* For a given number square, determine whether we have enough info
806 * to unambiguously place its lights. */
807 static int try_solve_number(game_state *state, int nx, int ny,
808 unsigned int nflags, int nlights)
811 int x, y, nl, ns, i, ret = 0, lights;
814 if (!(nflags & F_NUMBERED)) return 0;
816 get_surrounds(state,nx,ny,&s);
819 /* nl is no. of lights we need to place, ns is no. of spaces we
820 * have to place them in. Try and narrow these down, and mark
821 * points we can ignore later. */
822 for (i = 0; i < s.npoints; i++) {
823 x = s.points[i].x; y = s.points[i].y;
824 flags = GRID(state,flags,x,y);
825 lights = GRID(state,lights,x,y);
826 if (flags & F_LIGHT) {
827 /* light here already; one less light for one less place. */
829 s.points[i].f |= F_MARK;
830 } else if (!could_place_light(flags, lights)) {
832 s.points[i].f |= F_MARK;
835 if (ns == 0) return 0; /* nowhere to put anything. */
837 /* we have placed all lights we need to around here; all remaining
838 * surrounds are therefore IMPOSSIBLE. */
839 GRID(state,flags,nx,ny) |= F_NUMBERUSED;
840 for (i = 0; i < s.npoints; i++) {
841 if (!(s.points[i].f & F_MARK)) {
842 GRID(state,flags,s.points[i].x,s.points[i].y) |= F_IMPOSSIBLE;
846 #ifdef SOLVER_DIAGNOSTICS
847 printf("Clue at (%d,%d) full; setting unlit to IMPOSSIBLE.\n",
849 if (verbose) debug_state(state);
851 } else if (nl == ns) {
852 /* we have as many lights to place as spaces; fill them all. */
853 GRID(state,flags,nx,ny) |= F_NUMBERUSED;
854 for (i = 0; i < s.npoints; i++) {
855 if (!(s.points[i].f & F_MARK)) {
856 set_light(state, s.points[i].x,s.points[i].y, 1);
860 #ifdef SOLVER_DIAGNOSTICS
861 printf("Clue at (%d,%d) trivial; setting unlit to LIGHT.\n",
863 if (verbose) debug_state(state);
874 #define SCRATCHSZ (state->w+state->h)
876 /* New solver algorithm: overlapping sets can add IMPOSSIBLE flags.
877 * Algorithm thanks to Simon:
879 * (a) Any square where you can place a light has a set of squares
880 * which would become non-lights as a result. (This includes
881 * squares lit by the first square, and can also include squares
882 * adjacent to the same clue square if the new light is the last
883 * one around that clue.) Call this MAKESDARK(x,y) with (x,y) being
884 * the square you place a light.
886 * (b) Any unlit square has a set of squares on which you could place
887 * a light to illuminate it. (Possibly including itself, of
888 * course.) This set of squares has the property that _at least
889 * one_ of them must contain a light. Sets of this type also arise
890 * from clue squares. Call this MAKESLIGHT(x,y), again with (x,y)
891 * the square you would place a light.
893 * (c) If there exists (dx,dy) and (lx,ly) such that MAKESDARK(dx,dy) is
894 * a superset of MAKESLIGHT(lx,ly), this implies that placing a light at
895 * (dx,dy) would either leave no remaining way to illuminate a certain
896 * square, or would leave no remaining way to fulfill a certain clue
897 * (at lx,ly). In either case, a light can be ruled out at that position.
899 * So, we construct all possible MAKESLIGHT sets, both from unlit squares
900 * and clue squares, and then we look for plausible MAKESDARK sets that include
901 * our (lx,ly) to see if we can find a (dx,dy) to rule out. By the time we have
902 * constructed the MAKESLIGHT set we don't care about (lx,ly), just the set
905 * Once we have such a set, Simon came up with a Cunning Plan to find
906 * the most sensible MAKESDARK candidate:
908 * (a) for each square S in your set X, find all the squares which _would_
909 * rule it out. That means any square which would light S, plus
910 * any square adjacent to the same clue square as S (provided
911 * that clue square has only one remaining light to be placed).
912 * It's not hard to make this list. Don't do anything with this
913 * data at the moment except _count_ the squares.
915 * (b) Find the square S_min in the original set which has the
916 * _smallest_ number of other squares which would rule it out.
918 * (c) Find all the squares that rule out S_min (it's probably
919 * better to recompute this than to have stored it during step
920 * (a), since the CPU requirement is modest but the storage
921 * cost would get ugly.) For each of these squares, see if it
922 * rules out everything else in the set X. Any which does can
923 * be marked as not-a-light.
927 typedef void (*trl_cb)(game_state *state, int dx, int dy,
928 struct setscratch *scratch, int n, void *ctx);
930 static void try_rule_out(game_state *state, int x, int y,
931 struct setscratch *scratch, int n,
932 trl_cb cb, void *ctx);
934 static void trl_callback_search(game_state *state, int dx, int dy,
935 struct setscratch *scratch, int n, void *ignored)
939 #ifdef SOLVER_DIAGNOSTICS
940 if (verbose) debug(("discount cb: light at (%d,%d)\n", dx, dy));
943 for (i = 0; i < n; i++) {
944 if (dx == scratch[i].x && dy == scratch[i].y) {
951 static void trl_callback_discount(game_state *state, int dx, int dy,
952 struct setscratch *scratch, int n, void *ctx)
954 int *didsth = (int *)ctx;
957 if (GRID(state,flags,dx,dy) & F_IMPOSSIBLE) {
958 #ifdef SOLVER_DIAGNOSTICS
959 debug(("Square at (%d,%d) already impossible.\n", dx,dy));
964 /* Check whether a light at (dx,dy) rules out everything
965 * in scratch, and mark (dx,dy) as IMPOSSIBLE if it does.
966 * We can use try_rule_out for this as well, as the set of
967 * squares which would rule out (x,y) is the same as the
968 * set of squares which (x,y) would rule out. */
970 #ifdef SOLVER_DIAGNOSTICS
971 if (verbose) debug(("Checking whether light at (%d,%d) rules out everything in scratch.\n", dx, dy));
974 for (i = 0; i < n; i++)
976 try_rule_out(state, dx, dy, scratch, n, trl_callback_search, NULL);
977 for (i = 0; i < n; i++) {
978 if (scratch[i].n == 0) return;
980 /* The light ruled out everything in scratch. Yay. */
981 GRID(state,flags,dx,dy) |= F_IMPOSSIBLE;
982 #ifdef SOLVER_DIAGNOSTICS
983 debug(("Set reduction discounted square at (%d,%d):\n", dx,dy));
984 if (verbose) debug_state(state);
990 static void trl_callback_incn(game_state *state, int dx, int dy,
991 struct setscratch *scratch, int n, void *ctx)
993 struct setscratch *s = (struct setscratch *)ctx;
997 static void try_rule_out(game_state *state, int x, int y,
998 struct setscratch *scratch, int n,
999 trl_cb cb, void *ctx)
1001 /* XXX Find all the squares which would rule out (x,y); anything
1002 * that would light it as well as squares adjacent to same clues
1003 * as X assuming that clue only has one remaining light.
1004 * Call the callback with each square. */
1007 int i, j, curr_lights, tot_lights;
1009 /* Find all squares that would rule out a light at (x,y) and call trl_cb
1010 * with them: anything that would light (x,y)... */
1012 list_lights(state, x, y, 0, &lld);
1013 FOREACHLIT(&lld, { if (could_place_light_xy(state, lx, ly)) { cb(state, lx, ly, scratch, n, ctx); } });
1015 /* ... as well as any empty space (that isn't x,y) next to any clue square
1016 * next to (x,y) that only has one light left to place. */
1018 get_surrounds(state, x, y, &s);
1019 for (i = 0; i < s.npoints; i++) {
1020 if (!(GRID(state,flags,s.points[i].x,s.points[i].y) & F_NUMBERED))
1022 /* we have an adjacent clue square; find /its/ surrounds
1023 * and count the remaining lights it needs. */
1024 get_surrounds(state,s.points[i].x,s.points[i].y,&ss);
1026 for (j = 0; j < ss.npoints; j++) {
1027 if (GRID(state,flags,ss.points[j].x,ss.points[j].y) & F_LIGHT)
1030 tot_lights = GRID(state, lights, s.points[i].x, s.points[i].y);
1031 /* We have a clue with tot_lights to fill, and curr_lights currently
1032 * around it. If adding a light at (x,y) fills up the clue (i.e.
1033 * curr_lights + 1 = tot_lights) then we need to discount all other
1034 * unlit squares around the clue. */
1035 if ((curr_lights + 1) == tot_lights) {
1036 for (j = 0; j < ss.npoints; j++) {
1037 int lx = ss.points[j].x, ly = ss.points[j].y;
1038 if (lx == x && ly == y) continue;
1039 if (could_place_light_xy(state, lx, ly))
1040 cb(state, lx, ly, scratch, n, ctx);
1046 #ifdef SOLVER_DIAGNOSTICS
1047 static void debug_scratch(const char *msg, struct setscratch *scratch, int n)
1050 debug(("%s scratch (%d elements):\n", msg, n));
1051 for (i = 0; i < n; i++) {
1052 debug((" (%d,%d) n%d\n", scratch[i].x, scratch[i].y, scratch[i].n));
1057 static int discount_set(game_state *state,
1058 struct setscratch *scratch, int n)
1060 int i, besti, bestn, didsth = 0;
1062 #ifdef SOLVER_DIAGNOSTICS
1063 if (verbose > 1) debug_scratch("discount_set", scratch, n);
1065 if (n == 0) return 0;
1067 for (i = 0; i < n; i++) {
1068 try_rule_out(state, scratch[i].x, scratch[i].y, scratch, n,
1069 trl_callback_incn, (void*)&(scratch[i]));
1071 #ifdef SOLVER_DIAGNOSTICS
1072 if (verbose > 1) debug_scratch("discount_set after count", scratch, n);
1075 besti = -1; bestn = SCRATCHSZ;
1076 for (i = 0; i < n; i++) {
1077 if (scratch[i].n < bestn) {
1078 bestn = scratch[i].n;
1082 #ifdef SOLVER_DIAGNOSTICS
1083 if (verbose > 1) debug(("best square (%d,%d) with n%d.\n",
1084 scratch[besti].x, scratch[besti].y, scratch[besti].n));
1086 try_rule_out(state, scratch[besti].x, scratch[besti].y, scratch, n,
1087 trl_callback_discount, (void*)&didsth);
1088 #ifdef SOLVER_DIAGNOSTICS
1089 if (didsth) debug((" [from square (%d,%d)]\n",
1090 scratch[besti].x, scratch[besti].y));
1096 static void discount_clear(game_state *state, struct setscratch *scratch, int *n)
1099 memset(scratch, 0, SCRATCHSZ * sizeof(struct setscratch));
1102 static void unlit_cb(game_state *state, int lx, int ly,
1103 struct setscratch *scratch, int *n)
1105 if (could_place_light_xy(state, lx, ly)) {
1106 scratch[*n].x = lx; scratch[*n].y = ly; (*n)++;
1110 /* Construct a MAKESLIGHT set from an unlit square. */
1111 static int discount_unlit(game_state *state, int x, int y,
1112 struct setscratch *scratch)
1117 #ifdef SOLVER_DIAGNOSTICS
1118 if (verbose) debug(("Trying to discount for unlit square at (%d,%d).\n", x, y));
1119 if (verbose > 1) debug_state(state);
1122 discount_clear(state, scratch, &n);
1124 list_lights(state, x, y, 1, &lld);
1125 FOREACHLIT(&lld, { unlit_cb(state, lx, ly, scratch, &n); });
1126 didsth = discount_set(state, scratch, n);
1127 #ifdef SOLVER_DIAGNOSTICS
1128 if (didsth) debug((" [from unlit square at (%d,%d)].\n", x, y));
1134 /* Construct a series of MAKESLIGHT sets from a clue square.
1135 * for a clue square with N remaining spaces that must contain M lights, every
1136 * subset of size N-M+1 of those N spaces forms such a set.
1139 static int discount_clue(game_state *state, int x, int y,
1140 struct setscratch *scratch)
1142 int slen, m = GRID(state, lights, x, y), n, i, didsth = 0, lights;
1144 surrounds s, sempty;
1147 if (m == 0) return 0;
1149 #ifdef SOLVER_DIAGNOSTICS
1150 if (verbose) debug(("Trying to discount for sets at clue (%d,%d).\n", x, y));
1151 if (verbose > 1) debug_state(state);
1154 /* m is no. of lights still to place; starts off at the clue value
1155 * and decreases when we find a light already down.
1156 * n is no. of spaces left; starts off at 0 and goes up when we find
1157 * a plausible space. */
1159 get_surrounds(state, x, y, &s);
1160 memset(&sempty, 0, sizeof(surrounds));
1161 for (i = 0; i < s.npoints; i++) {
1162 int lx = s.points[i].x, ly = s.points[i].y;
1163 flags = GRID(state,flags,lx,ly);
1164 lights = GRID(state,lights,lx,ly);
1166 if (flags & F_LIGHT) m--;
1168 if (could_place_light(flags, lights)) {
1169 sempty.points[sempty.npoints].x = lx;
1170 sempty.points[sempty.npoints].y = ly;
1174 n = sempty.npoints; /* sempty is now a surrounds of only blank squares. */
1175 if (n == 0) return 0; /* clue is full already. */
1177 if (m < 0 || m > n) return 0; /* become impossible. */
1179 combi = new_combi(n - m + 1, n);
1180 while (next_combi(combi)) {
1181 discount_clear(state, scratch, &slen);
1182 for (i = 0; i < combi->r; i++) {
1183 scratch[slen].x = sempty.points[combi->a[i]].x;
1184 scratch[slen].y = sempty.points[combi->a[i]].y;
1187 if (discount_set(state, scratch, slen)) didsth = 1;
1190 #ifdef SOLVER_DIAGNOSTICS
1191 if (didsth) debug((" [from clue at (%d,%d)].\n", x, y));
1196 #define F_SOLVE_FORCEUNIQUE 1
1197 #define F_SOLVE_DISCOUNTSETS 2
1198 #define F_SOLVE_ALLOWRECURSE 4
1200 static unsigned int flags_from_difficulty(int difficulty)
1202 unsigned int sflags = F_SOLVE_FORCEUNIQUE;
1203 assert(difficulty <= DIFFCOUNT);
1204 if (difficulty >= 1) sflags |= F_SOLVE_DISCOUNTSETS;
1205 if (difficulty >= 2) sflags |= F_SOLVE_ALLOWRECURSE;
1209 #define MAXRECURSE 5
1211 static int solve_sub(game_state *state,
1212 unsigned int solve_flags, int depth,
1216 int x, y, didstuff, ncanplace, lights;
1217 int bestx, besty, n, bestn, copy_soluble, self_soluble, ret, maxrecurse = 0;
1220 struct setscratch *sscratch = NULL;
1222 #ifdef SOLVER_DIAGNOSTICS
1223 printf("solve_sub: depth = %d\n", depth);
1225 if (maxdepth && *maxdepth < depth) *maxdepth = depth;
1226 if (solve_flags & F_SOLVE_ALLOWRECURSE) maxrecurse = MAXRECURSE;
1229 if (grid_overlap(state)) {
1230 /* Our own solver, from scratch, should never cause this to happen
1231 * (assuming a soluble grid). However, if we're trying to solve
1232 * from a half-completed *incorrect* grid this might occur; we
1233 * just return the 'no solutions' code in this case. */
1237 if (grid_correct(state)) { ret = 1; goto done; }
1241 /* These 2 loops, and the functions they call, are the critical loops
1242 * for timing; any optimisations should look here first. */
1243 for (x = 0; x < state->w; x++) {
1244 for (y = 0; y < state->h; y++) {
1245 flags = GRID(state,flags,x,y);
1246 lights = GRID(state,lights,x,y);
1247 ncanplace += could_place_light(flags, lights);
1249 if (try_solve_light(state, x, y, flags, lights)) didstuff = 1;
1250 if (try_solve_number(state, x, y, flags, lights)) didstuff = 1;
1253 if (didstuff) continue;
1255 /* nowhere to put a light, puzzle is unsoluble. */
1259 if (solve_flags & F_SOLVE_DISCOUNTSETS) {
1260 if (!sscratch) sscratch = snewn(SCRATCHSZ, struct setscratch);
1261 /* Try a more cunning (and more involved) way... more details above. */
1262 for (x = 0; x < state->w; x++) {
1263 for (y = 0; y < state->h; y++) {
1264 flags = GRID(state,flags,x,y);
1265 lights = GRID(state,lights,x,y);
1267 if (!(flags & F_BLACK) && lights == 0) {
1268 if (discount_unlit(state, x, y, sscratch)) {
1270 goto reduction_success;
1272 } else if (flags & F_NUMBERED) {
1273 if (discount_clue(state, x, y, sscratch)) {
1275 goto reduction_success;
1282 if (didstuff) continue;
1284 /* We now have to make a guess; we have places to put lights but
1285 * no definite idea about where they can go. */
1286 if (depth >= maxrecurse) {
1287 /* mustn't delve any deeper. */
1288 ret = -1; goto done;
1290 /* Of all the squares that we could place a light, pick the one
1291 * that would light the most currently unlit squares. */
1292 /* This heuristic was just plucked from the air; there may well be
1293 * a more efficient way of choosing a square to flip to minimise
1296 bestx = besty = -1; /* suyb */
1297 for (x = 0; x < state->w; x++) {
1298 for (y = 0; y < state->h; y++) {
1299 flags = GRID(state,flags,x,y);
1300 lights = GRID(state,lights,x,y);
1301 if (!could_place_light(flags, lights)) continue;
1304 list_lights(state, x, y, 1, &lld);
1305 FOREACHLIT(&lld, { if (GRID(state,lights,lx,ly) == 0) n++; });
1307 bestn = n; bestx = x; besty = y;
1312 assert(bestx >= 0 && besty >= 0);
1314 /* Now we've chosen a plausible (x,y), try to solve it once as 'lit'
1315 * and once as 'impossible'; we need to make one copy to do this. */
1317 scopy = dup_game(state);
1318 #ifdef SOLVER_DIAGNOSTICS
1319 debug(("Recursing #1: trying (%d,%d) as IMPOSSIBLE\n", bestx, besty));
1321 GRID(state,flags,bestx,besty) |= F_IMPOSSIBLE;
1322 self_soluble = solve_sub(state, solve_flags, depth+1, maxdepth);
1324 if (!(solve_flags & F_SOLVE_FORCEUNIQUE) && self_soluble > 0) {
1325 /* we didn't care about finding all solutions, and we just
1326 * found one; return with it immediately. */
1332 #ifdef SOLVER_DIAGNOSTICS
1333 debug(("Recursing #2: trying (%d,%d) as LIGHT\n", bestx, besty));
1335 set_light(scopy, bestx, besty, 1);
1336 copy_soluble = solve_sub(scopy, solve_flags, depth+1, maxdepth);
1338 /* If we wanted a unique solution but we hit our recursion limit
1339 * (on either branch) then we have to assume we didn't find possible
1340 * extra solutions, and return 'not soluble'. */
1341 if ((solve_flags & F_SOLVE_FORCEUNIQUE) &&
1342 ((copy_soluble < 0) || (self_soluble < 0))) {
1344 /* Make sure that whether or not it was self or copy (or both) that
1345 * were soluble, that we return a solved state in self. */
1346 } else if (copy_soluble <= 0) {
1347 /* copy wasn't soluble; keep self state and return that result. */
1349 } else if (self_soluble <= 0) {
1350 /* copy solved and we didn't, so copy in copy's (now solved)
1351 * flags and light state. */
1352 memcpy(state->lights, scopy->lights,
1353 scopy->w * scopy->h * sizeof(int));
1354 memcpy(state->flags, scopy->flags,
1355 scopy->w * scopy->h * sizeof(unsigned int));
1358 ret = copy_soluble + self_soluble;
1364 if (sscratch) sfree(sscratch);
1365 #ifdef SOLVER_DIAGNOSTICS
1367 debug(("solve_sub: depth = %d returning, ran out of recursion.\n",
1370 debug(("solve_sub: depth = %d returning, %d solutions.\n",
1376 /* Fills in the (possibly partially-complete) game_state as far as it can,
1377 * returning the number of possible solutions. If it returns >0 then the
1378 * game_state will be in a solved state, but you won't know which one. */
1379 static int dosolve(game_state *state, int solve_flags, int *maxdepth)
1383 for (x = 0; x < state->w; x++) {
1384 for (y = 0; y < state->h; y++) {
1385 GRID(state,flags,x,y) &= ~F_NUMBERUSED;
1388 nsol = solve_sub(state, solve_flags, 0, maxdepth);
1392 static int strip_unused_nums(game_state *state)
1395 for (x = 0; x < state->w; x++) {
1396 for (y = 0; y < state->h; y++) {
1397 if ((GRID(state,flags,x,y) & F_NUMBERED) &&
1398 !(GRID(state,flags,x,y) & F_NUMBERUSED)) {
1399 GRID(state,flags,x,y) &= ~F_NUMBERED;
1400 GRID(state,lights,x,y) = 0;
1405 debug(("Stripped %d unused numbers.\n", n));
1409 static void unplace_lights(game_state *state)
1412 for (x = 0; x < state->w; x++) {
1413 for (y = 0; y < state->h; y++) {
1414 if (GRID(state,flags,x,y) & F_LIGHT)
1415 set_light(state,x,y,0);
1416 GRID(state,flags,x,y) &= ~F_IMPOSSIBLE;
1417 GRID(state,flags,x,y) &= ~F_NUMBERUSED;
1422 static int puzzle_is_good(game_state *state, int difficulty)
1424 int nsol, mdepth = 0;
1425 unsigned int sflags = flags_from_difficulty(difficulty);
1427 unplace_lights(state);
1429 #ifdef SOLVER_DIAGNOSTICS
1430 debug(("Trying to solve with difficulty %d (0x%x):\n",
1431 difficulty, sflags));
1432 if (verbose) debug_state(state);
1435 nsol = dosolve(state, sflags, &mdepth);
1436 /* if we wanted an easy puzzle, make sure we didn't need recursion. */
1437 if (!(sflags & F_SOLVE_ALLOWRECURSE) && mdepth > 0) {
1438 debug(("Ignoring recursive puzzle.\n"));
1442 debug(("%d solutions found.\n", nsol));
1443 if (nsol <= 0) return 0;
1444 if (nsol > 1) return 0;
1448 /* --- New game creation and user input code. --- */
1450 /* The basic algorithm here is to generate the most complex grid possible
1451 * while honouring two restrictions:
1453 * * we require a unique solution, and
1454 * * either we require solubility with no recursion (!params->recurse)
1455 * * or we require some recursion. (params->recurse).
1457 * The solver helpfully keeps track of the numbers it needed to use to
1458 * get its solution, so we use that to remove an initial set of numbers
1459 * and check we still satsify our requirements (on uniqueness and
1460 * non-recursiveness, if applicable; we don't check explicit recursiveness
1463 * Then we try to remove all numbers in a random order, and see if we
1464 * still satisfy requirements (putting them back if we didn't).
1466 * Removing numbers will always, in general terms, make a puzzle require
1467 * more recursion but it may also mean a puzzle becomes non-unique.
1469 * Once we're done, if we wanted a recursive puzzle but the most difficult
1470 * puzzle we could come up with was non-recursive, we give up and try a new
1473 #define MAX_GRIDGEN_TRIES 20
1475 static char *new_game_desc(game_params *params, random_state *rs,
1476 char **aux, int interactive)
1478 game_state *news = new_state(params), *copys;
1479 int i, j, run, x, y, wh = params->w*params->h, num;
1483 /* Construct a shuffled list of grid positions; we only
1484 * do this once, because if it gets used more than once it'll
1485 * be on a different grid layout. */
1486 numindices = snewn(wh, int);
1487 for (j = 0; j < wh; j++) numindices[j] = j;
1488 shuffle(numindices, wh, sizeof(*numindices), rs);
1491 for (i = 0; i < MAX_GRIDGEN_TRIES; i++) {
1492 set_blacks(news, params, rs); /* also cleans board. */
1494 /* set up lights and then the numbers, and remove the lights */
1495 place_lights(news, rs);
1496 debug(("Generating initial grid.\n"));
1497 place_numbers(news);
1498 if (!puzzle_is_good(news, params->difficulty)) continue;
1500 /* Take a copy, remove numbers we didn't use and check there's
1501 * still a unique solution; if so, use the copy subsequently. */
1502 copys = dup_game(news);
1503 strip_unused_nums(copys);
1504 if (!puzzle_is_good(copys, params->difficulty)) {
1505 debug(("Stripped grid is not good, reverting.\n"));
1512 /* Go through grid removing numbers at random one-by-one and
1513 * trying to solve again; if it ceases to be good put the number back. */
1514 for (j = 0; j < wh; j++) {
1515 y = numindices[j] / params->w;
1516 x = numindices[j] % params->w;
1517 if (!(GRID(news, flags, x, y) & F_NUMBERED)) continue;
1518 num = GRID(news, lights, x, y);
1519 GRID(news, lights, x, y) = 0;
1520 GRID(news, flags, x, y) &= ~F_NUMBERED;
1521 if (!puzzle_is_good(news, params->difficulty)) {
1522 GRID(news, lights, x, y) = num;
1523 GRID(news, flags, x, y) |= F_NUMBERED;
1525 debug(("Removed (%d,%d) still soluble.\n", x, y));
1527 if (params->difficulty > 0) {
1528 /* Was the maximally-difficult puzzle difficult enough?
1529 * Check we can't solve it with a more simplistic solver. */
1530 if (puzzle_is_good(news, params->difficulty-1)) {
1531 debug(("Maximally-hard puzzle still not hard enough, skipping.\n"));
1538 /* Couldn't generate a good puzzle in however many goes. Ramp up the
1539 * %age of black squares (if we didn't already have lots; in which case
1540 * why couldn't we generate a puzzle?) and try again. */
1541 if (params->blackpc < 90) params->blackpc += 5;
1542 debug(("New black layout %d%%.\n", params->blackpc));
1545 /* Game is encoded as a long string one character per square;
1547 * 'B' is a black square with no number
1548 * '0', '1', '2', '3', '4' is a black square with a number. */
1549 ret = snewn((params->w * params->h) + 1, char);
1552 for (y = 0; y < params->h; y++) {
1553 for (x = 0; x < params->w; x++) {
1554 if (GRID(news,flags,x,y) & F_BLACK) {
1556 *p++ = ('a'-1) + run;
1559 if (GRID(news,flags,x,y) & F_NUMBERED)
1560 *p++ = '0' + GRID(news,lights,x,y);
1565 *p++ = ('a'-1) + run;
1573 *p++ = ('a'-1) + run;
1577 assert(p - ret <= params->w * params->h);
1584 static char *validate_desc(game_params *params, char *desc)
1587 for (i = 0; i < params->w*params->h; i++) {
1588 if (*desc >= '0' && *desc <= '4')
1590 else if (*desc == 'B')
1592 else if (*desc >= 'a' && *desc <= 'z')
1593 i += *desc - 'a'; /* and the i++ will add another one */
1595 return "Game description shorter than expected";
1597 return "Game description contained unexpected character";
1600 if (*desc || i > params->w*params->h)
1601 return "Game description longer than expected";
1606 static game_state *new_game(midend *me, game_params *params, char *desc)
1608 game_state *ret = new_state(params);
1612 for (y = 0; y < params->h; y++) {
1613 for (x = 0; x < params->w; x++) {
1619 if (c >= 'a' && c <= 'z')
1629 case '0': case '1': case '2': case '3': case '4':
1630 GRID(ret,flags,x,y) |= F_NUMBERED;
1631 GRID(ret,lights,x,y) = (c - '0');
1635 GRID(ret,flags,x,y) |= F_BLACK;
1643 assert(!"Malformed desc.");
1648 if (*desc) assert(!"Over-long desc.");
1653 static char *solve_game(game_state *state, game_state *currstate,
1654 char *aux, char **error)
1657 char *move = NULL, buf[80];
1658 int movelen, movesize, x, y, len;
1659 unsigned int oldflags, solvedflags, sflags;
1661 /* We don't care here about non-unique puzzles; if the
1662 * user entered one themself then I doubt they care. */
1664 sflags = F_SOLVE_ALLOWRECURSE | F_SOLVE_DISCOUNTSETS;
1666 /* Try and solve from where we are now (for non-unique
1667 * puzzles this may produce a different answer). */
1668 solved = dup_game(currstate);
1669 if (dosolve(solved, sflags, NULL) > 0) goto solved;
1672 /* That didn't work; try solving from the clean puzzle. */
1673 solved = dup_game(state);
1674 if (dosolve(solved, sflags, NULL) > 0) goto solved;
1675 *error = "Puzzle is not self-consistent.";
1680 move = snewn(movesize, char);
1682 move[movelen++] = 'S';
1683 move[movelen] = '\0';
1684 for (x = 0; x < currstate->w; x++) {
1685 for (y = 0; y < currstate->h; y++) {
1687 oldflags = GRID(currstate, flags, x, y);
1688 solvedflags = GRID(solved, flags, x, y);
1689 if ((oldflags & F_LIGHT) != (solvedflags & F_LIGHT))
1690 len = sprintf(buf, ";L%d,%d", x, y);
1691 else if ((oldflags & F_IMPOSSIBLE) != (solvedflags & F_IMPOSSIBLE))
1692 len = sprintf(buf, ";I%d,%d", x, y);
1694 if (movelen + len >= movesize) {
1695 movesize = movelen + len + 256;
1696 move = sresize(move, movesize, char);
1698 strcpy(move + movelen, buf);
1709 static int game_can_format_as_text_now(game_params *params)
1714 /* 'borrowed' from slant.c, mainly. I could have printed it one
1715 * character per cell (like debug_state) but that comes out tiny.
1716 * 'L' is used for 'light here' because 'O' looks too much like '0'
1717 * (black square with no surrounding lights). */
1718 static char *game_text_format(game_state *state)
1720 int w = state->w, h = state->h, W = w+1, H = h+1;
1721 int x, y, len, lights;
1725 len = (h+H) * (w+W+1) + 1;
1726 ret = snewn(len, char);
1729 for (y = 0; y < H; y++) {
1730 for (x = 0; x < W; x++) {
1737 for (x = 0; x < W; x++) {
1740 /* actual interesting bit. */
1741 flags = GRID(state, flags, x, y);
1742 lights = GRID(state, lights, x, y);
1743 if (flags & F_BLACK) {
1744 if (flags & F_NUMBERED)
1745 *p++ = '0' + lights;
1749 if (flags & F_LIGHT)
1751 else if (flags & F_IMPOSSIBLE)
1753 else if (lights > 0)
1765 assert(p - ret == len);
1770 int cur_x, cur_y, cur_visible;
1773 static game_ui *new_ui(game_state *state)
1775 game_ui *ui = snew(game_ui);
1776 ui->cur_x = ui->cur_y = ui->cur_visible = 0;
1780 static void free_ui(game_ui *ui)
1785 static char *encode_ui(game_ui *ui)
1787 /* nothing to encode. */
1791 static void decode_ui(game_ui *ui, char *encoding)
1793 /* nothing to decode. */
1796 static void game_changed_state(game_ui *ui, game_state *oldstate,
1797 game_state *newstate)
1799 if (newstate->completed)
1800 ui->cur_visible = 0;
1803 #define DF_BLACK 1 /* black square */
1804 #define DF_NUMBERED 2 /* black square with number */
1805 #define DF_LIT 4 /* display (white) square lit up */
1806 #define DF_LIGHT 8 /* display light in square */
1807 #define DF_OVERLAP 16 /* display light as overlapped */
1808 #define DF_CURSOR 32 /* display cursor */
1809 #define DF_NUMBERWRONG 64 /* display black numbered square as error. */
1810 #define DF_FLASH 128 /* background flash is on. */
1811 #define DF_IMPOSSIBLE 256 /* display non-light little square */
1813 struct game_drawstate {
1816 unsigned int *flags; /* width * height */
1821 /* Believe it or not, this empty = "" hack is needed to get around a bug in
1822 * the prc-tools gcc when optimisation is turned on; before, it produced:
1823 lightup-sect.c: In function `interpret_move':
1824 lightup-sect.c:1416: internal error--unrecognizable insn:
1825 (insn 582 580 583 (set (reg:SI 134)
1829 static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
1830 int x, int y, int button)
1832 enum { NONE, FLIP_LIGHT, FLIP_IMPOSSIBLE } action = NONE;
1833 int cx = -1, cy = -1;
1835 char buf[80], *nullret = NULL, *empty = "", c;
1837 if (button == LEFT_BUTTON || button == RIGHT_BUTTON) {
1838 if (ui->cur_visible)
1840 ui->cur_visible = 0;
1843 action = (button == LEFT_BUTTON) ? FLIP_LIGHT : FLIP_IMPOSSIBLE;
1844 } else if (IS_CURSOR_SELECT(button) ||
1845 button == 'i' || button == 'I' ||
1846 button == ' ' || button == '\r' || button == '\n') {
1847 if (ui->cur_visible) {
1848 /* Only allow cursor-effect operations if the cursor is visible
1849 * (otherwise you have no idea which square it might be affecting) */
1852 action = (button == 'i' || button == 'I' || button == CURSOR_SELECT2) ?
1853 FLIP_IMPOSSIBLE : FLIP_LIGHT;
1855 ui->cur_visible = 1;
1856 } else if (IS_CURSOR_MOVE(button)) {
1857 move_cursor(button, &ui->cur_x, &ui->cur_y, state->w, state->h, 0);
1858 ui->cur_visible = 1;
1865 case FLIP_IMPOSSIBLE:
1866 if (cx < 0 || cy < 0 || cx >= state->w || cy >= state->h)
1868 flags = GRID(state, flags, cx, cy);
1869 if (flags & F_BLACK)
1871 if (action == FLIP_LIGHT) {
1873 if (flags & F_IMPOSSIBLE || flags & F_LIGHT) c = 'I'; else c = 'L';
1875 if (flags & F_IMPOSSIBLE) return nullret;
1880 if (flags & F_IMPOSSIBLE || flags & F_LIGHT) c = 'L'; else c = 'I';
1882 if (flags & F_LIGHT) return nullret;
1886 sprintf(buf, "%c%d,%d", (int)c, cx, cy);
1893 assert(!"Shouldn't get here!");
1898 static game_state *execute_move(game_state *state, char *move)
1900 game_state *ret = dup_game(state);
1904 if (!*move) goto badmove;
1909 ret->used_solve = TRUE;
1911 } else if (c == 'L' || c == 'I') {
1913 if (sscanf(move, "%d,%d%n", &x, &y, &n) != 2 ||
1914 x < 0 || y < 0 || x >= ret->w || y >= ret->h)
1917 flags = GRID(ret, flags, x, y);
1918 if (flags & F_BLACK) goto badmove;
1920 /* LIGHT and IMPOSSIBLE are mutually exclusive. */
1922 GRID(ret, flags, x, y) &= ~F_IMPOSSIBLE;
1923 set_light(ret, x, y, (flags & F_LIGHT) ? 0 : 1);
1925 set_light(ret, x, y, 0);
1926 GRID(ret, flags, x, y) ^= F_IMPOSSIBLE;
1929 } else goto badmove;
1933 else if (*move) goto badmove;
1935 if (grid_correct(ret)) ret->completed = 1;
1943 /* ----------------------------------------------------------------------
1947 /* XXX entirely cloned from fifteen.c; separate out? */
1948 static void game_compute_size(game_params *params, int tilesize,
1951 /* Ick: fake up `ds->tilesize' for macro expansion purposes */
1952 struct { int tilesize; } ads, *ds = &ads;
1953 ads.tilesize = tilesize;
1955 *x = TILE_SIZE * params->w + 2 * BORDER;
1956 *y = TILE_SIZE * params->h + 2 * BORDER;
1959 static void game_set_size(drawing *dr, game_drawstate *ds,
1960 game_params *params, int tilesize)
1962 ds->tilesize = tilesize;
1963 ds->crad = 3*(tilesize-1)/8;
1966 static float *game_colours(frontend *fe, int *ncolours)
1968 float *ret = snewn(3 * NCOLOURS, float);
1971 frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
1973 for (i = 0; i < 3; i++) {
1974 ret[COL_BLACK * 3 + i] = 0.0F;
1975 ret[COL_LIGHT * 3 + i] = 1.0F;
1976 ret[COL_CURSOR * 3 + i] = ret[COL_BACKGROUND * 3 + i] / 2.0F;
1977 ret[COL_GRID * 3 + i] = ret[COL_BACKGROUND * 3 + i] / 1.5F;
1981 ret[COL_ERROR * 3 + 0] = 1.0F;
1982 ret[COL_ERROR * 3 + 1] = 0.25F;
1983 ret[COL_ERROR * 3 + 2] = 0.25F;
1985 ret[COL_LIT * 3 + 0] = 1.0F;
1986 ret[COL_LIT * 3 + 1] = 1.0F;
1987 ret[COL_LIT * 3 + 2] = 0.0F;
1989 *ncolours = NCOLOURS;
1993 static game_drawstate *game_new_drawstate(drawing *dr, game_state *state)
1995 struct game_drawstate *ds = snew(struct game_drawstate);
1998 ds->tilesize = ds->crad = 0;
1999 ds->w = state->w; ds->h = state->h;
2001 ds->flags = snewn(ds->w*ds->h, unsigned int);
2002 for (i = 0; i < ds->w*ds->h; i++)
2010 static void game_free_drawstate(drawing *dr, game_drawstate *ds)
2016 /* At some stage we should put these into a real options struct.
2017 * Note that tile_redraw has no #ifdeffery; it relies on tile_flags not
2018 * to put those flags in. */
2020 #define HINT_OVERLAPS
2021 #define HINT_NUMBERS
2023 static unsigned int tile_flags(game_drawstate *ds, game_state *state, game_ui *ui,
2024 int x, int y, int flashing)
2026 unsigned int flags = GRID(state, flags, x, y);
2027 int lights = GRID(state, lights, x, y);
2028 unsigned int ret = 0;
2030 if (flashing) ret |= DF_FLASH;
2031 if (ui && ui->cur_visible && x == ui->cur_x && y == ui->cur_y)
2034 if (flags & F_BLACK) {
2036 if (flags & F_NUMBERED) {
2038 if (number_wrong(state, x, y))
2039 ret |= DF_NUMBERWRONG;
2045 if (lights > 0) ret |= DF_LIT;
2047 if (flags & F_LIGHT) {
2049 #ifdef HINT_OVERLAPS
2050 if (lights > 1) ret |= DF_OVERLAP;
2053 if (flags & F_IMPOSSIBLE) ret |= DF_IMPOSSIBLE;
2058 static void tile_redraw(drawing *dr, game_drawstate *ds, game_state *state,
2061 unsigned int ds_flags = GRID(ds, flags, x, y);
2062 int dx = COORD(x), dy = COORD(y);
2063 int lit = (ds_flags & DF_FLASH) ? COL_GRID : COL_LIT;
2065 if (ds_flags & DF_BLACK) {
2066 draw_rect(dr, dx, dy, TILE_SIZE, TILE_SIZE, COL_BLACK);
2067 if (ds_flags & DF_NUMBERED) {
2068 int ccol = (ds_flags & DF_NUMBERWRONG) ? COL_ERROR : COL_LIGHT;
2071 /* We know that this won't change over the course of the game
2072 * so it's OK to ignore this when calculating whether or not
2073 * to redraw the tile. */
2074 sprintf(str, "%d", GRID(state, lights, x, y));
2075 draw_text(dr, dx + TILE_SIZE/2, dy + TILE_SIZE/2,
2076 FONT_VARIABLE, TILE_SIZE*3/5,
2077 ALIGN_VCENTRE | ALIGN_HCENTRE, ccol, str);
2080 draw_rect(dr, dx, dy, TILE_SIZE, TILE_SIZE,
2081 (ds_flags & DF_LIT) ? lit : COL_BACKGROUND);
2082 draw_rect_outline(dr, dx, dy, TILE_SIZE, TILE_SIZE, COL_GRID);
2083 if (ds_flags & DF_LIGHT) {
2084 int lcol = (ds_flags & DF_OVERLAP) ? COL_ERROR : COL_LIGHT;
2085 draw_circle(dr, dx + TILE_SIZE/2, dy + TILE_SIZE/2, TILE_RADIUS,
2087 } else if ((ds_flags & DF_IMPOSSIBLE)) {
2088 static int draw_blobs_when_lit = -1;
2089 if (draw_blobs_when_lit < 0) {
2090 char *env = getenv("LIGHTUP_LIT_BLOBS");
2091 draw_blobs_when_lit = (!env || (env[0] == 'y' ||
2094 if (!(ds_flags & DF_LIT) || draw_blobs_when_lit) {
2095 int rlen = TILE_SIZE / 4;
2096 draw_rect(dr, dx + TILE_SIZE/2 - rlen/2,
2097 dy + TILE_SIZE/2 - rlen/2,
2098 rlen, rlen, COL_BLACK);
2103 if (ds_flags & DF_CURSOR) {
2104 int coff = TILE_SIZE/8;
2105 draw_rect_outline(dr, dx + coff, dy + coff,
2106 TILE_SIZE - coff*2, TILE_SIZE - coff*2, COL_CURSOR);
2109 draw_update(dr, dx, dy, TILE_SIZE, TILE_SIZE);
2112 static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
2113 game_state *state, int dir, game_ui *ui,
2114 float animtime, float flashtime)
2116 int flashing = FALSE;
2119 if (flashtime) flashing = (int)(flashtime * 3 / FLASH_TIME) != 1;
2123 TILE_SIZE * ds->w + 2 * BORDER,
2124 TILE_SIZE * ds->h + 2 * BORDER, COL_BACKGROUND);
2126 draw_rect_outline(dr, COORD(0)-1, COORD(0)-1,
2127 TILE_SIZE * ds->w + 2,
2128 TILE_SIZE * ds->h + 2,
2131 draw_update(dr, 0, 0,
2132 TILE_SIZE * ds->w + 2 * BORDER,
2133 TILE_SIZE * ds->h + 2 * BORDER);
2137 for (x = 0; x < ds->w; x++) {
2138 for (y = 0; y < ds->h; y++) {
2139 unsigned int ds_flags = tile_flags(ds, state, ui, x, y, flashing);
2140 if (ds_flags != GRID(ds, flags, x, y)) {
2141 GRID(ds, flags, x, y) = ds_flags;
2142 tile_redraw(dr, ds, state, x, y);
2148 static float game_anim_length(game_state *oldstate, game_state *newstate,
2149 int dir, game_ui *ui)
2154 static float game_flash_length(game_state *oldstate, game_state *newstate,
2155 int dir, game_ui *ui)
2157 if (!oldstate->completed && newstate->completed &&
2158 !oldstate->used_solve && !newstate->used_solve)
2163 static int game_status(game_state *state)
2165 return state->completed ? +1 : 0;
2168 static int game_timing_state(game_state *state, game_ui *ui)
2173 static void game_print_size(game_params *params, float *x, float *y)
2178 * I'll use 6mm squares by default.
2180 game_compute_size(params, 600, &pw, &ph);
2185 static void game_print(drawing *dr, game_state *state, int tilesize)
2187 int w = state->w, h = state->h;
2188 int ink = print_mono_colour(dr, 0);
2189 int paper = print_mono_colour(dr, 1);
2192 /* Ick: fake up `ds->tilesize' for macro expansion purposes */
2193 game_drawstate ads, *ds = &ads;
2194 game_set_size(dr, ds, NULL, tilesize);
2199 print_line_width(dr, TILE_SIZE / 16);
2200 draw_rect_outline(dr, COORD(0), COORD(0),
2201 TILE_SIZE * w, TILE_SIZE * h, ink);
2206 print_line_width(dr, TILE_SIZE / 24);
2207 for (x = 1; x < w; x++)
2208 draw_line(dr, COORD(x), COORD(0), COORD(x), COORD(h), ink);
2209 for (y = 1; y < h; y++)
2210 draw_line(dr, COORD(0), COORD(y), COORD(w), COORD(y), ink);
2215 for (y = 0; y < h; y++)
2216 for (x = 0; x < w; x++) {
2217 unsigned int ds_flags = tile_flags(ds, state, NULL, x, y, FALSE);
2218 int dx = COORD(x), dy = COORD(y);
2219 if (ds_flags & DF_BLACK) {
2220 draw_rect(dr, dx, dy, TILE_SIZE, TILE_SIZE, ink);
2221 if (ds_flags & DF_NUMBERED) {
2223 sprintf(str, "%d", GRID(state, lights, x, y));
2224 draw_text(dr, dx + TILE_SIZE/2, dy + TILE_SIZE/2,
2225 FONT_VARIABLE, TILE_SIZE*3/5,
2226 ALIGN_VCENTRE | ALIGN_HCENTRE, paper, str);
2228 } else if (ds_flags & DF_LIGHT) {
2229 draw_circle(dr, dx + TILE_SIZE/2, dy + TILE_SIZE/2,
2230 TILE_RADIUS, -1, ink);
2236 #define thegame lightup
2239 const struct game thegame = {
2240 "Light Up", "games.lightup", "lightup",
2247 TRUE, game_configure, custom_params,
2255 TRUE, game_can_format_as_text_now, game_text_format,
2263 PREFERRED_TILE_SIZE, game_compute_size, game_set_size,
2266 game_free_drawstate,
2271 TRUE, FALSE, game_print_size, game_print,
2272 FALSE, /* wants_statusbar */
2273 FALSE, game_timing_state,
2277 #ifdef STANDALONE_SOLVER
2279 int main(int argc, char **argv)
2283 char *id = NULL, *desc, *err, *result;
2284 int nsol, diff, really_verbose = 0;
2285 unsigned int sflags;
2287 while (--argc > 0) {
2289 if (!strcmp(p, "-v")) {
2291 } else if (*p == '-') {
2292 fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0], p);
2300 fprintf(stderr, "usage: %s [-v] <game_id>\n", argv[0]);
2304 desc = strchr(id, ':');
2306 fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]);
2311 p = default_params();
2312 decode_params(p, id);
2313 err = validate_desc(p, desc);
2315 fprintf(stderr, "%s: %s\n", argv[0], err);
2318 s = new_game(NULL, p, desc);
2320 /* Run the solvers easiest to hardest until we find one that
2321 * can solve our puzzle. If it's soluble we know that the
2322 * hardest (recursive) solver will always find the solution. */
2324 for (diff = 0; diff <= DIFFCOUNT; diff++) {
2325 printf("\nSolving with difficulty %d.\n", diff);
2326 sflags = flags_from_difficulty(diff);
2328 nsol = dosolve(s, sflags, NULL);
2329 if (nsol == 1) break;
2334 printf("Puzzle has no solution.\n");
2335 } else if (nsol < 0) {
2336 printf("Unable to find a unique solution.\n");
2337 } else if (nsol > 1) {
2338 printf("Puzzle has multiple solutions.\n");
2340 verbose = really_verbose;
2342 printf("Puzzle has difficulty %d: solving...\n", diff);
2343 dosolve(s, sflags, NULL); /* sflags from last successful solve */
2344 result = game_text_format(s);
2345 printf("%s", result);
2354 /* vim: set shiftwidth=4 tabstop=8: */