Oops; _actually_ add the reasoning mode I mentioned in the last
[sgt/puzzles] / solo.c
1 /*
2 * solo.c: the number-placing puzzle most popularly known as `Sudoku'.
3 *
4 * TODO:
5 *
6 * - can we do anything about nasty centring of text in GTK? It
7 * seems to be taking ascenders/descenders into account when
8 * centring. Ick.
9 *
10 * - implement stronger modes of reasoning in nsolve, thus
11 * enabling harder puzzles
12 * + and having done that, supply configurable difficulty
13 * levels
14 *
15 * - it might still be nice to do some prioritisation on the
16 * removal of numbers from the grid
17 * + one possibility is to try to minimise the maximum number
18 * of filled squares in any block, which in particular ought
19 * to enforce never leaving a completely filled block in the
20 * puzzle as presented.
21 * + be careful of being too clever here, though, until after
22 * I've tried implementing difficulty levels. It's not
23 * impossible that those might impose much more important
24 * constraints on this process.
25 *
26 * - alternative interface modes
27 * + sudoku.com's Windows program has a palette of possible
28 * entries; you select a palette entry first and then click
29 * on the square you want it to go in, thus enabling
30 * mouse-only play. Useful for PDAs! I don't think it's
31 * actually incompatible with the current highlight-then-type
32 * approach: you _either_ highlight a palette entry and then
33 * click, _or_ you highlight a square and then type. At most
34 * one thing is ever highlighted at a time, so there's no way
35 * to confuse the two.
36 * + `pencil marks' might be useful for more subtle forms of
37 * deduction, once we implement creation of puzzles that
38 * require it.
39 */
40
41 /*
42 * Solo puzzles need to be square overall (since each row and each
43 * column must contain one of every digit), but they need not be
44 * subdivided the same way internally. I am going to adopt a
45 * convention whereby I _always_ refer to `r' as the number of rows
46 * of _big_ divisions, and `c' as the number of columns of _big_
47 * divisions. Thus, a 2c by 3r puzzle looks something like this:
48 *
49 * 4 5 1 | 2 6 3
50 * 6 3 2 | 5 4 1
51 * ------+------ (Of course, you can't subdivide it the other way
52 * 1 4 5 | 6 3 2 or you'll get clashes; observe that the 4 in the
53 * 3 2 6 | 4 1 5 top left would conflict with the 4 in the second
54 * ------+------ box down on the left-hand side.)
55 * 5 1 4 | 3 2 6
56 * 2 6 3 | 1 5 4
57 *
58 * The need for a strong naming convention should now be clear:
59 * each small box is two rows of digits by three columns, while the
60 * overall puzzle has three rows of small boxes by two columns. So
61 * I will (hopefully) consistently use `r' to denote the number of
62 * rows _of small boxes_ (here 3), which is also the number of
63 * columns of digits in each small box; and `c' vice versa (here
64 * 2).
65 *
66 * I'm also going to choose arbitrarily to list c first wherever
67 * possible: the above is a 2x3 puzzle, not a 3x2 one.
68 */
69
70 #include <stdio.h>
71 #include <stdlib.h>
72 #include <string.h>
73 #include <assert.h>
74 #include <ctype.h>
75 #include <math.h>
76
77 #include "puzzles.h"
78
79 /*
80 * To save space, I store digits internally as unsigned char. This
81 * imposes a hard limit of 255 on the order of the puzzle. Since
82 * even a 5x5 takes unacceptably long to generate, I don't see this
83 * as a serious limitation unless something _really_ impressive
84 * happens in computing technology; but here's a typedef anyway for
85 * general good practice.
86 */
87 typedef unsigned char digit;
88 #define ORDER_MAX 255
89
90 #define TILE_SIZE 32
91 #define BORDER 18
92
93 #define FLASH_TIME 0.4F
94
95 enum { SYMM_NONE, SYMM_ROT2, SYMM_ROT4, SYMM_REF4 };
96
97 enum {
98 COL_BACKGROUND,
99 COL_GRID,
100 COL_CLUE,
101 COL_USER,
102 COL_HIGHLIGHT,
103 NCOLOURS
104 };
105
106 struct game_params {
107 int c, r, symm;
108 };
109
110 struct game_state {
111 int c, r;
112 digit *grid;
113 unsigned char *immutable; /* marks which digits are clues */
114 int completed;
115 };
116
117 static game_params *default_params(void)
118 {
119 game_params *ret = snew(game_params);
120
121 ret->c = ret->r = 3;
122 ret->symm = SYMM_ROT2; /* a plausible default */
123
124 return ret;
125 }
126
127 static int game_fetch_preset(int i, char **name, game_params **params)
128 {
129 game_params *ret;
130 int c, r;
131 char buf[80];
132
133 switch (i) {
134 case 0: c = 2, r = 2; break;
135 case 1: c = 2, r = 3; break;
136 case 2: c = 3, r = 3; break;
137 case 3: c = 3, r = 4; break;
138 case 4: c = 4, r = 4; break;
139 default: return FALSE;
140 }
141
142 sprintf(buf, "%dx%d", c, r);
143 *name = dupstr(buf);
144 *params = ret = snew(game_params);
145 ret->c = c;
146 ret->r = r;
147 ret->symm = SYMM_ROT2;
148 /* FIXME: difficulty presets? */
149 return TRUE;
150 }
151
152 static void free_params(game_params *params)
153 {
154 sfree(params);
155 }
156
157 static game_params *dup_params(game_params *params)
158 {
159 game_params *ret = snew(game_params);
160 *ret = *params; /* structure copy */
161 return ret;
162 }
163
164 static game_params *decode_params(char const *string)
165 {
166 game_params *ret = default_params();
167
168 ret->c = ret->r = atoi(string);
169 ret->symm = SYMM_ROT2;
170 while (*string && isdigit((unsigned char)*string)) string++;
171 if (*string == 'x') {
172 string++;
173 ret->r = atoi(string);
174 while (*string && isdigit((unsigned char)*string)) string++;
175 }
176 if (*string == 'r' || *string == 'm' || *string == 'a') {
177 int sn, sc;
178 sc = *string++;
179 sn = atoi(string);
180 while (*string && isdigit((unsigned char)*string)) string++;
181 if (sc == 'm' && sn == 4)
182 ret->symm = SYMM_REF4;
183 if (sc == 'r' && sn == 4)
184 ret->symm = SYMM_ROT4;
185 if (sc == 'r' && sn == 2)
186 ret->symm = SYMM_ROT2;
187 if (sc == 'a')
188 ret->symm = SYMM_NONE;
189 }
190 /* FIXME: difficulty levels */
191
192 return ret;
193 }
194
195 static char *encode_params(game_params *params)
196 {
197 char str[80];
198
199 /*
200 * Symmetry is a game generation preference and hence is left
201 * out of the encoding. Users can add it back in as they see
202 * fit.
203 */
204 sprintf(str, "%dx%d", params->c, params->r);
205 return dupstr(str);
206 }
207
208 static config_item *game_configure(game_params *params)
209 {
210 config_item *ret;
211 char buf[80];
212
213 ret = snewn(5, config_item);
214
215 ret[0].name = "Columns of sub-blocks";
216 ret[0].type = C_STRING;
217 sprintf(buf, "%d", params->c);
218 ret[0].sval = dupstr(buf);
219 ret[0].ival = 0;
220
221 ret[1].name = "Rows of sub-blocks";
222 ret[1].type = C_STRING;
223 sprintf(buf, "%d", params->r);
224 ret[1].sval = dupstr(buf);
225 ret[1].ival = 0;
226
227 ret[2].name = "Symmetry";
228 ret[2].type = C_CHOICES;
229 ret[2].sval = ":None:2-way rotation:4-way rotation:4-way mirror";
230 ret[2].ival = params->symm;
231
232 /*
233 * FIXME: difficulty level.
234 */
235
236 ret[3].name = NULL;
237 ret[3].type = C_END;
238 ret[3].sval = NULL;
239 ret[3].ival = 0;
240
241 return ret;
242 }
243
244 static game_params *custom_params(config_item *cfg)
245 {
246 game_params *ret = snew(game_params);
247
248 ret->c = atoi(cfg[0].sval);
249 ret->r = atoi(cfg[1].sval);
250 ret->symm = cfg[2].ival;
251
252 return ret;
253 }
254
255 static char *validate_params(game_params *params)
256 {
257 if (params->c < 2 || params->r < 2)
258 return "Both dimensions must be at least 2";
259 if (params->c > ORDER_MAX || params->r > ORDER_MAX)
260 return "Dimensions greater than "STR(ORDER_MAX)" are not supported";
261 return NULL;
262 }
263
264 /* ----------------------------------------------------------------------
265 * Full recursive Solo solver.
266 *
267 * The algorithm for this solver is shamelessly copied from a
268 * Python solver written by Andrew Wilkinson (which is GPLed, but
269 * I've reused only ideas and no code). It mostly just does the
270 * obvious recursive thing: pick an empty square, put one of the
271 * possible digits in it, recurse until all squares are filled,
272 * backtrack and change some choices if necessary.
273 *
274 * The clever bit is that every time it chooses which square to
275 * fill in next, it does so by counting the number of _possible_
276 * numbers that can go in each square, and it prioritises so that
277 * it picks a square with the _lowest_ number of possibilities. The
278 * idea is that filling in lots of the obvious bits (particularly
279 * any squares with only one possibility) will cut down on the list
280 * of possibilities for other squares and hence reduce the enormous
281 * search space as much as possible as early as possible.
282 *
283 * In practice the algorithm appeared to work very well; run on
284 * sample problems from the Times it completed in well under a
285 * second on my G5 even when written in Python, and given an empty
286 * grid (so that in principle it would enumerate _all_ solved
287 * grids!) it found the first valid solution just as quickly. So
288 * with a bit more randomisation I see no reason not to use this as
289 * my grid generator.
290 */
291
292 /*
293 * Internal data structure used in solver to keep track of
294 * progress.
295 */
296 struct rsolve_coord { int x, y, r; };
297 struct rsolve_usage {
298 int c, r, cr; /* cr == c*r */
299 /* grid is a copy of the input grid, modified as we go along */
300 digit *grid;
301 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
302 unsigned char *row;
303 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
304 unsigned char *col;
305 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
306 unsigned char *blk;
307 /* This lists all the empty spaces remaining in the grid. */
308 struct rsolve_coord *spaces;
309 int nspaces;
310 /* If we need randomisation in the solve, this is our random state. */
311 random_state *rs;
312 /* Number of solutions so far found, and maximum number we care about. */
313 int solns, maxsolns;
314 };
315
316 /*
317 * The real recursive step in the solving function.
318 */
319 static void rsolve_real(struct rsolve_usage *usage, digit *grid)
320 {
321 int c = usage->c, r = usage->r, cr = usage->cr;
322 int i, j, n, sx, sy, bestm, bestr;
323 int *digits;
324
325 /*
326 * Firstly, check for completion! If there are no spaces left
327 * in the grid, we have a solution.
328 */
329 if (usage->nspaces == 0) {
330 if (!usage->solns) {
331 /*
332 * This is our first solution, so fill in the output grid.
333 */
334 memcpy(grid, usage->grid, cr * cr);
335 }
336 usage->solns++;
337 return;
338 }
339
340 /*
341 * Otherwise, there must be at least one space. Find the most
342 * constrained space, using the `r' field as a tie-breaker.
343 */
344 bestm = cr+1; /* so that any space will beat it */
345 bestr = 0;
346 i = sx = sy = -1;
347 for (j = 0; j < usage->nspaces; j++) {
348 int x = usage->spaces[j].x, y = usage->spaces[j].y;
349 int m;
350
351 /*
352 * Find the number of digits that could go in this space.
353 */
354 m = 0;
355 for (n = 0; n < cr; n++)
356 if (!usage->row[y*cr+n] && !usage->col[x*cr+n] &&
357 !usage->blk[((y/c)*c+(x/r))*cr+n])
358 m++;
359
360 if (m < bestm || (m == bestm && usage->spaces[j].r < bestr)) {
361 bestm = m;
362 bestr = usage->spaces[j].r;
363 sx = x;
364 sy = y;
365 i = j;
366 }
367 }
368
369 /*
370 * Swap that square into the final place in the spaces array,
371 * so that decrementing nspaces will remove it from the list.
372 */
373 if (i != usage->nspaces-1) {
374 struct rsolve_coord t;
375 t = usage->spaces[usage->nspaces-1];
376 usage->spaces[usage->nspaces-1] = usage->spaces[i];
377 usage->spaces[i] = t;
378 }
379
380 /*
381 * Now we've decided which square to start our recursion at,
382 * simply go through all possible values, shuffling them
383 * randomly first if necessary.
384 */
385 digits = snewn(bestm, int);
386 j = 0;
387 for (n = 0; n < cr; n++)
388 if (!usage->row[sy*cr+n] && !usage->col[sx*cr+n] &&
389 !usage->blk[((sy/c)*c+(sx/r))*cr+n]) {
390 digits[j++] = n+1;
391 }
392
393 if (usage->rs) {
394 /* shuffle */
395 for (i = j; i > 1; i--) {
396 int p = random_upto(usage->rs, i);
397 if (p != i-1) {
398 int t = digits[p];
399 digits[p] = digits[i-1];
400 digits[i-1] = t;
401 }
402 }
403 }
404
405 /* And finally, go through the digit list and actually recurse. */
406 for (i = 0; i < j; i++) {
407 n = digits[i];
408
409 /* Update the usage structure to reflect the placing of this digit. */
410 usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] =
411 usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = TRUE;
412 usage->grid[sy*cr+sx] = n;
413 usage->nspaces--;
414
415 /* Call the solver recursively. */
416 rsolve_real(usage, grid);
417
418 /*
419 * If we have seen as many solutions as we need, terminate
420 * all processing immediately.
421 */
422 if (usage->solns >= usage->maxsolns)
423 break;
424
425 /* Revert the usage structure. */
426 usage->row[sy*cr+n-1] = usage->col[sx*cr+n-1] =
427 usage->blk[((sy/c)*c+(sx/r))*cr+n-1] = FALSE;
428 usage->grid[sy*cr+sx] = 0;
429 usage->nspaces++;
430 }
431
432 sfree(digits);
433 }
434
435 /*
436 * Entry point to solver. You give it dimensions and a starting
437 * grid, which is simply an array of N^4 digits. In that array, 0
438 * means an empty square, and 1..N mean a clue square.
439 *
440 * Return value is the number of solutions found; searching will
441 * stop after the provided `max'. (Thus, you can pass max==1 to
442 * indicate that you only care about finding _one_ solution, or
443 * max==2 to indicate that you want to know the difference between
444 * a unique and non-unique solution.) The input parameter `grid' is
445 * also filled in with the _first_ (or only) solution found by the
446 * solver.
447 */
448 static int rsolve(int c, int r, digit *grid, random_state *rs, int max)
449 {
450 struct rsolve_usage *usage;
451 int x, y, cr = c*r;
452 int ret;
453
454 /*
455 * Create an rsolve_usage structure.
456 */
457 usage = snew(struct rsolve_usage);
458
459 usage->c = c;
460 usage->r = r;
461 usage->cr = cr;
462
463 usage->grid = snewn(cr * cr, digit);
464 memcpy(usage->grid, grid, cr * cr);
465
466 usage->row = snewn(cr * cr, unsigned char);
467 usage->col = snewn(cr * cr, unsigned char);
468 usage->blk = snewn(cr * cr, unsigned char);
469 memset(usage->row, FALSE, cr * cr);
470 memset(usage->col, FALSE, cr * cr);
471 memset(usage->blk, FALSE, cr * cr);
472
473 usage->spaces = snewn(cr * cr, struct rsolve_coord);
474 usage->nspaces = 0;
475
476 usage->solns = 0;
477 usage->maxsolns = max;
478
479 usage->rs = rs;
480
481 /*
482 * Now fill it in with data from the input grid.
483 */
484 for (y = 0; y < cr; y++) {
485 for (x = 0; x < cr; x++) {
486 int v = grid[y*cr+x];
487 if (v == 0) {
488 usage->spaces[usage->nspaces].x = x;
489 usage->spaces[usage->nspaces].y = y;
490 if (rs)
491 usage->spaces[usage->nspaces].r = random_bits(rs, 31);
492 else
493 usage->spaces[usage->nspaces].r = usage->nspaces;
494 usage->nspaces++;
495 } else {
496 usage->row[y*cr+v-1] = TRUE;
497 usage->col[x*cr+v-1] = TRUE;
498 usage->blk[((y/c)*c+(x/r))*cr+v-1] = TRUE;
499 }
500 }
501 }
502
503 /*
504 * Run the real recursive solving function.
505 */
506 rsolve_real(usage, grid);
507 ret = usage->solns;
508
509 /*
510 * Clean up the usage structure now we have our answer.
511 */
512 sfree(usage->spaces);
513 sfree(usage->blk);
514 sfree(usage->col);
515 sfree(usage->row);
516 sfree(usage->grid);
517 sfree(usage);
518
519 /*
520 * And return.
521 */
522 return ret;
523 }
524
525 /* ----------------------------------------------------------------------
526 * End of recursive solver code.
527 */
528
529 /* ----------------------------------------------------------------------
530 * Less capable non-recursive solver. This one is used to check
531 * solubility of a grid as we gradually remove numbers from it: by
532 * verifying a grid using this solver we can ensure it isn't _too_
533 * hard (e.g. does not actually require guessing and backtracking).
534 *
535 * It supports a variety of specific modes of reasoning. By
536 * enabling or disabling subsets of these modes we can arrange a
537 * range of difficulty levels.
538 */
539
540 /*
541 * Modes of reasoning currently supported:
542 *
543 * - Positional elimination: a number must go in a particular
544 * square because all the other empty squares in a given
545 * row/col/blk are ruled out.
546 *
547 * - Numeric elimination: a square must have a particular number
548 * in because all the other numbers that could go in it are
549 * ruled out.
550 *
551 * More advanced modes of reasoning I'd like to support in future:
552 *
553 * - Intersectional elimination: given two domains which overlap
554 * (hence one must be a block, and the other can be a row or
555 * col), if the possible locations for a particular number in
556 * one of the domains can be narrowed down to the overlap, then
557 * that number can be ruled out everywhere but the overlap in
558 * the other domain too.
559 *
560 * - Setwise numeric elimination: if there is a subset of the
561 * empty squares within a domain such that the union of the
562 * possible numbers in that subset has the same size as the
563 * subset itself, then those numbers can be ruled out everywhere
564 * else in the domain. (For example, if there are five empty
565 * squares and the possible numbers in each are 12, 23, 13, 134
566 * and 1345, then the first three empty squares form such a
567 * subset: the numbers 1, 2 and 3 _must_ be in those three
568 * squares in some permutation, and hence we can deduce none of
569 * them can be in the fourth or fifth squares.)
570 *
571 * - Setwise positional elimination: if there is a subset of the
572 * unplaced numbers within a domain such that the union of all
573 * their possible positions has the same size as the subset
574 * itself, then all other numbers can be ruled out for those
575 * positions.
576 */
577
578 /*
579 * Within this solver, I'm going to transform all y-coordinates by
580 * inverting the significance of the block number and the position
581 * within the block. That is, we will start with the top row of
582 * each block in order, then the second row of each block in order,
583 * etc.
584 *
585 * This transformation has the enormous advantage that it means
586 * every row, column _and_ block is described by an arithmetic
587 * progression of coordinates within the cubic array, so that I can
588 * use the same very simple function to do blockwise, row-wise and
589 * column-wise elimination.
590 */
591 #define YTRANS(y) (((y)%c)*r+(y)/c)
592 #define YUNTRANS(y) (((y)%r)*c+(y)/r)
593
594 struct nsolve_usage {
595 int c, r, cr;
596 /*
597 * We set up a cubic array, indexed by x, y and digit; each
598 * element of this array is TRUE or FALSE according to whether
599 * or not that digit _could_ in principle go in that position.
600 *
601 * The way to index this array is cube[(x*cr+y)*cr+n-1].
602 * y-coordinates in here are transformed.
603 */
604 unsigned char *cube;
605 /*
606 * This is the grid in which we write down our final
607 * deductions. y-coordinates in here are _not_ transformed.
608 */
609 digit *grid;
610 /*
611 * Now we keep track, at a slightly higher level, of what we
612 * have yet to work out, to prevent doing the same deduction
613 * many times.
614 */
615 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
616 unsigned char *row;
617 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
618 unsigned char *col;
619 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
620 unsigned char *blk;
621 };
622 #define cubepos(x,y,n) (((x)*usage->cr+(y))*usage->cr+(n)-1)
623 #define cube(x,y,n) (usage->cube[cubepos(x,y,n)])
624
625 /*
626 * Function called when we are certain that a particular square has
627 * a particular number in it. The y-coordinate passed in here is
628 * transformed.
629 */
630 static void nsolve_place(struct nsolve_usage *usage, int x, int y, int n)
631 {
632 int c = usage->c, r = usage->r, cr = usage->cr;
633 int i, j, bx, by;
634
635 assert(cube(x,y,n));
636
637 /*
638 * Rule out all other numbers in this square.
639 */
640 for (i = 1; i <= cr; i++)
641 if (i != n)
642 cube(x,y,i) = FALSE;
643
644 /*
645 * Rule out this number in all other positions in the row.
646 */
647 for (i = 0; i < cr; i++)
648 if (i != y)
649 cube(x,i,n) = FALSE;
650
651 /*
652 * Rule out this number in all other positions in the column.
653 */
654 for (i = 0; i < cr; i++)
655 if (i != x)
656 cube(i,y,n) = FALSE;
657
658 /*
659 * Rule out this number in all other positions in the block.
660 */
661 bx = (x/r)*r;
662 by = y % r;
663 for (i = 0; i < r; i++)
664 for (j = 0; j < c; j++)
665 if (bx+i != x || by+j*r != y)
666 cube(bx+i,by+j*r,n) = FALSE;
667
668 /*
669 * Enter the number in the result grid.
670 */
671 usage->grid[YUNTRANS(y)*cr+x] = n;
672
673 /*
674 * Cross out this number from the list of numbers left to place
675 * in its row, its column and its block.
676 */
677 usage->row[y*cr+n-1] = usage->col[x*cr+n-1] =
678 usage->blk[((y/c)*c+(x/r))*cr+n-1] = TRUE;
679 }
680
681 static int nsolve_elim(struct nsolve_usage *usage, int start, int step)
682 {
683 int c = usage->c, r = usage->r, cr = c*r;
684 int fpos, m, i;
685
686 /*
687 * Count the number of set bits within this section of the
688 * cube.
689 */
690 m = 0;
691 fpos = -1;
692 for (i = 0; i < cr; i++)
693 if (usage->cube[start+i*step]) {
694 fpos = start+i*step;
695 m++;
696 }
697
698 if (m == 1) {
699 int x, y, n;
700 assert(fpos >= 0);
701
702 n = 1 + fpos % cr;
703 y = fpos / cr;
704 x = y / cr;
705 y %= cr;
706
707 if (!usage->grid[YUNTRANS(y)*cr+x]) {
708 nsolve_place(usage, x, y, n);
709 return TRUE;
710 }
711 }
712
713 return FALSE;
714 }
715
716 static int nsolve(int c, int r, digit *grid)
717 {
718 struct nsolve_usage *usage;
719 int cr = c*r;
720 int x, y, n;
721
722 /*
723 * Set up a usage structure as a clean slate (everything
724 * possible).
725 */
726 usage = snew(struct nsolve_usage);
727 usage->c = c;
728 usage->r = r;
729 usage->cr = cr;
730 usage->cube = snewn(cr*cr*cr, unsigned char);
731 usage->grid = grid; /* write straight back to the input */
732 memset(usage->cube, TRUE, cr*cr*cr);
733
734 usage->row = snewn(cr * cr, unsigned char);
735 usage->col = snewn(cr * cr, unsigned char);
736 usage->blk = snewn(cr * cr, unsigned char);
737 memset(usage->row, FALSE, cr * cr);
738 memset(usage->col, FALSE, cr * cr);
739 memset(usage->blk, FALSE, cr * cr);
740
741 /*
742 * Place all the clue numbers we are given.
743 */
744 for (x = 0; x < cr; x++)
745 for (y = 0; y < cr; y++)
746 if (grid[y*cr+x])
747 nsolve_place(usage, x, YTRANS(y), grid[y*cr+x]);
748
749 /*
750 * Now loop over the grid repeatedly trying all permitted modes
751 * of reasoning. The loop terminates if we complete an
752 * iteration without making any progress; we then return
753 * failure or success depending on whether the grid is full or
754 * not.
755 */
756 while (1) {
757 cont:
758
759 /*
760 * Blockwise positional elimination.
761 */
762 for (x = 0; x < cr; x += r)
763 for (y = 0; y < r; y++)
764 for (n = 1; n <= cr; n++)
765 if (!usage->blk[(y*c+(x/r))*cr+n-1] &&
766 nsolve_elim(usage, cubepos(x,y,n), r*cr))
767 goto cont;
768
769 /*
770 * Row-wise positional elimination.
771 */
772 for (y = 0; y < cr; y++)
773 for (n = 1; n <= cr; n++)
774 if (!usage->row[y*cr+n-1] &&
775 nsolve_elim(usage, cubepos(0,y,n), cr*cr))
776 goto cont;
777 /*
778 * Column-wise positional elimination.
779 */
780 for (x = 0; x < cr; x++)
781 for (n = 1; n <= cr; n++)
782 if (!usage->col[x*cr+n-1] &&
783 nsolve_elim(usage, cubepos(x,0,n), cr))
784 goto cont;
785
786 /*
787 * Numeric elimination.
788 */
789 for (x = 0; x < cr; x++)
790 for (y = 0; y < cr; y++)
791 if (!usage->grid[YUNTRANS(y)*cr+x] &&
792 nsolve_elim(usage, cubepos(x,y,1), 1))
793 goto cont;
794
795 /*
796 * If we reach here, we have made no deductions in this
797 * iteration, so the algorithm terminates.
798 */
799 break;
800 }
801
802 sfree(usage->cube);
803 sfree(usage->row);
804 sfree(usage->col);
805 sfree(usage->blk);
806 sfree(usage);
807
808 for (x = 0; x < cr; x++)
809 for (y = 0; y < cr; y++)
810 if (!grid[y*cr+x])
811 return FALSE;
812 return TRUE;
813 }
814
815 /* ----------------------------------------------------------------------
816 * End of non-recursive solver code.
817 */
818
819 /*
820 * Check whether a grid contains a valid complete puzzle.
821 */
822 static int check_valid(int c, int r, digit *grid)
823 {
824 int cr = c*r;
825 unsigned char *used;
826 int x, y, n;
827
828 used = snewn(cr, unsigned char);
829
830 /*
831 * Check that each row contains precisely one of everything.
832 */
833 for (y = 0; y < cr; y++) {
834 memset(used, FALSE, cr);
835 for (x = 0; x < cr; x++)
836 if (grid[y*cr+x] > 0 && grid[y*cr+x] <= cr)
837 used[grid[y*cr+x]-1] = TRUE;
838 for (n = 0; n < cr; n++)
839 if (!used[n]) {
840 sfree(used);
841 return FALSE;
842 }
843 }
844
845 /*
846 * Check that each column contains precisely one of everything.
847 */
848 for (x = 0; x < cr; x++) {
849 memset(used, FALSE, cr);
850 for (y = 0; y < cr; y++)
851 if (grid[y*cr+x] > 0 && grid[y*cr+x] <= cr)
852 used[grid[y*cr+x]-1] = TRUE;
853 for (n = 0; n < cr; n++)
854 if (!used[n]) {
855 sfree(used);
856 return FALSE;
857 }
858 }
859
860 /*
861 * Check that each block contains precisely one of everything.
862 */
863 for (x = 0; x < cr; x += r) {
864 for (y = 0; y < cr; y += c) {
865 int xx, yy;
866 memset(used, FALSE, cr);
867 for (xx = x; xx < x+r; xx++)
868 for (yy = 0; yy < y+c; yy++)
869 if (grid[yy*cr+xx] > 0 && grid[yy*cr+xx] <= cr)
870 used[grid[yy*cr+xx]-1] = TRUE;
871 for (n = 0; n < cr; n++)
872 if (!used[n]) {
873 sfree(used);
874 return FALSE;
875 }
876 }
877 }
878
879 sfree(used);
880 return TRUE;
881 }
882
883 static void symmetry_limit(game_params *params, int *xlim, int *ylim, int s)
884 {
885 int c = params->c, r = params->r, cr = c*r;
886
887 switch (s) {
888 case SYMM_NONE:
889 *xlim = *ylim = cr;
890 break;
891 case SYMM_ROT2:
892 *xlim = (cr+1) / 2;
893 *ylim = cr;
894 break;
895 case SYMM_REF4:
896 case SYMM_ROT4:
897 *xlim = *ylim = (cr+1) / 2;
898 break;
899 }
900 }
901
902 static int symmetries(game_params *params, int x, int y, int *output, int s)
903 {
904 int c = params->c, r = params->r, cr = c*r;
905 int i = 0;
906
907 *output++ = x;
908 *output++ = y;
909 i++;
910
911 switch (s) {
912 case SYMM_NONE:
913 break; /* just x,y is all we need */
914 case SYMM_REF4:
915 case SYMM_ROT4:
916 switch (s) {
917 case SYMM_REF4:
918 *output++ = cr - 1 - x;
919 *output++ = y;
920 i++;
921
922 *output++ = x;
923 *output++ = cr - 1 - y;
924 i++;
925 break;
926 case SYMM_ROT4:
927 *output++ = cr - 1 - y;
928 *output++ = x;
929 i++;
930
931 *output++ = y;
932 *output++ = cr - 1 - x;
933 i++;
934 break;
935 }
936 /* fall through */
937 case SYMM_ROT2:
938 *output++ = cr - 1 - x;
939 *output++ = cr - 1 - y;
940 i++;
941 break;
942 }
943
944 return i;
945 }
946
947 static char *new_game_seed(game_params *params, random_state *rs)
948 {
949 int c = params->c, r = params->r, cr = c*r;
950 int area = cr*cr;
951 digit *grid, *grid2;
952 struct xy { int x, y; } *locs;
953 int nlocs;
954 int ret;
955 char *seed;
956 int coords[16], ncoords;
957 int xlim, ylim;
958
959 /*
960 * Start the recursive solver with an empty grid to generate a
961 * random solved state.
962 */
963 grid = snewn(area, digit);
964 memset(grid, 0, area);
965 ret = rsolve(c, r, grid, rs, 1);
966 assert(ret == 1);
967 assert(check_valid(c, r, grid));
968
969 #ifdef DEBUG
970 memcpy(grid,
971 "\x0\x1\x0\x0\x6\x0\x0\x0\x0"
972 "\x5\x0\x0\x7\x0\x4\x0\x2\x0"
973 "\x0\x0\x6\x1\x0\x0\x0\x0\x0"
974 "\x8\x9\x7\x0\x0\x0\x0\x0\x0"
975 "\x0\x0\x3\x0\x4\x0\x9\x0\x0"
976 "\x0\x0\x0\x0\x0\x0\x8\x7\x6"
977 "\x0\x0\x0\x0\x0\x9\x1\x0\x0"
978 "\x0\x3\x0\x6\x0\x5\x0\x0\x7"
979 "\x0\x0\x0\x0\x8\x0\x0\x5\x0"
980 , area);
981
982 {
983 int y, x;
984 for (y = 0; y < cr; y++) {
985 for (x = 0; x < cr; x++) {
986 printf("%2.0d", grid[y*cr+x]);
987 }
988 printf("\n");
989 }
990 printf("\n");
991 }
992
993 nsolve(c, r, grid);
994
995 {
996 int y, x;
997 for (y = 0; y < cr; y++) {
998 for (x = 0; x < cr; x++) {
999 printf("%2.0d", grid[y*cr+x]);
1000 }
1001 printf("\n");
1002 }
1003 printf("\n");
1004 }
1005 #endif
1006
1007 /*
1008 * Now we have a solved grid, start removing things from it
1009 * while preserving solubility.
1010 */
1011 locs = snewn(area, struct xy);
1012 grid2 = snewn(area, digit);
1013 symmetry_limit(params, &xlim, &ylim, params->symm);
1014 while (1) {
1015 int x, y, i, j;
1016
1017 /*
1018 * Iterate over the grid and enumerate all the filled
1019 * squares we could empty.
1020 */
1021 nlocs = 0;
1022
1023 for (x = 0; x < xlim; x++)
1024 for (y = 0; y < ylim; y++)
1025 if (grid[y*cr+x]) {
1026 locs[nlocs].x = x;
1027 locs[nlocs].y = y;
1028 nlocs++;
1029 }
1030
1031 /*
1032 * Now shuffle that list.
1033 */
1034 for (i = nlocs; i > 1; i--) {
1035 int p = random_upto(rs, i);
1036 if (p != i-1) {
1037 struct xy t = locs[p];
1038 locs[p] = locs[i-1];
1039 locs[i-1] = t;
1040 }
1041 }
1042
1043 /*
1044 * Now loop over the shuffled list and, for each element,
1045 * see whether removing that element (and its reflections)
1046 * from the grid will still leave the grid soluble by
1047 * nsolve.
1048 */
1049 for (i = 0; i < nlocs; i++) {
1050 x = locs[i].x;
1051 y = locs[i].y;
1052
1053 memcpy(grid2, grid, area);
1054 ncoords = symmetries(params, x, y, coords, params->symm);
1055 for (j = 0; j < ncoords; j++)
1056 grid2[coords[2*j+1]*cr+coords[2*j]] = 0;
1057
1058 if (nsolve(c, r, grid2)) {
1059 for (j = 0; j < ncoords; j++)
1060 grid[coords[2*j+1]*cr+coords[2*j]] = 0;
1061 break;
1062 }
1063 }
1064
1065 if (i == nlocs) {
1066 /*
1067 * There was nothing we could remove without destroying
1068 * solvability.
1069 */
1070 break;
1071 }
1072 }
1073 sfree(grid2);
1074 sfree(locs);
1075
1076 #ifdef DEBUG
1077 {
1078 int y, x;
1079 for (y = 0; y < cr; y++) {
1080 for (x = 0; x < cr; x++) {
1081 printf("%2.0d", grid[y*cr+x]);
1082 }
1083 printf("\n");
1084 }
1085 printf("\n");
1086 }
1087 #endif
1088
1089 /*
1090 * Now we have the grid as it will be presented to the user.
1091 * Encode it in a game seed.
1092 */
1093 {
1094 char *p;
1095 int run, i;
1096
1097 seed = snewn(5 * area, char);
1098 p = seed;
1099 run = 0;
1100 for (i = 0; i <= area; i++) {
1101 int n = (i < area ? grid[i] : -1);
1102
1103 if (!n)
1104 run++;
1105 else {
1106 if (run) {
1107 while (run > 0) {
1108 int c = 'a' - 1 + run;
1109 if (run > 26)
1110 c = 'z';
1111 *p++ = c;
1112 run -= c - ('a' - 1);
1113 }
1114 } else {
1115 /*
1116 * If there's a number in the very top left or
1117 * bottom right, there's no point putting an
1118 * unnecessary _ before or after it.
1119 */
1120 if (p > seed && n > 0)
1121 *p++ = '_';
1122 }
1123 if (n > 0)
1124 p += sprintf(p, "%d", n);
1125 run = 0;
1126 }
1127 }
1128 assert(p - seed < 5 * area);
1129 *p++ = '\0';
1130 seed = sresize(seed, p - seed, char);
1131 }
1132
1133 sfree(grid);
1134
1135 return seed;
1136 }
1137
1138 static char *validate_seed(game_params *params, char *seed)
1139 {
1140 int area = params->r * params->r * params->c * params->c;
1141 int squares = 0;
1142
1143 while (*seed) {
1144 int n = *seed++;
1145 if (n >= 'a' && n <= 'z') {
1146 squares += n - 'a' + 1;
1147 } else if (n == '_') {
1148 /* do nothing */;
1149 } else if (n > '0' && n <= '9') {
1150 squares++;
1151 while (*seed >= '0' && *seed <= '9')
1152 seed++;
1153 } else
1154 return "Invalid character in game specification";
1155 }
1156
1157 if (squares < area)
1158 return "Not enough data to fill grid";
1159
1160 if (squares > area)
1161 return "Too much data to fit in grid";
1162
1163 return NULL;
1164 }
1165
1166 static game_state *new_game(game_params *params, char *seed)
1167 {
1168 game_state *state = snew(game_state);
1169 int c = params->c, r = params->r, cr = c*r, area = cr * cr;
1170 int i;
1171
1172 state->c = params->c;
1173 state->r = params->r;
1174
1175 state->grid = snewn(area, digit);
1176 state->immutable = snewn(area, unsigned char);
1177 memset(state->immutable, FALSE, area);
1178
1179 state->completed = FALSE;
1180
1181 i = 0;
1182 while (*seed) {
1183 int n = *seed++;
1184 if (n >= 'a' && n <= 'z') {
1185 int run = n - 'a' + 1;
1186 assert(i + run <= area);
1187 while (run-- > 0)
1188 state->grid[i++] = 0;
1189 } else if (n == '_') {
1190 /* do nothing */;
1191 } else if (n > '0' && n <= '9') {
1192 assert(i < area);
1193 state->immutable[i] = TRUE;
1194 state->grid[i++] = atoi(seed-1);
1195 while (*seed >= '0' && *seed <= '9')
1196 seed++;
1197 } else {
1198 assert(!"We can't get here");
1199 }
1200 }
1201 assert(i == area);
1202
1203 return state;
1204 }
1205
1206 static game_state *dup_game(game_state *state)
1207 {
1208 game_state *ret = snew(game_state);
1209 int c = state->c, r = state->r, cr = c*r, area = cr * cr;
1210
1211 ret->c = state->c;
1212 ret->r = state->r;
1213
1214 ret->grid = snewn(area, digit);
1215 memcpy(ret->grid, state->grid, area);
1216
1217 ret->immutable = snewn(area, unsigned char);
1218 memcpy(ret->immutable, state->immutable, area);
1219
1220 ret->completed = state->completed;
1221
1222 return ret;
1223 }
1224
1225 static void free_game(game_state *state)
1226 {
1227 sfree(state->immutable);
1228 sfree(state->grid);
1229 sfree(state);
1230 }
1231
1232 struct game_ui {
1233 /*
1234 * These are the coordinates of the currently highlighted
1235 * square on the grid, or -1,-1 if there isn't one. When there
1236 * is, pressing a valid number or letter key or Space will
1237 * enter that number or letter in the grid.
1238 */
1239 int hx, hy;
1240 };
1241
1242 static game_ui *new_ui(game_state *state)
1243 {
1244 game_ui *ui = snew(game_ui);
1245
1246 ui->hx = ui->hy = -1;
1247
1248 return ui;
1249 }
1250
1251 static void free_ui(game_ui *ui)
1252 {
1253 sfree(ui);
1254 }
1255
1256 static game_state *make_move(game_state *from, game_ui *ui, int x, int y,
1257 int button)
1258 {
1259 int c = from->c, r = from->r, cr = c*r;
1260 int tx, ty;
1261 game_state *ret;
1262
1263 tx = (x - BORDER) / TILE_SIZE;
1264 ty = (y - BORDER) / TILE_SIZE;
1265
1266 if (tx >= 0 && tx < cr && ty >= 0 && ty < cr && button == LEFT_BUTTON) {
1267 if (tx == ui->hx && ty == ui->hy) {
1268 ui->hx = ui->hy = -1;
1269 } else {
1270 ui->hx = tx;
1271 ui->hy = ty;
1272 }
1273 return from; /* UI activity occurred */
1274 }
1275
1276 if (ui->hx != -1 && ui->hy != -1 &&
1277 ((button >= '1' && button <= '9' && button - '0' <= cr) ||
1278 (button >= 'a' && button <= 'z' && button - 'a' + 10 <= cr) ||
1279 (button >= 'A' && button <= 'Z' && button - 'A' + 10 <= cr) ||
1280 button == ' ')) {
1281 int n = button - '0';
1282 if (button >= 'A' && button <= 'Z')
1283 n = button - 'A' + 10;
1284 if (button >= 'a' && button <= 'z')
1285 n = button - 'a' + 10;
1286 if (button == ' ')
1287 n = 0;
1288
1289 if (from->immutable[ui->hy*cr+ui->hx])
1290 return NULL; /* can't overwrite this square */
1291
1292 ret = dup_game(from);
1293 ret->grid[ui->hy*cr+ui->hx] = n;
1294 ui->hx = ui->hy = -1;
1295
1296 /*
1297 * We've made a real change to the grid. Check to see
1298 * if the game has been completed.
1299 */
1300 if (!ret->completed && check_valid(c, r, ret->grid)) {
1301 ret->completed = TRUE;
1302 }
1303
1304 return ret; /* made a valid move */
1305 }
1306
1307 return NULL;
1308 }
1309
1310 /* ----------------------------------------------------------------------
1311 * Drawing routines.
1312 */
1313
1314 struct game_drawstate {
1315 int started;
1316 int c, r, cr;
1317 digit *grid;
1318 unsigned char *hl;
1319 };
1320
1321 #define XSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1322 #define YSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1323
1324 static void game_size(game_params *params, int *x, int *y)
1325 {
1326 int c = params->c, r = params->r, cr = c*r;
1327
1328 *x = XSIZE(cr);
1329 *y = YSIZE(cr);
1330 }
1331
1332 static float *game_colours(frontend *fe, game_state *state, int *ncolours)
1333 {
1334 float *ret = snewn(3 * NCOLOURS, float);
1335
1336 frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
1337
1338 ret[COL_GRID * 3 + 0] = 0.0F;
1339 ret[COL_GRID * 3 + 1] = 0.0F;
1340 ret[COL_GRID * 3 + 2] = 0.0F;
1341
1342 ret[COL_CLUE * 3 + 0] = 0.0F;
1343 ret[COL_CLUE * 3 + 1] = 0.0F;
1344 ret[COL_CLUE * 3 + 2] = 0.0F;
1345
1346 ret[COL_USER * 3 + 0] = 0.0F;
1347 ret[COL_USER * 3 + 1] = 0.6F * ret[COL_BACKGROUND * 3 + 1];
1348 ret[COL_USER * 3 + 2] = 0.0F;
1349
1350 ret[COL_HIGHLIGHT * 3 + 0] = 0.85F * ret[COL_BACKGROUND * 3 + 0];
1351 ret[COL_HIGHLIGHT * 3 + 1] = 0.85F * ret[COL_BACKGROUND * 3 + 1];
1352 ret[COL_HIGHLIGHT * 3 + 2] = 0.85F * ret[COL_BACKGROUND * 3 + 2];
1353
1354 *ncolours = NCOLOURS;
1355 return ret;
1356 }
1357
1358 static game_drawstate *game_new_drawstate(game_state *state)
1359 {
1360 struct game_drawstate *ds = snew(struct game_drawstate);
1361 int c = state->c, r = state->r, cr = c*r;
1362
1363 ds->started = FALSE;
1364 ds->c = c;
1365 ds->r = r;
1366 ds->cr = cr;
1367 ds->grid = snewn(cr*cr, digit);
1368 memset(ds->grid, 0, cr*cr);
1369 ds->hl = snewn(cr*cr, unsigned char);
1370 memset(ds->hl, 0, cr*cr);
1371
1372 return ds;
1373 }
1374
1375 static void game_free_drawstate(game_drawstate *ds)
1376 {
1377 sfree(ds->hl);
1378 sfree(ds->grid);
1379 sfree(ds);
1380 }
1381
1382 static void draw_number(frontend *fe, game_drawstate *ds, game_state *state,
1383 int x, int y, int hl)
1384 {
1385 int c = state->c, r = state->r, cr = c*r;
1386 int tx, ty;
1387 int cx, cy, cw, ch;
1388 char str[2];
1389
1390 if (ds->grid[y*cr+x] == state->grid[y*cr+x] && ds->hl[y*cr+x] == hl)
1391 return; /* no change required */
1392
1393 tx = BORDER + x * TILE_SIZE + 2;
1394 ty = BORDER + y * TILE_SIZE + 2;
1395
1396 cx = tx;
1397 cy = ty;
1398 cw = TILE_SIZE-3;
1399 ch = TILE_SIZE-3;
1400
1401 if (x % r)
1402 cx--, cw++;
1403 if ((x+1) % r)
1404 cw++;
1405 if (y % c)
1406 cy--, ch++;
1407 if ((y+1) % c)
1408 ch++;
1409
1410 clip(fe, cx, cy, cw, ch);
1411
1412 /* background needs erasing? */
1413 if (ds->grid[y*cr+x] || ds->hl[y*cr+x] != hl)
1414 draw_rect(fe, cx, cy, cw, ch, hl ? COL_HIGHLIGHT : COL_BACKGROUND);
1415
1416 /* new number needs drawing? */
1417 if (state->grid[y*cr+x]) {
1418 str[1] = '\0';
1419 str[0] = state->grid[y*cr+x] + '0';
1420 if (str[0] > '9')
1421 str[0] += 'a' - ('9'+1);
1422 draw_text(fe, tx + TILE_SIZE/2, ty + TILE_SIZE/2,
1423 FONT_VARIABLE, TILE_SIZE/2, ALIGN_VCENTRE | ALIGN_HCENTRE,
1424 state->immutable[y*cr+x] ? COL_CLUE : COL_USER, str);
1425 }
1426
1427 unclip(fe);
1428
1429 draw_update(fe, cx, cy, cw, ch);
1430
1431 ds->grid[y*cr+x] = state->grid[y*cr+x];
1432 ds->hl[y*cr+x] = hl;
1433 }
1434
1435 static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
1436 game_state *state, int dir, game_ui *ui,
1437 float animtime, float flashtime)
1438 {
1439 int c = state->c, r = state->r, cr = c*r;
1440 int x, y;
1441
1442 if (!ds->started) {
1443 /*
1444 * The initial contents of the window are not guaranteed
1445 * and can vary with front ends. To be on the safe side,
1446 * all games should start by drawing a big
1447 * background-colour rectangle covering the whole window.
1448 */
1449 draw_rect(fe, 0, 0, XSIZE(cr), YSIZE(cr), COL_BACKGROUND);
1450
1451 /*
1452 * Draw the grid.
1453 */
1454 for (x = 0; x <= cr; x++) {
1455 int thick = (x % r ? 0 : 1);
1456 draw_rect(fe, BORDER + x*TILE_SIZE - thick, BORDER-1,
1457 1+2*thick, cr*TILE_SIZE+3, COL_GRID);
1458 }
1459 for (y = 0; y <= cr; y++) {
1460 int thick = (y % c ? 0 : 1);
1461 draw_rect(fe, BORDER-1, BORDER + y*TILE_SIZE - thick,
1462 cr*TILE_SIZE+3, 1+2*thick, COL_GRID);
1463 }
1464 }
1465
1466 /*
1467 * Draw any numbers which need redrawing.
1468 */
1469 for (x = 0; x < cr; x++) {
1470 for (y = 0; y < cr; y++) {
1471 draw_number(fe, ds, state, x, y,
1472 (x == ui->hx && y == ui->hy) ||
1473 (flashtime > 0 &&
1474 (flashtime <= FLASH_TIME/3 ||
1475 flashtime >= FLASH_TIME*2/3)));
1476 }
1477 }
1478
1479 /*
1480 * Update the _entire_ grid if necessary.
1481 */
1482 if (!ds->started) {
1483 draw_update(fe, 0, 0, XSIZE(cr), YSIZE(cr));
1484 ds->started = TRUE;
1485 }
1486 }
1487
1488 static float game_anim_length(game_state *oldstate, game_state *newstate,
1489 int dir)
1490 {
1491 return 0.0F;
1492 }
1493
1494 static float game_flash_length(game_state *oldstate, game_state *newstate,
1495 int dir)
1496 {
1497 if (!oldstate->completed && newstate->completed)
1498 return FLASH_TIME;
1499 return 0.0F;
1500 }
1501
1502 static int game_wants_statusbar(void)
1503 {
1504 return FALSE;
1505 }
1506
1507 #ifdef COMBINED
1508 #define thegame solo
1509 #endif
1510
1511 const struct game thegame = {
1512 "Solo", "games.solo", TRUE,
1513 default_params,
1514 game_fetch_preset,
1515 decode_params,
1516 encode_params,
1517 free_params,
1518 dup_params,
1519 game_configure,
1520 custom_params,
1521 validate_params,
1522 new_game_seed,
1523 validate_seed,
1524 new_game,
1525 dup_game,
1526 free_game,
1527 new_ui,
1528 free_ui,
1529 make_move,
1530 game_size,
1531 game_colours,
1532 game_new_drawstate,
1533 game_free_drawstate,
1534 game_redraw,
1535 game_anim_length,
1536 game_flash_length,
1537 game_wants_statusbar,
1538 };
1539
1540 #ifdef STANDALONE_SOLVER
1541
1542 void frontend_default_colour(frontend *fe, float *output) {}
1543 void draw_text(frontend *fe, int x, int y, int fonttype, int fontsize,
1544 int align, int colour, char *text) {}
1545 void draw_rect(frontend *fe, int x, int y, int w, int h, int colour) {}
1546 void draw_line(frontend *fe, int x1, int y1, int x2, int y2, int colour) {}
1547 void draw_polygon(frontend *fe, int *coords, int npoints,
1548 int fill, int colour) {}
1549 void clip(frontend *fe, int x, int y, int w, int h) {}
1550 void unclip(frontend *fe) {}
1551 void start_draw(frontend *fe) {}
1552 void draw_update(frontend *fe, int x, int y, int w, int h) {}
1553 void end_draw(frontend *fe) {}
1554
1555 #include <stdarg.h>
1556
1557 void fatal(char *fmt, ...)
1558 {
1559 va_list ap;
1560
1561 fprintf(stderr, "fatal error: ");
1562
1563 va_start(ap, fmt);
1564 vfprintf(stderr, fmt, ap);
1565 va_end(ap);
1566
1567 fprintf(stderr, "\n");
1568 exit(1);
1569 }
1570
1571 int main(int argc, char **argv)
1572 {
1573 game_params *p;
1574 game_state *s;
1575 int recurse = FALSE;
1576 char *id = NULL, *seed, *err;
1577 int y, x;
1578
1579 while (--argc > 0) {
1580 char *p = *++argv;
1581 if (!strcmp(p, "-r")) {
1582 recurse = TRUE;
1583 } else if (!strcmp(p, "-n")) {
1584 recurse = FALSE;
1585 } else if (*p == '-') {
1586 fprintf(stderr, "%s: unrecognised option `%s'\n", argv[0]);
1587 return 1;
1588 } else {
1589 id = p;
1590 }
1591 }
1592
1593 if (!id) {
1594 fprintf(stderr, "usage: %s [-n | -r] <game_id>\n", argv[0]);
1595 return 1;
1596 }
1597
1598 seed = strchr(id, ':');
1599 if (!seed) {
1600 fprintf(stderr, "%s: game id expects a colon in it\n", argv[0]);
1601 return 1;
1602 }
1603 *seed++ = '\0';
1604
1605 p = decode_params(id);
1606 err = validate_seed(p, seed);
1607 if (err) {
1608 fprintf(stderr, "%s: %s\n", argv[0], err);
1609 return 1;
1610 }
1611 s = new_game(p, seed);
1612
1613 if (recurse) {
1614 int ret = rsolve(p->c, p->r, s->grid, NULL, 2);
1615 if (ret > 1) {
1616 printf("multiple solutions detected; only first one output\n");
1617 }
1618 } else {
1619 nsolve(p->c, p->r, s->grid);
1620 }
1621
1622 for (y = 0; y < p->c * p->r; y++) {
1623 for (x = 0; x < p->c * p->r; x++) {
1624 printf("%2.0d", s->grid[y * p->c * p->r + x]);
1625 }
1626 printf("\n");
1627 }
1628 printf("\n");
1629
1630 return 0;
1631 }
1632
1633 #endif