2 * solo.c: the number-placing puzzle most popularly known as `Sudoku'.
6 * - can we do anything about nasty centring of text in GTK? It
7 * seems to be taking ascenders/descenders into account when
10 * - implement stronger modes of reasoning in nsolve, thus
11 * enabling harder puzzles
12 * + and having done that, supply configurable difficulty
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.
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
36 * + `pencil marks' might be useful for more subtle forms of
37 * deduction, once we implement creation of puzzles that
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:
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.)
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
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.
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.
87 typedef unsigned char digit
;
93 #define FLASH_TIME 0.4F
95 enum { SYMM_NONE
, SYMM_ROT2
, SYMM_ROT4
, SYMM_REF4
};
113 unsigned char *immutable
; /* marks which digits are clues */
117 static game_params
*default_params(void)
119 game_params
*ret
= snew(game_params
);
122 ret
->symm
= SYMM_ROT2
; /* a plausible default */
127 static int game_fetch_preset(int i
, char **name
, game_params
**params
)
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
;
142 sprintf(buf
, "%dx%d", c
, r
);
144 *params
= ret
= snew(game_params
);
147 ret
->symm
= SYMM_ROT2
;
148 /* FIXME: difficulty presets? */
152 static void free_params(game_params
*params
)
157 static game_params
*dup_params(game_params
*params
)
159 game_params
*ret
= snew(game_params
);
160 *ret
= *params
; /* structure copy */
164 static game_params
*decode_params(char const *string
)
166 game_params
*ret
= default_params();
168 ret
->c
= ret
->r
= atoi(string
);
169 ret
->symm
= SYMM_ROT2
;
170 while (*string
&& isdigit((unsigned char)*string
)) string
++;
171 if (*string
== 'x') {
173 ret
->r
= atoi(string
);
174 while (*string
&& isdigit((unsigned char)*string
)) string
++;
176 if (*string
== 'r' || *string
== 'm' || *string
== 'a') {
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
;
188 ret
->symm
= SYMM_NONE
;
190 /* FIXME: difficulty levels */
195 static char *encode_params(game_params
*params
)
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
204 sprintf(str
, "%dx%d", params
->c
, params
->r
);
208 static config_item
*game_configure(game_params
*params
)
213 ret
= snewn(5, config_item
);
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
);
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
);
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
;
233 * FIXME: difficulty level.
244 static game_params
*custom_params(config_item
*cfg
)
246 game_params
*ret
= snew(game_params
);
248 ret
->c
= atoi(cfg
[0].sval
);
249 ret
->r
= atoi(cfg
[1].sval
);
250 ret
->symm
= cfg
[2].ival
;
255 static char *validate_params(game_params
*params
)
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";
264 /* ----------------------------------------------------------------------
265 * Full recursive Solo solver.
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.
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.
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
293 * Internal data structure used in solver to keep track of
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 */
301 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
303 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
305 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
307 /* This lists all the empty spaces remaining in the grid. */
308 struct rsolve_coord
*spaces
;
310 /* If we need randomisation in the solve, this is our random state. */
312 /* Number of solutions so far found, and maximum number we care about. */
317 * The real recursive step in the solving function.
319 static void rsolve_real(struct rsolve_usage
*usage
, digit
*grid
)
321 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
322 int i
, j
, n
, sx
, sy
, bestm
, bestr
;
326 * Firstly, check for completion! If there are no spaces left
327 * in the grid, we have a solution.
329 if (usage
->nspaces
== 0) {
332 * This is our first solution, so fill in the output grid.
334 memcpy(grid
, usage
->grid
, cr
* cr
);
341 * Otherwise, there must be at least one space. Find the most
342 * constrained space, using the `r' field as a tie-breaker.
344 bestm
= cr
+1; /* so that any space will beat it */
347 for (j
= 0; j
< usage
->nspaces
; j
++) {
348 int x
= usage
->spaces
[j
].x
, y
= usage
->spaces
[j
].y
;
352 * Find the number of digits that could go in this space.
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
])
360 if (m
< bestm
|| (m
== bestm
&& usage
->spaces
[j
].r
< bestr
)) {
362 bestr
= usage
->spaces
[j
].r
;
370 * Swap that square into the final place in the spaces array,
371 * so that decrementing nspaces will remove it from the list.
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
;
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.
385 digits
= snewn(bestm
, int);
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
]) {
395 for (i
= j
; i
> 1; i
--) {
396 int p
= random_upto(usage
->rs
, i
);
399 digits
[p
] = digits
[i
-1];
405 /* And finally, go through the digit list and actually recurse. */
406 for (i
= 0; i
< j
; i
++) {
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
;
415 /* Call the solver recursively. */
416 rsolve_real(usage
, grid
);
419 * If we have seen as many solutions as we need, terminate
420 * all processing immediately.
422 if (usage
->solns
>= usage
->maxsolns
)
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;
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.
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
448 static int rsolve(int c
, int r
, digit
*grid
, random_state
*rs
, int max
)
450 struct rsolve_usage
*usage
;
455 * Create an rsolve_usage structure.
457 usage
= snew(struct rsolve_usage
);
463 usage
->grid
= snewn(cr
* cr
, digit
);
464 memcpy(usage
->grid
, grid
, cr
* cr
);
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
);
473 usage
->spaces
= snewn(cr
* cr
, struct rsolve_coord
);
477 usage
->maxsolns
= max
;
482 * Now fill it in with data from the input grid.
484 for (y
= 0; y
< cr
; y
++) {
485 for (x
= 0; x
< cr
; x
++) {
486 int v
= grid
[y
*cr
+x
];
488 usage
->spaces
[usage
->nspaces
].x
= x
;
489 usage
->spaces
[usage
->nspaces
].y
= y
;
491 usage
->spaces
[usage
->nspaces
].r
= random_bits(rs
, 31);
493 usage
->spaces
[usage
->nspaces
].r
= usage
->nspaces
;
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
;
504 * Run the real recursive solving function.
506 rsolve_real(usage
, grid
);
510 * Clean up the usage structure now we have our answer.
512 sfree(usage
->spaces
);
525 /* ----------------------------------------------------------------------
526 * End of recursive solver code.
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).
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.
541 * Modes of reasoning currently supported:
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.
547 * - Numeric elimination: a square must have a particular number
548 * in because all the other numbers that could go in it are
551 * More advanced modes of reasoning I'd like to support in future:
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.
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.)
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
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,
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.
591 #define YTRANS(y) (((y)%c)*r+(y)/c)
592 #define YUNTRANS(y) (((y)%r)*c+(y)/r)
594 struct nsolve_usage
{
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.
601 * The way to index this array is cube[(x*cr+y)*cr+n-1].
602 * y-coordinates in here are transformed.
606 * This is the grid in which we write down our final
607 * deductions. y-coordinates in here are _not_ transformed.
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
615 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
617 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
619 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
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)])
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
630 static void nsolve_place(struct nsolve_usage
*usage
, int x
, int y
, int n
)
632 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
638 * Rule out all other numbers in this square.
640 for (i
= 1; i
<= cr
; i
++)
645 * Rule out this number in all other positions in the row.
647 for (i
= 0; i
< cr
; i
++)
652 * Rule out this number in all other positions in the column.
654 for (i
= 0; i
< cr
; i
++)
659 * Rule out this number in all other positions in the block.
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
;
669 * Enter the number in the result grid.
671 usage
->grid
[YUNTRANS(y
)*cr
+x
] = n
;
674 * Cross out this number from the list of numbers left to place
675 * in its row, its column and its block.
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
;
681 static int nsolve_elim(struct nsolve_usage
*usage
, int start
, int step
)
683 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
687 * Count the number of set bits within this section of the
692 for (i
= 0; i
< cr
; i
++)
693 if (usage
->cube
[start
+i
*step
]) {
707 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
]) {
708 nsolve_place(usage
, x
, y
, n
);
716 static int nsolve(int c
, int r
, digit
*grid
)
718 struct nsolve_usage
*usage
;
723 * Set up a usage structure as a clean slate (everything
726 usage
= snew(struct nsolve_usage
);
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
);
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
);
742 * Place all the clue numbers we are given.
744 for (x
= 0; x
< cr
; x
++)
745 for (y
= 0; y
< cr
; y
++)
747 nsolve_place(usage
, x
, YTRANS(y
), grid
[y
*cr
+x
]);
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
760 * Blockwise positional elimination.
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
))
770 * Row-wise positional elimination.
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
))
778 * Column-wise positional elimination.
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
))
787 * Numeric elimination.
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))
796 * If we reach here, we have made no deductions in this
797 * iteration, so the algorithm terminates.
808 for (x
= 0; x
< cr
; x
++)
809 for (y
= 0; y
< cr
; y
++)
815 /* ----------------------------------------------------------------------
816 * End of non-recursive solver code.
820 * Check whether a grid contains a valid complete puzzle.
822 static int check_valid(int c
, int r
, digit
*grid
)
828 used
= snewn(cr
, unsigned char);
831 * Check that each row contains precisely one of everything.
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
++)
846 * Check that each column contains precisely one of everything.
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
++)
861 * Check that each block contains precisely one of everything.
863 for (x
= 0; x
< cr
; x
+= r
) {
864 for (y
= 0; y
< cr
; y
+= c
) {
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
++)
883 static void symmetry_limit(game_params
*params
, int *xlim
, int *ylim
, int s
)
885 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
897 *xlim
= *ylim
= (cr
+1) / 2;
902 static int symmetries(game_params
*params
, int x
, int y
, int *output
, int s
)
904 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
913 break; /* just x,y is all we need */
918 *output
++ = cr
- 1 - x
;
923 *output
++ = cr
- 1 - y
;
927 *output
++ = cr
- 1 - y
;
932 *output
++ = cr
- 1 - x
;
938 *output
++ = cr
- 1 - x
;
939 *output
++ = cr
- 1 - y
;
947 static char *new_game_seed(game_params
*params
, random_state
*rs
)
949 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
952 struct xy
{ int x
, y
; } *locs
;
956 int coords
[16], ncoords
;
960 * Start the recursive solver with an empty grid to generate a
961 * random solved state.
963 grid
= snewn(area
, digit
);
964 memset(grid
, 0, area
);
965 ret
= rsolve(c
, r
, grid
, rs
, 1);
967 assert(check_valid(c
, r
, 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"
984 for (y
= 0; y
< cr
; y
++) {
985 for (x
= 0; x
< cr
; x
++) {
986 printf("%2.0d", grid
[y
*cr
+x
]);
997 for (y
= 0; y
< cr
; y
++) {
998 for (x
= 0; x
< cr
; x
++) {
999 printf("%2.0d", grid
[y
*cr
+x
]);
1008 * Now we have a solved grid, start removing things from it
1009 * while preserving solubility.
1011 locs
= snewn(area
, struct xy
);
1012 grid2
= snewn(area
, digit
);
1013 symmetry_limit(params
, &xlim
, &ylim
, params
->symm
);
1018 * Iterate over the grid and enumerate all the filled
1019 * squares we could empty.
1023 for (x
= 0; x
< xlim
; x
++)
1024 for (y
= 0; y
< ylim
; y
++)
1032 * Now shuffle that list.
1034 for (i
= nlocs
; i
> 1; i
--) {
1035 int p
= random_upto(rs
, i
);
1037 struct xy t
= locs
[p
];
1038 locs
[p
] = locs
[i
-1];
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
1049 for (i
= 0; i
< nlocs
; i
++) {
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;
1058 if (nsolve(c
, r
, grid2
)) {
1059 for (j
= 0; j
< ncoords
; j
++)
1060 grid
[coords
[2*j
+1]*cr
+coords
[2*j
]] = 0;
1067 * There was nothing we could remove without destroying
1079 for (y
= 0; y
< cr
; y
++) {
1080 for (x
= 0; x
< cr
; x
++) {
1081 printf("%2.0d", grid
[y
*cr
+x
]);
1090 * Now we have the grid as it will be presented to the user.
1091 * Encode it in a game seed.
1097 seed
= snewn(5 * area
, char);
1100 for (i
= 0; i
<= area
; i
++) {
1101 int n
= (i
< area ? grid
[i
] : -1);
1108 int c
= 'a' - 1 + run
;
1112 run
-= c
- ('a' - 1);
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.
1120 if (p
> seed
&& n
> 0)
1124 p
+= sprintf(p
, "%d", n
);
1128 assert(p
- seed
< 5 * area
);
1130 seed
= sresize(seed
, p
- seed
, char);
1138 static char *validate_seed(game_params
*params
, char *seed
)
1140 int area
= params
->r
* params
->r
* params
->c
* params
->c
;
1145 if (n
>= 'a' && n
<= 'z') {
1146 squares
+= n
- 'a' + 1;
1147 } else if (n
== '_') {
1149 } else if (n
> '0' && n
<= '9') {
1151 while (*seed
>= '0' && *seed
<= '9')
1154 return "Invalid character in game specification";
1158 return "Not enough data to fill grid";
1161 return "Too much data to fit in grid";
1166 static game_state
*new_game(game_params
*params
, char *seed
)
1168 game_state
*state
= snew(game_state
);
1169 int c
= params
->c
, r
= params
->r
, cr
= c
*r
, area
= cr
* cr
;
1172 state
->c
= params
->c
;
1173 state
->r
= params
->r
;
1175 state
->grid
= snewn(area
, digit
);
1176 state
->immutable
= snewn(area
, unsigned char);
1177 memset(state
->immutable
, FALSE
, area
);
1179 state
->completed
= FALSE
;
1184 if (n
>= 'a' && n
<= 'z') {
1185 int run
= n
- 'a' + 1;
1186 assert(i
+ run
<= area
);
1188 state
->grid
[i
++] = 0;
1189 } else if (n
== '_') {
1191 } else if (n
> '0' && n
<= '9') {
1193 state
->immutable
[i
] = TRUE
;
1194 state
->grid
[i
++] = atoi(seed
-1);
1195 while (*seed
>= '0' && *seed
<= '9')
1198 assert(!"We can't get here");
1206 static game_state
*dup_game(game_state
*state
)
1208 game_state
*ret
= snew(game_state
);
1209 int c
= state
->c
, r
= state
->r
, cr
= c
*r
, area
= cr
* cr
;
1214 ret
->grid
= snewn(area
, digit
);
1215 memcpy(ret
->grid
, state
->grid
, area
);
1217 ret
->immutable
= snewn(area
, unsigned char);
1218 memcpy(ret
->immutable
, state
->immutable
, area
);
1220 ret
->completed
= state
->completed
;
1225 static void free_game(game_state
*state
)
1227 sfree(state
->immutable
);
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.
1242 static game_ui
*new_ui(game_state
*state
)
1244 game_ui
*ui
= snew(game_ui
);
1246 ui
->hx
= ui
->hy
= -1;
1251 static void free_ui(game_ui
*ui
)
1256 static game_state
*make_move(game_state
*from
, game_ui
*ui
, int x
, int y
,
1259 int c
= from
->c
, r
= from
->r
, cr
= c
*r
;
1263 tx
= (x
- BORDER
) / TILE_SIZE
;
1264 ty
= (y
- BORDER
) / TILE_SIZE
;
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;
1273 return from
; /* UI activity occurred */
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
) ||
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;
1289 if (from
->immutable
[ui
->hy
*cr
+ui
->hx
])
1290 return NULL
; /* can't overwrite this square */
1292 ret
= dup_game(from
);
1293 ret
->grid
[ui
->hy
*cr
+ui
->hx
] = n
;
1294 ui
->hx
= ui
->hy
= -1;
1297 * We've made a real change to the grid. Check to see
1298 * if the game has been completed.
1300 if (!ret
->completed
&& check_valid(c
, r
, ret
->grid
)) {
1301 ret
->completed
= TRUE
;
1304 return ret
; /* made a valid move */
1310 /* ----------------------------------------------------------------------
1314 struct game_drawstate
{
1321 #define XSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1322 #define YSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1324 static void game_size(game_params
*params
, int *x
, int *y
)
1326 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1332 static float *game_colours(frontend
*fe
, game_state
*state
, int *ncolours
)
1334 float *ret
= snewn(3 * NCOLOURS
, float);
1336 frontend_default_colour(fe
, &ret
[COL_BACKGROUND
* 3]);
1338 ret
[COL_GRID
* 3 + 0] = 0.0F
;
1339 ret
[COL_GRID
* 3 + 1] = 0.0F
;
1340 ret
[COL_GRID
* 3 + 2] = 0.0F
;
1342 ret
[COL_CLUE
* 3 + 0] = 0.0F
;
1343 ret
[COL_CLUE
* 3 + 1] = 0.0F
;
1344 ret
[COL_CLUE
* 3 + 2] = 0.0F
;
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
;
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];
1354 *ncolours
= NCOLOURS
;
1358 static game_drawstate
*game_new_drawstate(game_state
*state
)
1360 struct game_drawstate
*ds
= snew(struct game_drawstate
);
1361 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1363 ds
->started
= FALSE
;
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
);
1375 static void game_free_drawstate(game_drawstate
*ds
)
1382 static void draw_number(frontend
*fe
, game_drawstate
*ds
, game_state
*state
,
1383 int x
, int y
, int hl
)
1385 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1390 if (ds
->grid
[y
*cr
+x
] == state
->grid
[y
*cr
+x
] && ds
->hl
[y
*cr
+x
] == hl
)
1391 return; /* no change required */
1393 tx
= BORDER
+ x
* TILE_SIZE
+ 2;
1394 ty
= BORDER
+ y
* TILE_SIZE
+ 2;
1410 clip(fe
, cx
, cy
, cw
, ch
);
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
);
1416 /* new number needs drawing? */
1417 if (state
->grid
[y
*cr
+x
]) {
1419 str
[0] = state
->grid
[y
*cr
+x
] + '0';
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
);
1429 draw_update(fe
, cx
, cy
, cw
, ch
);
1431 ds
->grid
[y
*cr
+x
] = state
->grid
[y
*cr
+x
];
1432 ds
->hl
[y
*cr
+x
] = hl
;
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
)
1439 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
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.
1449 draw_rect(fe
, 0, 0, XSIZE(cr
), YSIZE(cr
), COL_BACKGROUND
);
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
);
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
);
1467 * Draw any numbers which need redrawing.
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
) ||
1474 (flashtime
<= FLASH_TIME
/3 ||
1475 flashtime
>= FLASH_TIME
*2/3)));
1480 * Update the _entire_ grid if necessary.
1483 draw_update(fe
, 0, 0, XSIZE(cr
), YSIZE(cr
));
1488 static float game_anim_length(game_state
*oldstate
, game_state
*newstate
,
1494 static float game_flash_length(game_state
*oldstate
, game_state
*newstate
,
1497 if (!oldstate
->completed
&& newstate
->completed
)
1502 static int game_wants_statusbar(void)
1508 #define thegame solo
1511 const struct game thegame
= {
1512 "Solo", "games.solo", TRUE
,
1533 game_free_drawstate
,
1537 game_wants_statusbar
,
1540 #ifdef STANDALONE_SOLVER
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
) {}
1557 void fatal(char *fmt
, ...)
1561 fprintf(stderr
, "fatal error: ");
1564 vfprintf(stderr
, fmt
, ap
);
1567 fprintf(stderr
, "\n");
1571 int main(int argc
, char **argv
)
1575 int recurse
= FALSE
;
1576 char *id
= NULL
, *seed
, *err
;
1579 while (--argc
> 0) {
1581 if (!strcmp(p
, "-r")) {
1583 } else if (!strcmp(p
, "-n")) {
1585 } else if (*p
== '-') {
1586 fprintf(stderr
, "%s: unrecognised option `%s'\n", argv
[0]);
1594 fprintf(stderr
, "usage: %s [-n | -r] <game_id>\n", argv
[0]);
1598 seed
= strchr(id
, ':');
1600 fprintf(stderr
, "%s: game id expects a colon in it\n", argv
[0]);
1605 p
= decode_params(id
);
1606 err
= validate_seed(p
, seed
);
1608 fprintf(stderr
, "%s: %s\n", argv
[0], err
);
1611 s
= new_game(p
, seed
);
1614 int ret
= rsolve(p
->c
, p
->r
, s
->grid
, NULL
, 2);
1616 printf("multiple solutions detected; only first one output\n");
1619 nsolve(p
->c
, p
->r
, s
->grid
);
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
]);