2 * solo.c: the number-placing puzzle most popularly known as `Sudoku'.
6 * - it might still be nice to do some prioritisation on the
7 * removal of numbers from the grid
8 * + one possibility is to try to minimise the maximum number
9 * of filled squares in any block, which in particular ought
10 * to enforce never leaving a completely filled block in the
11 * puzzle as presented.
13 * - alternative interface modes
14 * + sudoku.com's Windows program has a palette of possible
15 * entries; you select a palette entry first and then click
16 * on the square you want it to go in, thus enabling
17 * mouse-only play. Useful for PDAs! I don't think it's
18 * actually incompatible with the current highlight-then-type
19 * approach: you _either_ highlight a palette entry and then
20 * click, _or_ you highlight a square and then type. At most
21 * one thing is ever highlighted at a time, so there's no way
23 * + `pencil marks' might be useful for more subtle forms of
24 * deduction, now we can create puzzles that require them.
28 * Solo puzzles need to be square overall (since each row and each
29 * column must contain one of every digit), but they need not be
30 * subdivided the same way internally. I am going to adopt a
31 * convention whereby I _always_ refer to `r' as the number of rows
32 * of _big_ divisions, and `c' as the number of columns of _big_
33 * divisions. Thus, a 2c by 3r puzzle looks something like this:
37 * ------+------ (Of course, you can't subdivide it the other way
38 * 1 4 5 | 6 3 2 or you'll get clashes; observe that the 4 in the
39 * 3 2 6 | 4 1 5 top left would conflict with the 4 in the second
40 * ------+------ box down on the left-hand side.)
44 * The need for a strong naming convention should now be clear:
45 * each small box is two rows of digits by three columns, while the
46 * overall puzzle has three rows of small boxes by two columns. So
47 * I will (hopefully) consistently use `r' to denote the number of
48 * rows _of small boxes_ (here 3), which is also the number of
49 * columns of digits in each small box; and `c' vice versa (here
52 * I'm also going to choose arbitrarily to list c first wherever
53 * possible: the above is a 2x3 puzzle, not a 3x2 one.
63 #ifdef STANDALONE_SOLVER
65 int solver_show_working
;
70 #define max(x,y) ((x)>(y)?(x):(y))
73 * To save space, I store digits internally as unsigned char. This
74 * imposes a hard limit of 255 on the order of the puzzle. Since
75 * even a 5x5 takes unacceptably long to generate, I don't see this
76 * as a serious limitation unless something _really_ impressive
77 * happens in computing technology; but here's a typedef anyway for
78 * general good practice.
80 typedef unsigned char digit
;
86 #define FLASH_TIME 0.4F
88 enum { SYMM_NONE
, SYMM_ROT2
, SYMM_ROT4
, SYMM_REF4
};
90 enum { DIFF_BLOCK
, DIFF_SIMPLE
, DIFF_INTERSECT
,
91 DIFF_SET
, DIFF_RECURSIVE
, DIFF_AMBIGUOUS
, DIFF_IMPOSSIBLE
};
103 int c
, r
, symm
, diff
;
109 unsigned char *immutable
; /* marks which digits are clues */
110 int completed
, cheated
;
113 static game_params
*default_params(void)
115 game_params
*ret
= snew(game_params
);
118 ret
->symm
= SYMM_ROT2
; /* a plausible default */
119 ret
->diff
= DIFF_BLOCK
; /* so is this */
124 static void free_params(game_params
*params
)
129 static game_params
*dup_params(game_params
*params
)
131 game_params
*ret
= snew(game_params
);
132 *ret
= *params
; /* structure copy */
136 static int game_fetch_preset(int i
, char **name
, game_params
**params
)
142 { "2x2 Trivial", { 2, 2, SYMM_ROT2
, DIFF_BLOCK
} },
143 { "2x3 Basic", { 2, 3, SYMM_ROT2
, DIFF_SIMPLE
} },
144 { "3x3 Trivial", { 3, 3, SYMM_ROT2
, DIFF_BLOCK
} },
145 { "3x3 Basic", { 3, 3, SYMM_ROT2
, DIFF_SIMPLE
} },
146 { "3x3 Intermediate", { 3, 3, SYMM_ROT2
, DIFF_INTERSECT
} },
147 { "3x3 Advanced", { 3, 3, SYMM_ROT2
, DIFF_SET
} },
148 { "3x3 Unreasonable", { 3, 3, SYMM_ROT2
, DIFF_RECURSIVE
} },
149 { "3x4 Basic", { 3, 4, SYMM_ROT2
, DIFF_SIMPLE
} },
150 { "4x4 Basic", { 4, 4, SYMM_ROT2
, DIFF_SIMPLE
} },
153 if (i
< 0 || i
>= lenof(presets
))
156 *name
= dupstr(presets
[i
].title
);
157 *params
= dup_params(&presets
[i
].params
);
162 static void decode_params(game_params
*ret
, char const *string
)
164 ret
->c
= ret
->r
= atoi(string
);
165 while (*string
&& isdigit((unsigned char)*string
)) string
++;
166 if (*string
== 'x') {
168 ret
->r
= atoi(string
);
169 while (*string
&& isdigit((unsigned char)*string
)) string
++;
172 if (*string
== 'r' || *string
== 'm' || *string
== 'a') {
176 while (*string
&& isdigit((unsigned char)*string
)) string
++;
177 if (sc
== 'm' && sn
== 4)
178 ret
->symm
= SYMM_REF4
;
179 if (sc
== 'r' && sn
== 4)
180 ret
->symm
= SYMM_ROT4
;
181 if (sc
== 'r' && sn
== 2)
182 ret
->symm
= SYMM_ROT2
;
184 ret
->symm
= SYMM_NONE
;
185 } else if (*string
== 'd') {
187 if (*string
== 't') /* trivial */
188 string
++, ret
->diff
= DIFF_BLOCK
;
189 else if (*string
== 'b') /* basic */
190 string
++, ret
->diff
= DIFF_SIMPLE
;
191 else if (*string
== 'i') /* intermediate */
192 string
++, ret
->diff
= DIFF_INTERSECT
;
193 else if (*string
== 'a') /* advanced */
194 string
++, ret
->diff
= DIFF_SET
;
195 else if (*string
== 'u') /* unreasonable */
196 string
++, ret
->diff
= DIFF_RECURSIVE
;
198 string
++; /* eat unknown character */
202 static char *encode_params(game_params
*params
, int full
)
206 sprintf(str
, "%dx%d", params
->c
, params
->r
);
208 switch (params
->symm
) {
209 case SYMM_REF4
: strcat(str
, "m4"); break;
210 case SYMM_ROT4
: strcat(str
, "r4"); break;
211 /* case SYMM_ROT2: strcat(str, "r2"); break; [default] */
212 case SYMM_NONE
: strcat(str
, "a"); break;
214 switch (params
->diff
) {
215 /* case DIFF_BLOCK: strcat(str, "dt"); break; [default] */
216 case DIFF_SIMPLE
: strcat(str
, "db"); break;
217 case DIFF_INTERSECT
: strcat(str
, "di"); break;
218 case DIFF_SET
: strcat(str
, "da"); break;
219 case DIFF_RECURSIVE
: strcat(str
, "du"); break;
225 static config_item
*game_configure(game_params
*params
)
230 ret
= snewn(5, config_item
);
232 ret
[0].name
= "Columns of sub-blocks";
233 ret
[0].type
= C_STRING
;
234 sprintf(buf
, "%d", params
->c
);
235 ret
[0].sval
= dupstr(buf
);
238 ret
[1].name
= "Rows of sub-blocks";
239 ret
[1].type
= C_STRING
;
240 sprintf(buf
, "%d", params
->r
);
241 ret
[1].sval
= dupstr(buf
);
244 ret
[2].name
= "Symmetry";
245 ret
[2].type
= C_CHOICES
;
246 ret
[2].sval
= ":None:2-way rotation:4-way rotation:4-way mirror";
247 ret
[2].ival
= params
->symm
;
249 ret
[3].name
= "Difficulty";
250 ret
[3].type
= C_CHOICES
;
251 ret
[3].sval
= ":Trivial:Basic:Intermediate:Advanced:Unreasonable";
252 ret
[3].ival
= params
->diff
;
262 static game_params
*custom_params(config_item
*cfg
)
264 game_params
*ret
= snew(game_params
);
266 ret
->c
= atoi(cfg
[0].sval
);
267 ret
->r
= atoi(cfg
[1].sval
);
268 ret
->symm
= cfg
[2].ival
;
269 ret
->diff
= cfg
[3].ival
;
274 static char *validate_params(game_params
*params
)
276 if (params
->c
< 2 || params
->r
< 2)
277 return "Both dimensions must be at least 2";
278 if (params
->c
> ORDER_MAX
|| params
->r
> ORDER_MAX
)
279 return "Dimensions greater than "STR(ORDER_MAX
)" are not supported";
283 /* ----------------------------------------------------------------------
284 * Full recursive Solo solver.
286 * The algorithm for this solver is shamelessly copied from a
287 * Python solver written by Andrew Wilkinson (which is GPLed, but
288 * I've reused only ideas and no code). It mostly just does the
289 * obvious recursive thing: pick an empty square, put one of the
290 * possible digits in it, recurse until all squares are filled,
291 * backtrack and change some choices if necessary.
293 * The clever bit is that every time it chooses which square to
294 * fill in next, it does so by counting the number of _possible_
295 * numbers that can go in each square, and it prioritises so that
296 * it picks a square with the _lowest_ number of possibilities. The
297 * idea is that filling in lots of the obvious bits (particularly
298 * any squares with only one possibility) will cut down on the list
299 * of possibilities for other squares and hence reduce the enormous
300 * search space as much as possible as early as possible.
302 * In practice the algorithm appeared to work very well; run on
303 * sample problems from the Times it completed in well under a
304 * second on my G5 even when written in Python, and given an empty
305 * grid (so that in principle it would enumerate _all_ solved
306 * grids!) it found the first valid solution just as quickly. So
307 * with a bit more randomisation I see no reason not to use this as
312 * Internal data structure used in solver to keep track of
315 struct rsolve_coord
{ int x
, y
, r
; };
316 struct rsolve_usage
{
317 int c
, r
, cr
; /* cr == c*r */
318 /* grid is a copy of the input grid, modified as we go along */
320 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
322 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
324 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
326 /* This lists all the empty spaces remaining in the grid. */
327 struct rsolve_coord
*spaces
;
329 /* If we need randomisation in the solve, this is our random state. */
331 /* Number of solutions so far found, and maximum number we care about. */
336 * The real recursive step in the solving function.
338 static void rsolve_real(struct rsolve_usage
*usage
, digit
*grid
)
340 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
341 int i
, j
, n
, sx
, sy
, bestm
, bestr
;
345 * Firstly, check for completion! If there are no spaces left
346 * in the grid, we have a solution.
348 if (usage
->nspaces
== 0) {
351 * This is our first solution, so fill in the output grid.
353 memcpy(grid
, usage
->grid
, cr
* cr
);
360 * Otherwise, there must be at least one space. Find the most
361 * constrained space, using the `r' field as a tie-breaker.
363 bestm
= cr
+1; /* so that any space will beat it */
366 for (j
= 0; j
< usage
->nspaces
; j
++) {
367 int x
= usage
->spaces
[j
].x
, y
= usage
->spaces
[j
].y
;
371 * Find the number of digits that could go in this space.
374 for (n
= 0; n
< cr
; n
++)
375 if (!usage
->row
[y
*cr
+n
] && !usage
->col
[x
*cr
+n
] &&
376 !usage
->blk
[((y
/c
)*c
+(x
/r
))*cr
+n
])
379 if (m
< bestm
|| (m
== bestm
&& usage
->spaces
[j
].r
< bestr
)) {
381 bestr
= usage
->spaces
[j
].r
;
389 * Swap that square into the final place in the spaces array,
390 * so that decrementing nspaces will remove it from the list.
392 if (i
!= usage
->nspaces
-1) {
393 struct rsolve_coord t
;
394 t
= usage
->spaces
[usage
->nspaces
-1];
395 usage
->spaces
[usage
->nspaces
-1] = usage
->spaces
[i
];
396 usage
->spaces
[i
] = t
;
400 * Now we've decided which square to start our recursion at,
401 * simply go through all possible values, shuffling them
402 * randomly first if necessary.
404 digits
= snewn(bestm
, int);
406 for (n
= 0; n
< cr
; n
++)
407 if (!usage
->row
[sy
*cr
+n
] && !usage
->col
[sx
*cr
+n
] &&
408 !usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
]) {
414 for (i
= j
; i
> 1; i
--) {
415 int p
= random_upto(usage
->rs
, i
);
418 digits
[p
] = digits
[i
-1];
424 /* And finally, go through the digit list and actually recurse. */
425 for (i
= 0; i
< j
; i
++) {
428 /* Update the usage structure to reflect the placing of this digit. */
429 usage
->row
[sy
*cr
+n
-1] = usage
->col
[sx
*cr
+n
-1] =
430 usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
-1] = TRUE
;
431 usage
->grid
[sy
*cr
+sx
] = n
;
434 /* Call the solver recursively. */
435 rsolve_real(usage
, grid
);
438 * If we have seen as many solutions as we need, terminate
439 * all processing immediately.
441 if (usage
->solns
>= usage
->maxsolns
)
444 /* Revert the usage structure. */
445 usage
->row
[sy
*cr
+n
-1] = usage
->col
[sx
*cr
+n
-1] =
446 usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
-1] = FALSE
;
447 usage
->grid
[sy
*cr
+sx
] = 0;
455 * Entry point to solver. You give it dimensions and a starting
456 * grid, which is simply an array of N^4 digits. In that array, 0
457 * means an empty square, and 1..N mean a clue square.
459 * Return value is the number of solutions found; searching will
460 * stop after the provided `max'. (Thus, you can pass max==1 to
461 * indicate that you only care about finding _one_ solution, or
462 * max==2 to indicate that you want to know the difference between
463 * a unique and non-unique solution.) The input parameter `grid' is
464 * also filled in with the _first_ (or only) solution found by the
467 static int rsolve(int c
, int r
, digit
*grid
, random_state
*rs
, int max
)
469 struct rsolve_usage
*usage
;
474 * Create an rsolve_usage structure.
476 usage
= snew(struct rsolve_usage
);
482 usage
->grid
= snewn(cr
* cr
, digit
);
483 memcpy(usage
->grid
, grid
, cr
* cr
);
485 usage
->row
= snewn(cr
* cr
, unsigned char);
486 usage
->col
= snewn(cr
* cr
, unsigned char);
487 usage
->blk
= snewn(cr
* cr
, unsigned char);
488 memset(usage
->row
, FALSE
, cr
* cr
);
489 memset(usage
->col
, FALSE
, cr
* cr
);
490 memset(usage
->blk
, FALSE
, cr
* cr
);
492 usage
->spaces
= snewn(cr
* cr
, struct rsolve_coord
);
496 usage
->maxsolns
= max
;
501 * Now fill it in with data from the input grid.
503 for (y
= 0; y
< cr
; y
++) {
504 for (x
= 0; x
< cr
; x
++) {
505 int v
= grid
[y
*cr
+x
];
507 usage
->spaces
[usage
->nspaces
].x
= x
;
508 usage
->spaces
[usage
->nspaces
].y
= y
;
510 usage
->spaces
[usage
->nspaces
].r
= random_bits(rs
, 31);
512 usage
->spaces
[usage
->nspaces
].r
= usage
->nspaces
;
515 usage
->row
[y
*cr
+v
-1] = TRUE
;
516 usage
->col
[x
*cr
+v
-1] = TRUE
;
517 usage
->blk
[((y
/c
)*c
+(x
/r
))*cr
+v
-1] = TRUE
;
523 * Run the real recursive solving function.
525 rsolve_real(usage
, grid
);
529 * Clean up the usage structure now we have our answer.
531 sfree(usage
->spaces
);
544 /* ----------------------------------------------------------------------
545 * End of recursive solver code.
548 /* ----------------------------------------------------------------------
549 * Less capable non-recursive solver. This one is used to check
550 * solubility of a grid as we gradually remove numbers from it: by
551 * verifying a grid using this solver we can ensure it isn't _too_
552 * hard (e.g. does not actually require guessing and backtracking).
554 * It supports a variety of specific modes of reasoning. By
555 * enabling or disabling subsets of these modes we can arrange a
556 * range of difficulty levels.
560 * Modes of reasoning currently supported:
562 * - Positional elimination: a number must go in a particular
563 * square because all the other empty squares in a given
564 * row/col/blk are ruled out.
566 * - Numeric elimination: a square must have a particular number
567 * in because all the other numbers that could go in it are
570 * - Intersectional analysis: given two domains which overlap
571 * (hence one must be a block, and the other can be a row or
572 * col), if the possible locations for a particular number in
573 * one of the domains can be narrowed down to the overlap, then
574 * that number can be ruled out everywhere but the overlap in
575 * the other domain too.
577 * - Set elimination: if there is a subset of the empty squares
578 * within a domain such that the union of the possible numbers
579 * in that subset has the same size as the subset itself, then
580 * those numbers can be ruled out everywhere else in the domain.
581 * (For example, if there are five empty squares and the
582 * possible numbers in each are 12, 23, 13, 134 and 1345, then
583 * the first three empty squares form such a subset: the numbers
584 * 1, 2 and 3 _must_ be in those three squares in some
585 * permutation, and hence we can deduce none of them can be in
586 * the fourth or fifth squares.)
587 * + You can also see this the other way round, concentrating
588 * on numbers rather than squares: if there is a subset of
589 * the unplaced numbers within a domain such that the union
590 * of all their possible positions has the same size as the
591 * subset itself, then all other numbers can be ruled out for
592 * those positions. However, it turns out that this is
593 * exactly equivalent to the first formulation at all times:
594 * there is a 1-1 correspondence between suitable subsets of
595 * the unplaced numbers and suitable subsets of the unfilled
596 * places, found by taking the _complement_ of the union of
597 * the numbers' possible positions (or the spaces' possible
602 * Within this solver, I'm going to transform all y-coordinates by
603 * inverting the significance of the block number and the position
604 * within the block. That is, we will start with the top row of
605 * each block in order, then the second row of each block in order,
608 * This transformation has the enormous advantage that it means
609 * every row, column _and_ block is described by an arithmetic
610 * progression of coordinates within the cubic array, so that I can
611 * use the same very simple function to do blockwise, row-wise and
612 * column-wise elimination.
614 #define YTRANS(y) (((y)%c)*r+(y)/c)
615 #define YUNTRANS(y) (((y)%r)*c+(y)/r)
617 struct nsolve_usage
{
620 * We set up a cubic array, indexed by x, y and digit; each
621 * element of this array is TRUE or FALSE according to whether
622 * or not that digit _could_ in principle go in that position.
624 * The way to index this array is cube[(x*cr+y)*cr+n-1].
625 * y-coordinates in here are transformed.
629 * This is the grid in which we write down our final
630 * deductions. y-coordinates in here are _not_ transformed.
634 * Now we keep track, at a slightly higher level, of what we
635 * have yet to work out, to prevent doing the same deduction
638 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
640 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
642 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
645 #define cubepos(x,y,n) (((x)*usage->cr+(y))*usage->cr+(n)-1)
646 #define cube(x,y,n) (usage->cube[cubepos(x,y,n)])
649 * Function called when we are certain that a particular square has
650 * a particular number in it. The y-coordinate passed in here is
653 static void nsolve_place(struct nsolve_usage
*usage
, int x
, int y
, int n
)
655 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
661 * Rule out all other numbers in this square.
663 for (i
= 1; i
<= cr
; i
++)
668 * Rule out this number in all other positions in the row.
670 for (i
= 0; i
< cr
; i
++)
675 * Rule out this number in all other positions in the column.
677 for (i
= 0; i
< cr
; i
++)
682 * Rule out this number in all other positions in the block.
686 for (i
= 0; i
< r
; i
++)
687 for (j
= 0; j
< c
; j
++)
688 if (bx
+i
!= x
|| by
+j
*r
!= y
)
689 cube(bx
+i
,by
+j
*r
,n
) = FALSE
;
692 * Enter the number in the result grid.
694 usage
->grid
[YUNTRANS(y
)*cr
+x
] = n
;
697 * Cross out this number from the list of numbers left to place
698 * in its row, its column and its block.
700 usage
->row
[y
*cr
+n
-1] = usage
->col
[x
*cr
+n
-1] =
701 usage
->blk
[((y
%r
)*c
+(x
/r
))*cr
+n
-1] = TRUE
;
704 static int nsolve_elim(struct nsolve_usage
*usage
, int start
, int step
705 #ifdef STANDALONE_SOLVER
710 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
714 * Count the number of set bits within this section of the
719 for (i
= 0; i
< cr
; i
++)
720 if (usage
->cube
[start
+i
*step
]) {
734 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
]) {
735 #ifdef STANDALONE_SOLVER
736 if (solver_show_working
) {
741 printf(":\n placing %d at (%d,%d)\n",
742 n
, 1+x
, 1+YUNTRANS(y
));
745 nsolve_place(usage
, x
, y
, n
);
753 static int nsolve_intersect(struct nsolve_usage
*usage
,
754 int start1
, int step1
, int start2
, int step2
755 #ifdef STANDALONE_SOLVER
760 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
764 * Loop over the first domain and see if there's any set bit
765 * not also in the second.
767 for (i
= 0; i
< cr
; i
++) {
768 int p
= start1
+i
*step1
;
769 if (usage
->cube
[p
] &&
770 !(p
>= start2
&& p
< start2
+cr
*step2
&&
771 (p
- start2
) % step2
== 0))
772 return FALSE
; /* there is, so we can't deduce */
776 * We have determined that all set bits in the first domain are
777 * within its overlap with the second. So loop over the second
778 * domain and remove all set bits that aren't also in that
779 * overlap; return TRUE iff we actually _did_ anything.
782 for (i
= 0; i
< cr
; i
++) {
783 int p
= start2
+i
*step2
;
784 if (usage
->cube
[p
] &&
785 !(p
>= start1
&& p
< start1
+cr
*step1
&& (p
- start1
) % step1
== 0))
787 #ifdef STANDALONE_SOLVER
788 if (solver_show_working
) {
804 printf(" ruling out %d at (%d,%d)\n",
805 pn
, 1+px
, 1+YUNTRANS(py
));
808 ret
= TRUE
; /* we did something */
816 static int nsolve_set(struct nsolve_usage
*usage
,
817 int start
, int step1
, int step2
818 #ifdef STANDALONE_SOLVER
823 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
825 unsigned char *grid
= snewn(cr
*cr
, unsigned char);
826 unsigned char *rowidx
= snewn(cr
, unsigned char);
827 unsigned char *colidx
= snewn(cr
, unsigned char);
828 unsigned char *set
= snewn(cr
, unsigned char);
831 * We are passed a cr-by-cr matrix of booleans. Our first job
832 * is to winnow it by finding any definite placements - i.e.
833 * any row with a solitary 1 - and discarding that row and the
834 * column containing the 1.
836 memset(rowidx
, TRUE
, cr
);
837 memset(colidx
, TRUE
, cr
);
838 for (i
= 0; i
< cr
; i
++) {
839 int count
= 0, first
= -1;
840 for (j
= 0; j
< cr
; j
++)
841 if (usage
->cube
[start
+i
*step1
+j
*step2
])
845 * This condition actually marks a completely insoluble
846 * (i.e. internally inconsistent) puzzle. We return and
847 * report no progress made.
852 rowidx
[i
] = colidx
[first
] = FALSE
;
856 * Convert each of rowidx/colidx from a list of 0s and 1s to a
857 * list of the indices of the 1s.
859 for (i
= j
= 0; i
< cr
; i
++)
863 for (i
= j
= 0; i
< cr
; i
++)
869 * And create the smaller matrix.
871 for (i
= 0; i
< n
; i
++)
872 for (j
= 0; j
< n
; j
++)
873 grid
[i
*cr
+j
] = usage
->cube
[start
+rowidx
[i
]*step1
+colidx
[j
]*step2
];
876 * Having done that, we now have a matrix in which every row
877 * has at least two 1s in. Now we search to see if we can find
878 * a rectangle of zeroes (in the set-theoretic sense of
879 * `rectangle', i.e. a subset of rows crossed with a subset of
880 * columns) whose width and height add up to n.
887 * We have a candidate set. If its size is <=1 or >=n-1
888 * then we move on immediately.
890 if (count
> 1 && count
< n
-1) {
892 * The number of rows we need is n-count. See if we can
893 * find that many rows which each have a zero in all
894 * the positions listed in `set'.
897 for (i
= 0; i
< n
; i
++) {
899 for (j
= 0; j
< n
; j
++)
900 if (set
[j
] && grid
[i
*cr
+j
]) {
909 * We expect never to be able to get _more_ than
910 * n-count suitable rows: this would imply that (for
911 * example) there are four numbers which between them
912 * have at most three possible positions, and hence it
913 * indicates a faulty deduction before this point or
916 assert(rows
<= n
- count
);
917 if (rows
>= n
- count
) {
918 int progress
= FALSE
;
921 * We've got one! Now, for each row which _doesn't_
922 * satisfy the criterion, eliminate all its set
923 * bits in the positions _not_ listed in `set'.
924 * Return TRUE (meaning progress has been made) if
925 * we successfully eliminated anything at all.
927 * This involves referring back through
928 * rowidx/colidx in order to work out which actual
929 * positions in the cube to meddle with.
931 for (i
= 0; i
< n
; i
++) {
933 for (j
= 0; j
< n
; j
++)
934 if (set
[j
] && grid
[i
*cr
+j
]) {
939 for (j
= 0; j
< n
; j
++)
940 if (!set
[j
] && grid
[i
*cr
+j
]) {
941 int fpos
= (start
+rowidx
[i
]*step1
+
943 #ifdef STANDALONE_SOLVER
944 if (solver_show_working
) {
960 printf(" ruling out %d at (%d,%d)\n",
961 pn
, 1+px
, 1+YUNTRANS(py
));
965 usage
->cube
[fpos
] = FALSE
;
981 * Binary increment: change the rightmost 0 to a 1, and
982 * change all 1s to the right of it to 0s.
985 while (i
> 0 && set
[i
-1])
986 set
[--i
] = 0, count
--;
988 set
[--i
] = 1, count
++;
1001 static int nsolve(int c
, int r
, digit
*grid
)
1003 struct nsolve_usage
*usage
;
1006 int diff
= DIFF_BLOCK
;
1009 * Set up a usage structure as a clean slate (everything
1012 usage
= snew(struct nsolve_usage
);
1016 usage
->cube
= snewn(cr
*cr
*cr
, unsigned char);
1017 usage
->grid
= grid
; /* write straight back to the input */
1018 memset(usage
->cube
, TRUE
, cr
*cr
*cr
);
1020 usage
->row
= snewn(cr
* cr
, unsigned char);
1021 usage
->col
= snewn(cr
* cr
, unsigned char);
1022 usage
->blk
= snewn(cr
* cr
, unsigned char);
1023 memset(usage
->row
, FALSE
, cr
* cr
);
1024 memset(usage
->col
, FALSE
, cr
* cr
);
1025 memset(usage
->blk
, FALSE
, cr
* cr
);
1028 * Place all the clue numbers we are given.
1030 for (x
= 0; x
< cr
; x
++)
1031 for (y
= 0; y
< cr
; y
++)
1033 nsolve_place(usage
, x
, YTRANS(y
), grid
[y
*cr
+x
]);
1036 * Now loop over the grid repeatedly trying all permitted modes
1037 * of reasoning. The loop terminates if we complete an
1038 * iteration without making any progress; we then return
1039 * failure or success depending on whether the grid is full or
1044 * I'd like to write `continue;' inside each of the
1045 * following loops, so that the solver returns here after
1046 * making some progress. However, I can't specify that I
1047 * want to continue an outer loop rather than the innermost
1048 * one, so I'm apologetically resorting to a goto.
1053 * Blockwise positional elimination.
1055 for (x
= 0; x
< cr
; x
+= r
)
1056 for (y
= 0; y
< r
; y
++)
1057 for (n
= 1; n
<= cr
; n
++)
1058 if (!usage
->blk
[(y
*c
+(x
/r
))*cr
+n
-1] &&
1059 nsolve_elim(usage
, cubepos(x
,y
,n
), r
*cr
1060 #ifdef STANDALONE_SOLVER
1061 , "positional elimination,"
1062 " block (%d,%d)", 1+x
/r
, 1+y
1065 diff
= max(diff
, DIFF_BLOCK
);
1070 * Row-wise positional elimination.
1072 for (y
= 0; y
< cr
; y
++)
1073 for (n
= 1; n
<= cr
; n
++)
1074 if (!usage
->row
[y
*cr
+n
-1] &&
1075 nsolve_elim(usage
, cubepos(0,y
,n
), cr
*cr
1076 #ifdef STANDALONE_SOLVER
1077 , "positional elimination,"
1078 " row %d", 1+YUNTRANS(y
)
1081 diff
= max(diff
, DIFF_SIMPLE
);
1085 * Column-wise positional elimination.
1087 for (x
= 0; x
< cr
; x
++)
1088 for (n
= 1; n
<= cr
; n
++)
1089 if (!usage
->col
[x
*cr
+n
-1] &&
1090 nsolve_elim(usage
, cubepos(x
,0,n
), cr
1091 #ifdef STANDALONE_SOLVER
1092 , "positional elimination," " column %d", 1+x
1095 diff
= max(diff
, DIFF_SIMPLE
);
1100 * Numeric elimination.
1102 for (x
= 0; x
< cr
; x
++)
1103 for (y
= 0; y
< cr
; y
++)
1104 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
] &&
1105 nsolve_elim(usage
, cubepos(x
,y
,1), 1
1106 #ifdef STANDALONE_SOLVER
1107 , "numeric elimination at (%d,%d)", 1+x
,
1111 diff
= max(diff
, DIFF_SIMPLE
);
1116 * Intersectional analysis, rows vs blocks.
1118 for (y
= 0; y
< cr
; y
++)
1119 for (x
= 0; x
< cr
; x
+= r
)
1120 for (n
= 1; n
<= cr
; n
++)
1121 if (!usage
->row
[y
*cr
+n
-1] &&
1122 !usage
->blk
[((y
%r
)*c
+(x
/r
))*cr
+n
-1] &&
1123 (nsolve_intersect(usage
, cubepos(0,y
,n
), cr
*cr
,
1124 cubepos(x
,y
%r
,n
), r
*cr
1125 #ifdef STANDALONE_SOLVER
1126 , "intersectional analysis,"
1127 " row %d vs block (%d,%d)",
1128 1+YUNTRANS(y
), 1+x
/r
, 1+y
%r
1131 nsolve_intersect(usage
, cubepos(x
,y
%r
,n
), r
*cr
,
1132 cubepos(0,y
,n
), cr
*cr
1133 #ifdef STANDALONE_SOLVER
1134 , "intersectional analysis,"
1135 " block (%d,%d) vs row %d",
1136 1+x
/r
, 1+y
%r
, 1+YUNTRANS(y
)
1139 diff
= max(diff
, DIFF_INTERSECT
);
1144 * Intersectional analysis, columns vs blocks.
1146 for (x
= 0; x
< cr
; x
++)
1147 for (y
= 0; y
< r
; y
++)
1148 for (n
= 1; n
<= cr
; n
++)
1149 if (!usage
->col
[x
*cr
+n
-1] &&
1150 !usage
->blk
[(y
*c
+(x
/r
))*cr
+n
-1] &&
1151 (nsolve_intersect(usage
, cubepos(x
,0,n
), cr
,
1152 cubepos((x
/r
)*r
,y
,n
), r
*cr
1153 #ifdef STANDALONE_SOLVER
1154 , "intersectional analysis,"
1155 " column %d vs block (%d,%d)",
1159 nsolve_intersect(usage
, cubepos((x
/r
)*r
,y
,n
), r
*cr
,
1161 #ifdef STANDALONE_SOLVER
1162 , "intersectional analysis,"
1163 " block (%d,%d) vs column %d",
1167 diff
= max(diff
, DIFF_INTERSECT
);
1172 * Blockwise set elimination.
1174 for (x
= 0; x
< cr
; x
+= r
)
1175 for (y
= 0; y
< r
; y
++)
1176 if (nsolve_set(usage
, cubepos(x
,y
,1), r
*cr
, 1
1177 #ifdef STANDALONE_SOLVER
1178 , "set elimination, block (%d,%d)", 1+x
/r
, 1+y
1181 diff
= max(diff
, DIFF_SET
);
1186 * Row-wise set elimination.
1188 for (y
= 0; y
< cr
; y
++)
1189 if (nsolve_set(usage
, cubepos(0,y
,1), cr
*cr
, 1
1190 #ifdef STANDALONE_SOLVER
1191 , "set elimination, row %d", 1+YUNTRANS(y
)
1194 diff
= max(diff
, DIFF_SET
);
1199 * Column-wise set elimination.
1201 for (x
= 0; x
< cr
; x
++)
1202 if (nsolve_set(usage
, cubepos(x
,0,1), cr
, 1
1203 #ifdef STANDALONE_SOLVER
1204 , "set elimination, column %d", 1+x
1207 diff
= max(diff
, DIFF_SET
);
1212 * If we reach here, we have made no deductions in this
1213 * iteration, so the algorithm terminates.
1224 for (x
= 0; x
< cr
; x
++)
1225 for (y
= 0; y
< cr
; y
++)
1227 return DIFF_IMPOSSIBLE
;
1231 /* ----------------------------------------------------------------------
1232 * End of non-recursive solver code.
1236 * Check whether a grid contains a valid complete puzzle.
1238 static int check_valid(int c
, int r
, digit
*grid
)
1241 unsigned char *used
;
1244 used
= snewn(cr
, unsigned char);
1247 * Check that each row contains precisely one of everything.
1249 for (y
= 0; y
< cr
; y
++) {
1250 memset(used
, FALSE
, cr
);
1251 for (x
= 0; x
< cr
; x
++)
1252 if (grid
[y
*cr
+x
] > 0 && grid
[y
*cr
+x
] <= cr
)
1253 used
[grid
[y
*cr
+x
]-1] = TRUE
;
1254 for (n
= 0; n
< cr
; n
++)
1262 * Check that each column contains precisely one of everything.
1264 for (x
= 0; x
< cr
; x
++) {
1265 memset(used
, FALSE
, cr
);
1266 for (y
= 0; y
< cr
; y
++)
1267 if (grid
[y
*cr
+x
] > 0 && grid
[y
*cr
+x
] <= cr
)
1268 used
[grid
[y
*cr
+x
]-1] = TRUE
;
1269 for (n
= 0; n
< cr
; n
++)
1277 * Check that each block contains precisely one of everything.
1279 for (x
= 0; x
< cr
; x
+= r
) {
1280 for (y
= 0; y
< cr
; y
+= c
) {
1282 memset(used
, FALSE
, cr
);
1283 for (xx
= x
; xx
< x
+r
; xx
++)
1284 for (yy
= 0; yy
< y
+c
; yy
++)
1285 if (grid
[yy
*cr
+xx
] > 0 && grid
[yy
*cr
+xx
] <= cr
)
1286 used
[grid
[yy
*cr
+xx
]-1] = TRUE
;
1287 for (n
= 0; n
< cr
; n
++)
1299 static void symmetry_limit(game_params
*params
, int *xlim
, int *ylim
, int s
)
1301 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1313 *xlim
= *ylim
= (cr
+1) / 2;
1318 static int symmetries(game_params
*params
, int x
, int y
, int *output
, int s
)
1320 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1329 break; /* just x,y is all we need */
1334 *output
++ = cr
- 1 - x
;
1339 *output
++ = cr
- 1 - y
;
1343 *output
++ = cr
- 1 - y
;
1348 *output
++ = cr
- 1 - x
;
1354 *output
++ = cr
- 1 - x
;
1355 *output
++ = cr
- 1 - y
;
1363 struct game_aux_info
{
1368 static char *new_game_desc(game_params
*params
, random_state
*rs
,
1369 game_aux_info
**aux
)
1371 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1373 digit
*grid
, *grid2
;
1374 struct xy
{ int x
, y
; } *locs
;
1378 int coords
[16], ncoords
;
1380 int maxdiff
, recursing
;
1383 * Adjust the maximum difficulty level to be consistent with
1384 * the puzzle size: all 2x2 puzzles appear to be Trivial
1385 * (DIFF_BLOCK) so we cannot hold out for even a Basic
1386 * (DIFF_SIMPLE) one.
1388 maxdiff
= params
->diff
;
1389 if (c
== 2 && r
== 2)
1390 maxdiff
= DIFF_BLOCK
;
1392 grid
= snewn(area
, digit
);
1393 locs
= snewn(area
, struct xy
);
1394 grid2
= snewn(area
, digit
);
1397 * Loop until we get a grid of the required difficulty. This is
1398 * nasty, but it seems to be unpleasantly hard to generate
1399 * difficult grids otherwise.
1403 * Start the recursive solver with an empty grid to generate a
1404 * random solved state.
1406 memset(grid
, 0, area
);
1407 ret
= rsolve(c
, r
, grid
, rs
, 1);
1409 assert(check_valid(c
, r
, grid
));
1412 * Save the solved grid in the aux_info.
1415 game_aux_info
*ai
= snew(game_aux_info
);
1418 ai
->grid
= snewn(cr
* cr
, digit
);
1419 memcpy(ai
->grid
, grid
, cr
* cr
* sizeof(digit
));
1424 * Now we have a solved grid, start removing things from it
1425 * while preserving solubility.
1427 symmetry_limit(params
, &xlim
, &ylim
, params
->symm
);
1433 * Iterate over the grid and enumerate all the filled
1434 * squares we could empty.
1438 for (x
= 0; x
< xlim
; x
++)
1439 for (y
= 0; y
< ylim
; y
++)
1447 * Now shuffle that list.
1449 for (i
= nlocs
; i
> 1; i
--) {
1450 int p
= random_upto(rs
, i
);
1452 struct xy t
= locs
[p
];
1453 locs
[p
] = locs
[i
-1];
1459 * Now loop over the shuffled list and, for each element,
1460 * see whether removing that element (and its reflections)
1461 * from the grid will still leave the grid soluble by
1464 for (i
= 0; i
< nlocs
; i
++) {
1470 memcpy(grid2
, grid
, area
);
1471 ncoords
= symmetries(params
, x
, y
, coords
, params
->symm
);
1472 for (j
= 0; j
< ncoords
; j
++)
1473 grid2
[coords
[2*j
+1]*cr
+coords
[2*j
]] = 0;
1476 ret
= (rsolve(c
, r
, grid2
, NULL
, 2) == 1);
1478 ret
= (nsolve(c
, r
, grid2
) <= maxdiff
);
1481 for (j
= 0; j
< ncoords
; j
++)
1482 grid
[coords
[2*j
+1]*cr
+coords
[2*j
]] = 0;
1489 * There was nothing we could remove without
1490 * destroying solvability. If we're trying to
1491 * generate a recursion-only grid and haven't
1492 * switched over to rsolve yet, we now do;
1493 * otherwise we give up.
1495 if (maxdiff
== DIFF_RECURSIVE
&& !recursing
) {
1503 memcpy(grid2
, grid
, area
);
1504 } while (nsolve(c
, r
, grid2
) < maxdiff
);
1510 * Now we have the grid as it will be presented to the user.
1511 * Encode it in a game desc.
1517 desc
= snewn(5 * area
, char);
1520 for (i
= 0; i
<= area
; i
++) {
1521 int n
= (i
< area ? grid
[i
] : -1);
1528 int c
= 'a' - 1 + run
;
1532 run
-= c
- ('a' - 1);
1536 * If there's a number in the very top left or
1537 * bottom right, there's no point putting an
1538 * unnecessary _ before or after it.
1540 if (p
> desc
&& n
> 0)
1544 p
+= sprintf(p
, "%d", n
);
1548 assert(p
- desc
< 5 * area
);
1550 desc
= sresize(desc
, p
- desc
, char);
1558 static void game_free_aux_info(game_aux_info
*aux
)
1564 static char *validate_desc(game_params
*params
, char *desc
)
1566 int area
= params
->r
* params
->r
* params
->c
* params
->c
;
1571 if (n
>= 'a' && n
<= 'z') {
1572 squares
+= n
- 'a' + 1;
1573 } else if (n
== '_') {
1575 } else if (n
> '0' && n
<= '9') {
1577 while (*desc
>= '0' && *desc
<= '9')
1580 return "Invalid character in game description";
1584 return "Not enough data to fill grid";
1587 return "Too much data to fit in grid";
1592 static game_state
*new_game(game_params
*params
, char *desc
)
1594 game_state
*state
= snew(game_state
);
1595 int c
= params
->c
, r
= params
->r
, cr
= c
*r
, area
= cr
* cr
;
1598 state
->c
= params
->c
;
1599 state
->r
= params
->r
;
1601 state
->grid
= snewn(area
, digit
);
1602 state
->immutable
= snewn(area
, unsigned char);
1603 memset(state
->immutable
, FALSE
, area
);
1605 state
->completed
= state
->cheated
= FALSE
;
1610 if (n
>= 'a' && n
<= 'z') {
1611 int run
= n
- 'a' + 1;
1612 assert(i
+ run
<= area
);
1614 state
->grid
[i
++] = 0;
1615 } else if (n
== '_') {
1617 } else if (n
> '0' && n
<= '9') {
1619 state
->immutable
[i
] = TRUE
;
1620 state
->grid
[i
++] = atoi(desc
-1);
1621 while (*desc
>= '0' && *desc
<= '9')
1624 assert(!"We can't get here");
1632 static game_state
*dup_game(game_state
*state
)
1634 game_state
*ret
= snew(game_state
);
1635 int c
= state
->c
, r
= state
->r
, cr
= c
*r
, area
= cr
* cr
;
1640 ret
->grid
= snewn(area
, digit
);
1641 memcpy(ret
->grid
, state
->grid
, area
);
1643 ret
->immutable
= snewn(area
, unsigned char);
1644 memcpy(ret
->immutable
, state
->immutable
, area
);
1646 ret
->completed
= state
->completed
;
1647 ret
->cheated
= state
->cheated
;
1652 static void free_game(game_state
*state
)
1654 sfree(state
->immutable
);
1659 static game_state
*solve_game(game_state
*state
, game_aux_info
*ai
,
1663 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1666 ret
= dup_game(state
);
1667 ret
->completed
= ret
->cheated
= TRUE
;
1670 * If we already have the solution in the aux_info, save
1671 * ourselves some time.
1677 memcpy(ret
->grid
, ai
->grid
, cr
* cr
* sizeof(digit
));
1680 rsolve_ret
= rsolve(c
, r
, ret
->grid
, NULL
, 2);
1682 if (rsolve_ret
!= 1) {
1684 if (rsolve_ret
== 0)
1685 *error
= "No solution exists for this puzzle";
1687 *error
= "Multiple solutions exist for this puzzle";
1695 static char *grid_text_format(int c
, int r
, digit
*grid
)
1703 * There are cr lines of digits, plus r-1 lines of block
1704 * separators. Each line contains cr digits, cr-1 separating
1705 * spaces, and c-1 two-character block separators. Thus, the
1706 * total length of a line is 2*cr+2*c-3 (not counting the
1707 * newline), and there are cr+r-1 of them.
1709 maxlen
= (cr
+r
-1) * (2*cr
+2*c
-2);
1710 ret
= snewn(maxlen
+1, char);
1713 for (y
= 0; y
< cr
; y
++) {
1714 for (x
= 0; x
< cr
; x
++) {
1715 int ch
= grid
[y
* cr
+ x
];
1725 if ((x
+1) % r
== 0) {
1732 if (y
+1 < cr
&& (y
+1) % c
== 0) {
1733 for (x
= 0; x
< cr
; x
++) {
1737 if ((x
+1) % r
== 0) {
1747 assert(p
- ret
== maxlen
);
1752 static char *game_text_format(game_state
*state
)
1754 return grid_text_format(state
->c
, state
->r
, state
->grid
);
1759 * These are the coordinates of the currently highlighted
1760 * square on the grid, or -1,-1 if there isn't one. When there
1761 * is, pressing a valid number or letter key or Space will
1762 * enter that number or letter in the grid.
1767 static game_ui
*new_ui(game_state
*state
)
1769 game_ui
*ui
= snew(game_ui
);
1771 ui
->hx
= ui
->hy
= -1;
1776 static void free_ui(game_ui
*ui
)
1781 static game_state
*make_move(game_state
*from
, game_ui
*ui
, int x
, int y
,
1784 int c
= from
->c
, r
= from
->r
, cr
= c
*r
;
1788 button
&= ~MOD_NUM_KEYPAD
; /* we treat this the same as normal */
1790 tx
= (x
+ TILE_SIZE
- BORDER
) / TILE_SIZE
- 1;
1791 ty
= (y
+ TILE_SIZE
- BORDER
) / TILE_SIZE
- 1;
1793 if (tx
>= 0 && tx
< cr
&& ty
>= 0 && ty
< cr
&& button
== LEFT_BUTTON
) {
1794 if (tx
== ui
->hx
&& ty
== ui
->hy
) {
1795 ui
->hx
= ui
->hy
= -1;
1800 return from
; /* UI activity occurred */
1803 if (ui
->hx
!= -1 && ui
->hy
!= -1 &&
1804 ((button
>= '1' && button
<= '9' && button
- '0' <= cr
) ||
1805 (button
>= 'a' && button
<= 'z' && button
- 'a' + 10 <= cr
) ||
1806 (button
>= 'A' && button
<= 'Z' && button
- 'A' + 10 <= cr
) ||
1808 int n
= button
- '0';
1809 if (button
>= 'A' && button
<= 'Z')
1810 n
= button
- 'A' + 10;
1811 if (button
>= 'a' && button
<= 'z')
1812 n
= button
- 'a' + 10;
1816 if (from
->immutable
[ui
->hy
*cr
+ui
->hx
])
1817 return NULL
; /* can't overwrite this square */
1819 ret
= dup_game(from
);
1820 ret
->grid
[ui
->hy
*cr
+ui
->hx
] = n
;
1821 ui
->hx
= ui
->hy
= -1;
1824 * We've made a real change to the grid. Check to see
1825 * if the game has been completed.
1827 if (!ret
->completed
&& check_valid(c
, r
, ret
->grid
)) {
1828 ret
->completed
= TRUE
;
1831 return ret
; /* made a valid move */
1837 /* ----------------------------------------------------------------------
1841 struct game_drawstate
{
1848 #define XSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1849 #define YSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1851 static void game_size(game_params
*params
, int *x
, int *y
)
1853 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1859 static float *game_colours(frontend
*fe
, game_state
*state
, int *ncolours
)
1861 float *ret
= snewn(3 * NCOLOURS
, float);
1863 frontend_default_colour(fe
, &ret
[COL_BACKGROUND
* 3]);
1865 ret
[COL_GRID
* 3 + 0] = 0.0F
;
1866 ret
[COL_GRID
* 3 + 1] = 0.0F
;
1867 ret
[COL_GRID
* 3 + 2] = 0.0F
;
1869 ret
[COL_CLUE
* 3 + 0] = 0.0F
;
1870 ret
[COL_CLUE
* 3 + 1] = 0.0F
;
1871 ret
[COL_CLUE
* 3 + 2] = 0.0F
;
1873 ret
[COL_USER
* 3 + 0] = 0.0F
;
1874 ret
[COL_USER
* 3 + 1] = 0.6F
* ret
[COL_BACKGROUND
* 3 + 1];
1875 ret
[COL_USER
* 3 + 2] = 0.0F
;
1877 ret
[COL_HIGHLIGHT
* 3 + 0] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 0];
1878 ret
[COL_HIGHLIGHT
* 3 + 1] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 1];
1879 ret
[COL_HIGHLIGHT
* 3 + 2] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 2];
1881 *ncolours
= NCOLOURS
;
1885 static game_drawstate
*game_new_drawstate(game_state
*state
)
1887 struct game_drawstate
*ds
= snew(struct game_drawstate
);
1888 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1890 ds
->started
= FALSE
;
1894 ds
->grid
= snewn(cr
*cr
, digit
);
1895 memset(ds
->grid
, 0, cr
*cr
);
1896 ds
->hl
= snewn(cr
*cr
, unsigned char);
1897 memset(ds
->hl
, 0, cr
*cr
);
1902 static void game_free_drawstate(game_drawstate
*ds
)
1909 static void draw_number(frontend
*fe
, game_drawstate
*ds
, game_state
*state
,
1910 int x
, int y
, int hl
)
1912 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1917 if (ds
->grid
[y
*cr
+x
] == state
->grid
[y
*cr
+x
] && ds
->hl
[y
*cr
+x
] == hl
)
1918 return; /* no change required */
1920 tx
= BORDER
+ x
* TILE_SIZE
+ 2;
1921 ty
= BORDER
+ y
* TILE_SIZE
+ 2;
1937 clip(fe
, cx
, cy
, cw
, ch
);
1939 /* background needs erasing? */
1940 if (ds
->grid
[y
*cr
+x
] || ds
->hl
[y
*cr
+x
] != hl
)
1941 draw_rect(fe
, cx
, cy
, cw
, ch
, hl ? COL_HIGHLIGHT
: COL_BACKGROUND
);
1943 /* new number needs drawing? */
1944 if (state
->grid
[y
*cr
+x
]) {
1946 str
[0] = state
->grid
[y
*cr
+x
] + '0';
1948 str
[0] += 'a' - ('9'+1);
1949 draw_text(fe
, tx
+ TILE_SIZE
/2, ty
+ TILE_SIZE
/2,
1950 FONT_VARIABLE
, TILE_SIZE
/2, ALIGN_VCENTRE
| ALIGN_HCENTRE
,
1951 state
->immutable
[y
*cr
+x
] ? COL_CLUE
: COL_USER
, str
);
1956 draw_update(fe
, cx
, cy
, cw
, ch
);
1958 ds
->grid
[y
*cr
+x
] = state
->grid
[y
*cr
+x
];
1959 ds
->hl
[y
*cr
+x
] = hl
;
1962 static void game_redraw(frontend
*fe
, game_drawstate
*ds
, game_state
*oldstate
,
1963 game_state
*state
, int dir
, game_ui
*ui
,
1964 float animtime
, float flashtime
)
1966 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1971 * The initial contents of the window are not guaranteed
1972 * and can vary with front ends. To be on the safe side,
1973 * all games should start by drawing a big
1974 * background-colour rectangle covering the whole window.
1976 draw_rect(fe
, 0, 0, XSIZE(cr
), YSIZE(cr
), COL_BACKGROUND
);
1981 for (x
= 0; x
<= cr
; x
++) {
1982 int thick
= (x
% r ?
0 : 1);
1983 draw_rect(fe
, BORDER
+ x
*TILE_SIZE
- thick
, BORDER
-1,
1984 1+2*thick
, cr
*TILE_SIZE
+3, COL_GRID
);
1986 for (y
= 0; y
<= cr
; y
++) {
1987 int thick
= (y
% c ?
0 : 1);
1988 draw_rect(fe
, BORDER
-1, BORDER
+ y
*TILE_SIZE
- thick
,
1989 cr
*TILE_SIZE
+3, 1+2*thick
, COL_GRID
);
1994 * Draw any numbers which need redrawing.
1996 for (x
= 0; x
< cr
; x
++) {
1997 for (y
= 0; y
< cr
; y
++) {
1998 draw_number(fe
, ds
, state
, x
, y
,
1999 (x
== ui
->hx
&& y
== ui
->hy
) ||
2001 (flashtime
<= FLASH_TIME
/3 ||
2002 flashtime
>= FLASH_TIME
*2/3)));
2007 * Update the _entire_ grid if necessary.
2010 draw_update(fe
, 0, 0, XSIZE(cr
), YSIZE(cr
));
2015 static float game_anim_length(game_state
*oldstate
, game_state
*newstate
,
2021 static float game_flash_length(game_state
*oldstate
, game_state
*newstate
,
2024 if (!oldstate
->completed
&& newstate
->completed
&&
2025 !oldstate
->cheated
&& !newstate
->cheated
)
2030 static int game_wants_statusbar(void)
2036 #define thegame solo
2039 const struct game thegame
= {
2040 "Solo", "games.solo",
2047 TRUE
, game_configure
, custom_params
,
2056 TRUE
, game_text_format
,
2063 game_free_drawstate
,
2067 game_wants_statusbar
,
2070 #ifdef STANDALONE_SOLVER
2073 * gcc -DSTANDALONE_SOLVER -o solosolver solo.c malloc.c
2076 void frontend_default_colour(frontend
*fe
, float *output
) {}
2077 void draw_text(frontend
*fe
, int x
, int y
, int fonttype
, int fontsize
,
2078 int align
, int colour
, char *text
) {}
2079 void draw_rect(frontend
*fe
, int x
, int y
, int w
, int h
, int colour
) {}
2080 void draw_line(frontend
*fe
, int x1
, int y1
, int x2
, int y2
, int colour
) {}
2081 void draw_polygon(frontend
*fe
, int *coords
, int npoints
,
2082 int fill
, int colour
) {}
2083 void clip(frontend
*fe
, int x
, int y
, int w
, int h
) {}
2084 void unclip(frontend
*fe
) {}
2085 void start_draw(frontend
*fe
) {}
2086 void draw_update(frontend
*fe
, int x
, int y
, int w
, int h
) {}
2087 void end_draw(frontend
*fe
) {}
2088 unsigned long random_bits(random_state
*state
, int bits
)
2089 { assert(!"Shouldn't get randomness"); return 0; }
2090 unsigned long random_upto(random_state
*state
, unsigned long limit
)
2091 { assert(!"Shouldn't get randomness"); return 0; }
2093 void fatal(char *fmt
, ...)
2097 fprintf(stderr
, "fatal error: ");
2100 vfprintf(stderr
, fmt
, ap
);
2103 fprintf(stderr
, "\n");
2107 int main(int argc
, char **argv
)
2112 char *id
= NULL
, *desc
, *err
;
2116 while (--argc
> 0) {
2118 if (!strcmp(p
, "-r")) {
2120 } else if (!strcmp(p
, "-n")) {
2122 } else if (!strcmp(p
, "-v")) {
2123 solver_show_working
= TRUE
;
2125 } else if (!strcmp(p
, "-g")) {
2128 } else if (*p
== '-') {
2129 fprintf(stderr
, "%s: unrecognised option `%s'\n", argv
[0]);
2137 fprintf(stderr
, "usage: %s [-n | -r | -g | -v] <game_id>\n", argv
[0]);
2141 desc
= strchr(id
, ':');
2143 fprintf(stderr
, "%s: game id expects a colon in it\n", argv
[0]);
2148 p
= decode_params(id
);
2149 err
= validate_desc(p
, desc
);
2151 fprintf(stderr
, "%s: %s\n", argv
[0], err
);
2154 s
= new_game(p
, desc
);
2157 int ret
= rsolve(p
->c
, p
->r
, s
->grid
, NULL
, 2);
2159 fprintf(stderr
, "%s: rsolve: multiple solutions detected\n",
2163 int ret
= nsolve(p
->c
, p
->r
, s
->grid
);
2165 if (ret
== DIFF_IMPOSSIBLE
) {
2167 * Now resort to rsolve to determine whether it's
2170 ret
= rsolve(p
->c
, p
->r
, s
->grid
, NULL
, 2);
2172 ret
= DIFF_IMPOSSIBLE
;
2174 ret
= DIFF_RECURSIVE
;
2176 ret
= DIFF_AMBIGUOUS
;
2178 printf("Difficulty rating: %s\n",
2179 ret
==DIFF_BLOCK ?
"Trivial (blockwise positional elimination only)":
2180 ret
==DIFF_SIMPLE ?
"Basic (row/column/number elimination required)":
2181 ret
==DIFF_INTERSECT ?
"Intermediate (intersectional analysis required)":
2182 ret
==DIFF_SET ?
"Advanced (set elimination required)":
2183 ret
==DIFF_RECURSIVE ?
"Unreasonable (guesswork and backtracking required)":
2184 ret
==DIFF_AMBIGUOUS ?
"Ambiguous (multiple solutions exist)":
2185 ret
==DIFF_IMPOSSIBLE ?
"Impossible (no solution exists)":
2186 "INTERNAL ERROR: unrecognised difficulty code");
2190 printf("%s\n", grid_text_format(p
->c
, p
->r
, s
->grid
));