2 * solo.c: the number-placing puzzle most popularly known as `Sudoku'.
6 * - reports from users are that `Trivial'-mode puzzles are still
7 * rather hard compared to newspapers' easy ones, so some better
8 * low-end difficulty grading would be nice
9 * + it's possible that really easy puzzles always have
10 * _several_ things you can do, so don't make you hunt too
11 * hard for the one deduction you can currently make
12 * + it's also possible that easy puzzles require fewer
13 * cross-eliminations: perhaps there's a higher incidence of
14 * things you can deduce by looking only at (say) rows,
15 * rather than things you have to check both rows and columns
17 * + but really, what I need to do is find some really easy
18 * puzzles and _play_ them, to see what's actually easy about
20 * + while I'm revamping this area, filling in the _last_
21 * number in a nearly-full row or column should certainly be
22 * permitted even at the lowest difficulty level.
23 * + also Owen noticed that `Basic' grids requiring numeric
24 * elimination are actually very hard, so I wonder if a
25 * difficulty gradation between that and positional-
26 * elimination-only might be in order
27 * + but it's not good to have _too_ many difficulty levels, or
28 * it'll take too long to randomly generate a given level.
30 * - it might still be nice to do some prioritisation on the
31 * removal of numbers from the grid
32 * + one possibility is to try to minimise the maximum number
33 * of filled squares in any block, which in particular ought
34 * to enforce never leaving a completely filled block in the
35 * puzzle as presented.
37 * - alternative interface modes
38 * + sudoku.com's Windows program has a palette of possible
39 * entries; you select a palette entry first and then click
40 * on the square you want it to go in, thus enabling
41 * mouse-only play. Useful for PDAs! I don't think it's
42 * actually incompatible with the current highlight-then-type
43 * approach: you _either_ highlight a palette entry and then
44 * click, _or_ you highlight a square and then type. At most
45 * one thing is ever highlighted at a time, so there's no way
47 * + then again, I don't actually like sudoku.com's interface;
48 * it's too much like a paint package whereas I prefer to
49 * think of Solo as a text editor.
50 * + another PDA-friendly possibility is a drag interface:
51 * _drag_ numbers from the palette into the grid squares.
52 * Thought experiments suggest I'd prefer that to the
53 * sudoku.com approach, but I haven't actually tried it.
57 * Solo puzzles need to be square overall (since each row and each
58 * column must contain one of every digit), but they need not be
59 * subdivided the same way internally. I am going to adopt a
60 * convention whereby I _always_ refer to `r' as the number of rows
61 * of _big_ divisions, and `c' as the number of columns of _big_
62 * divisions. Thus, a 2c by 3r puzzle looks something like this:
66 * ------+------ (Of course, you can't subdivide it the other way
67 * 1 4 5 | 6 3 2 or you'll get clashes; observe that the 4 in the
68 * 3 2 6 | 4 1 5 top left would conflict with the 4 in the second
69 * ------+------ box down on the left-hand side.)
73 * The need for a strong naming convention should now be clear:
74 * each small box is two rows of digits by three columns, while the
75 * overall puzzle has three rows of small boxes by two columns. So
76 * I will (hopefully) consistently use `r' to denote the number of
77 * rows _of small boxes_ (here 3), which is also the number of
78 * columns of digits in each small box; and `c' vice versa (here
81 * I'm also going to choose arbitrarily to list c first wherever
82 * possible: the above is a 2x3 puzzle, not a 3x2 one.
92 #ifdef STANDALONE_SOLVER
94 int solver_show_working
, solver_recurse_depth
;
100 * To save space, I store digits internally as unsigned char. This
101 * imposes a hard limit of 255 on the order of the puzzle. Since
102 * even a 5x5 takes unacceptably long to generate, I don't see this
103 * as a serious limitation unless something _really_ impressive
104 * happens in computing technology; but here's a typedef anyway for
105 * general good practice.
107 typedef unsigned char digit
;
108 #define ORDER_MAX 255
110 #define PREFERRED_TILE_SIZE 32
111 #define TILE_SIZE (ds->tilesize)
112 #define BORDER (TILE_SIZE / 2)
114 #define FLASH_TIME 0.4F
116 enum { SYMM_NONE
, SYMM_ROT2
, SYMM_ROT4
, SYMM_REF2
, SYMM_REF2D
, SYMM_REF4
,
117 SYMM_REF4D
, SYMM_REF8
};
119 enum { DIFF_BLOCK
, DIFF_SIMPLE
, DIFF_INTERSECT
, DIFF_SET
, DIFF_NEIGHBOUR
,
120 DIFF_RECURSIVE
, DIFF_AMBIGUOUS
, DIFF_IMPOSSIBLE
};
134 int c
, r
, symm
, diff
;
140 unsigned char *pencil
; /* c*r*c*r elements */
141 unsigned char *immutable
; /* marks which digits are clues */
142 int completed
, cheated
;
145 static game_params
*default_params(void)
147 game_params
*ret
= snew(game_params
);
150 ret
->symm
= SYMM_ROT2
; /* a plausible default */
151 ret
->diff
= DIFF_BLOCK
; /* so is this */
156 static void free_params(game_params
*params
)
161 static game_params
*dup_params(game_params
*params
)
163 game_params
*ret
= snew(game_params
);
164 *ret
= *params
; /* structure copy */
168 static int game_fetch_preset(int i
, char **name
, game_params
**params
)
174 { "2x2 Trivial", { 2, 2, SYMM_ROT2
, DIFF_BLOCK
} },
175 { "2x3 Basic", { 2, 3, SYMM_ROT2
, DIFF_SIMPLE
} },
176 { "3x3 Trivial", { 3, 3, SYMM_ROT2
, DIFF_BLOCK
} },
177 { "3x3 Basic", { 3, 3, SYMM_ROT2
, DIFF_SIMPLE
} },
178 { "3x3 Intermediate", { 3, 3, SYMM_ROT2
, DIFF_INTERSECT
} },
179 { "3x3 Advanced", { 3, 3, SYMM_ROT2
, DIFF_SET
} },
180 { "3x3 Extreme", { 3, 3, SYMM_ROT2
, DIFF_NEIGHBOUR
} },
181 { "3x3 Unreasonable", { 3, 3, SYMM_ROT2
, DIFF_RECURSIVE
} },
183 { "3x4 Basic", { 3, 4, SYMM_ROT2
, DIFF_SIMPLE
} },
184 { "4x4 Basic", { 4, 4, SYMM_ROT2
, DIFF_SIMPLE
} },
188 if (i
< 0 || i
>= lenof(presets
))
191 *name
= dupstr(presets
[i
].title
);
192 *params
= dup_params(&presets
[i
].params
);
197 static void decode_params(game_params
*ret
, char const *string
)
199 ret
->c
= ret
->r
= atoi(string
);
200 while (*string
&& isdigit((unsigned char)*string
)) string
++;
201 if (*string
== 'x') {
203 ret
->r
= atoi(string
);
204 while (*string
&& isdigit((unsigned char)*string
)) string
++;
207 if (*string
== 'r' || *string
== 'm' || *string
== 'a') {
210 if (*string
== 'd') {
217 while (*string
&& isdigit((unsigned char)*string
)) string
++;
218 if (sc
== 'm' && sn
== 8)
219 ret
->symm
= SYMM_REF8
;
220 if (sc
== 'm' && sn
== 4)
221 ret
->symm
= sd ? SYMM_REF4D
: SYMM_REF4
;
222 if (sc
== 'm' && sn
== 2)
223 ret
->symm
= sd ? SYMM_REF2D
: SYMM_REF2
;
224 if (sc
== 'r' && sn
== 4)
225 ret
->symm
= SYMM_ROT4
;
226 if (sc
== 'r' && sn
== 2)
227 ret
->symm
= SYMM_ROT2
;
229 ret
->symm
= SYMM_NONE
;
230 } else if (*string
== 'd') {
232 if (*string
== 't') /* trivial */
233 string
++, ret
->diff
= DIFF_BLOCK
;
234 else if (*string
== 'b') /* basic */
235 string
++, ret
->diff
= DIFF_SIMPLE
;
236 else if (*string
== 'i') /* intermediate */
237 string
++, ret
->diff
= DIFF_INTERSECT
;
238 else if (*string
== 'a') /* advanced */
239 string
++, ret
->diff
= DIFF_SET
;
240 else if (*string
== 'e') /* extreme */
241 string
++, ret
->diff
= DIFF_NEIGHBOUR
;
242 else if (*string
== 'u') /* unreasonable */
243 string
++, ret
->diff
= DIFF_RECURSIVE
;
245 string
++; /* eat unknown character */
249 static char *encode_params(game_params
*params
, int full
)
253 sprintf(str
, "%dx%d", params
->c
, params
->r
);
255 switch (params
->symm
) {
256 case SYMM_REF8
: strcat(str
, "m8"); break;
257 case SYMM_REF4
: strcat(str
, "m4"); break;
258 case SYMM_REF4D
: strcat(str
, "md4"); break;
259 case SYMM_REF2
: strcat(str
, "m2"); break;
260 case SYMM_REF2D
: strcat(str
, "md2"); break;
261 case SYMM_ROT4
: strcat(str
, "r4"); break;
262 /* case SYMM_ROT2: strcat(str, "r2"); break; [default] */
263 case SYMM_NONE
: strcat(str
, "a"); break;
265 switch (params
->diff
) {
266 /* case DIFF_BLOCK: strcat(str, "dt"); break; [default] */
267 case DIFF_SIMPLE
: strcat(str
, "db"); break;
268 case DIFF_INTERSECT
: strcat(str
, "di"); break;
269 case DIFF_SET
: strcat(str
, "da"); break;
270 case DIFF_NEIGHBOUR
: strcat(str
, "de"); break;
271 case DIFF_RECURSIVE
: strcat(str
, "du"); break;
277 static config_item
*game_configure(game_params
*params
)
282 ret
= snewn(5, config_item
);
284 ret
[0].name
= "Columns of sub-blocks";
285 ret
[0].type
= C_STRING
;
286 sprintf(buf
, "%d", params
->c
);
287 ret
[0].sval
= dupstr(buf
);
290 ret
[1].name
= "Rows of sub-blocks";
291 ret
[1].type
= C_STRING
;
292 sprintf(buf
, "%d", params
->r
);
293 ret
[1].sval
= dupstr(buf
);
296 ret
[2].name
= "Symmetry";
297 ret
[2].type
= C_CHOICES
;
298 ret
[2].sval
= ":None:2-way rotation:4-way rotation:2-way mirror:"
299 "2-way diagonal mirror:4-way mirror:4-way diagonal mirror:"
301 ret
[2].ival
= params
->symm
;
303 ret
[3].name
= "Difficulty";
304 ret
[3].type
= C_CHOICES
;
305 ret
[3].sval
= ":Trivial:Basic:Intermediate:Advanced:Extreme:Unreasonable";
306 ret
[3].ival
= params
->diff
;
316 static game_params
*custom_params(config_item
*cfg
)
318 game_params
*ret
= snew(game_params
);
320 ret
->c
= atoi(cfg
[0].sval
);
321 ret
->r
= atoi(cfg
[1].sval
);
322 ret
->symm
= cfg
[2].ival
;
323 ret
->diff
= cfg
[3].ival
;
328 static char *validate_params(game_params
*params
, int full
)
330 if (params
->c
< 2 || params
->r
< 2)
331 return "Both dimensions must be at least 2";
332 if (params
->c
> ORDER_MAX
|| params
->r
> ORDER_MAX
)
333 return "Dimensions greater than "STR(ORDER_MAX
)" are not supported";
334 if ((params
->c
* params
->r
) > 36)
335 return "Unable to support more than 36 distinct symbols in a puzzle";
339 /* ----------------------------------------------------------------------
342 * This solver is used for two purposes:
343 * + to check solubility of a grid as we gradually remove numbers
345 * + to solve an externally generated puzzle when the user selects
348 * It supports a variety of specific modes of reasoning. By
349 * enabling or disabling subsets of these modes we can arrange a
350 * range of difficulty levels.
354 * Modes of reasoning currently supported:
356 * - Positional elimination: a number must go in a particular
357 * square because all the other empty squares in a given
358 * row/col/blk are ruled out.
360 * - Numeric elimination: a square must have a particular number
361 * in because all the other numbers that could go in it are
364 * - Intersectional analysis: given two domains which overlap
365 * (hence one must be a block, and the other can be a row or
366 * col), if the possible locations for a particular number in
367 * one of the domains can be narrowed down to the overlap, then
368 * that number can be ruled out everywhere but the overlap in
369 * the other domain too.
371 * - Set elimination: if there is a subset of the empty squares
372 * within a domain such that the union of the possible numbers
373 * in that subset has the same size as the subset itself, then
374 * those numbers can be ruled out everywhere else in the domain.
375 * (For example, if there are five empty squares and the
376 * possible numbers in each are 12, 23, 13, 134 and 1345, then
377 * the first three empty squares form such a subset: the numbers
378 * 1, 2 and 3 _must_ be in those three squares in some
379 * permutation, and hence we can deduce none of them can be in
380 * the fourth or fifth squares.)
381 * + You can also see this the other way round, concentrating
382 * on numbers rather than squares: if there is a subset of
383 * the unplaced numbers within a domain such that the union
384 * of all their possible positions has the same size as the
385 * subset itself, then all other numbers can be ruled out for
386 * those positions. However, it turns out that this is
387 * exactly equivalent to the first formulation at all times:
388 * there is a 1-1 correspondence between suitable subsets of
389 * the unplaced numbers and suitable subsets of the unfilled
390 * places, found by taking the _complement_ of the union of
391 * the numbers' possible positions (or the spaces' possible
394 * - Mutual neighbour elimination: find two squares A,B and a
395 * number N in the possible set of A, such that putting N in A
396 * would rule out enough possibilities from the mutual
397 * neighbours of A and B that there would be no possibilities
398 * left for B. Thereby rule out N in A.
399 * + The simplest case of this is if B has two possibilities
400 * (wlog {1,2}), and there are two mutual neighbours of A and
401 * B which have possibilities {1,3} and {2,3}. Thus, if A
402 * were to be 3, then those neighbours would contain 1 and 2,
403 * and hence there would be nothing left which could go in B.
404 * + There can be more complex cases of it too: if A and B are
405 * in the same column of large blocks, then they can have
406 * more than two mutual neighbours, some of which can also be
407 * neighbours of one another. Suppose, for example, that B
408 * has possibilities {1,2,3}; there's one square P in the
409 * same column as B and the same block as A, with
410 * possibilities {1,4}; and there are _two_ squares Q,R in
411 * the same column as A and the same block as B with
412 * possibilities {2,3,4}. Then if A contained 4, P would
413 * contain 1, and Q and R would have to contain 2 and 3 in
414 * _some_ order; therefore, once again, B would have no
415 * remaining possibilities.
417 * - Recursion. If all else fails, we pick one of the currently
418 * most constrained empty squares and take a random guess at its
419 * contents, then continue solving on that basis and see if we
424 * Within this solver, I'm going to transform all y-coordinates by
425 * inverting the significance of the block number and the position
426 * within the block. That is, we will start with the top row of
427 * each block in order, then the second row of each block in order,
430 * This transformation has the enormous advantage that it means
431 * every row, column _and_ block is described by an arithmetic
432 * progression of coordinates within the cubic array, so that I can
433 * use the same very simple function to do blockwise, row-wise and
434 * column-wise elimination.
436 #define YTRANS(y) (((y)%c)*r+(y)/c)
437 #define YUNTRANS(y) (((y)%r)*c+(y)/r)
439 struct solver_usage
{
442 * We set up a cubic array, indexed by x, y and digit; each
443 * element of this array is TRUE or FALSE according to whether
444 * or not that digit _could_ in principle go in that position.
446 * The way to index this array is cube[(x*cr+y)*cr+n-1].
447 * y-coordinates in here are transformed.
451 * This is the grid in which we write down our final
452 * deductions. y-coordinates in here are _not_ transformed.
456 * Now we keep track, at a slightly higher level, of what we
457 * have yet to work out, to prevent doing the same deduction
460 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
462 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
464 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
467 #define cubepos(x,y,n) (((x)*usage->cr+(y))*usage->cr+(n)-1)
468 #define cube(x,y,n) (usage->cube[cubepos(x,y,n)])
471 * Function called when we are certain that a particular square has
472 * a particular number in it. The y-coordinate passed in here is
475 static void solver_place(struct solver_usage
*usage
, int x
, int y
, int n
)
477 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
483 * Rule out all other numbers in this square.
485 for (i
= 1; i
<= cr
; i
++)
490 * Rule out this number in all other positions in the row.
492 for (i
= 0; i
< cr
; i
++)
497 * Rule out this number in all other positions in the column.
499 for (i
= 0; i
< cr
; i
++)
504 * Rule out this number in all other positions in the block.
508 for (i
= 0; i
< r
; i
++)
509 for (j
= 0; j
< c
; j
++)
510 if (bx
+i
!= x
|| by
+j
*r
!= y
)
511 cube(bx
+i
,by
+j
*r
,n
) = FALSE
;
514 * Enter the number in the result grid.
516 usage
->grid
[YUNTRANS(y
)*cr
+x
] = n
;
519 * Cross out this number from the list of numbers left to place
520 * in its row, its column and its block.
522 usage
->row
[y
*cr
+n
-1] = usage
->col
[x
*cr
+n
-1] =
523 usage
->blk
[((y
%r
)*c
+(x
/r
))*cr
+n
-1] = TRUE
;
526 static int solver_elim(struct solver_usage
*usage
, int start
, int step
527 #ifdef STANDALONE_SOLVER
532 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
536 * Count the number of set bits within this section of the
541 for (i
= 0; i
< cr
; i
++)
542 if (usage
->cube
[start
+i
*step
]) {
556 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
]) {
557 #ifdef STANDALONE_SOLVER
558 if (solver_show_working
) {
560 printf("%*s", solver_recurse_depth
*4, "");
564 printf(":\n%*s placing %d at (%d,%d)\n",
565 solver_recurse_depth
*4, "", n
, 1+x
, 1+YUNTRANS(y
));
568 solver_place(usage
, x
, y
, n
);
572 #ifdef STANDALONE_SOLVER
573 if (solver_show_working
) {
575 printf("%*s", solver_recurse_depth
*4, "");
579 printf(":\n%*s no possibilities available\n",
580 solver_recurse_depth
*4, "");
589 static int solver_intersect(struct solver_usage
*usage
,
590 int start1
, int step1
, int start2
, int step2
591 #ifdef STANDALONE_SOLVER
596 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
600 * Loop over the first domain and see if there's any set bit
601 * not also in the second.
603 for (i
= 0; i
< cr
; i
++) {
604 int p
= start1
+i
*step1
;
605 if (usage
->cube
[p
] &&
606 !(p
>= start2
&& p
< start2
+cr
*step2
&&
607 (p
- start2
) % step2
== 0))
608 return 0; /* there is, so we can't deduce */
612 * We have determined that all set bits in the first domain are
613 * within its overlap with the second. So loop over the second
614 * domain and remove all set bits that aren't also in that
615 * overlap; return +1 iff we actually _did_ anything.
618 for (i
= 0; i
< cr
; i
++) {
619 int p
= start2
+i
*step2
;
620 if (usage
->cube
[p
] &&
621 !(p
>= start1
&& p
< start1
+cr
*step1
&& (p
- start1
) % step1
== 0))
623 #ifdef STANDALONE_SOLVER
624 if (solver_show_working
) {
629 printf("%*s", solver_recurse_depth
*4, "");
641 printf("%*s ruling out %d at (%d,%d)\n",
642 solver_recurse_depth
*4, "", pn
, 1+px
, 1+YUNTRANS(py
));
645 ret
= +1; /* we did something */
653 struct solver_scratch
{
654 unsigned char *grid
, *rowidx
, *colidx
, *set
;
658 static int solver_set(struct solver_usage
*usage
,
659 struct solver_scratch
*scratch
,
660 int start
, int step1
, int step2
661 #ifdef STANDALONE_SOLVER
666 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
668 unsigned char *grid
= scratch
->grid
;
669 unsigned char *rowidx
= scratch
->rowidx
;
670 unsigned char *colidx
= scratch
->colidx
;
671 unsigned char *set
= scratch
->set
;
674 * We are passed a cr-by-cr matrix of booleans. Our first job
675 * is to winnow it by finding any definite placements - i.e.
676 * any row with a solitary 1 - and discarding that row and the
677 * column containing the 1.
679 memset(rowidx
, TRUE
, cr
);
680 memset(colidx
, TRUE
, cr
);
681 for (i
= 0; i
< cr
; i
++) {
682 int count
= 0, first
= -1;
683 for (j
= 0; j
< cr
; j
++)
684 if (usage
->cube
[start
+i
*step1
+j
*step2
])
688 * If count == 0, then there's a row with no 1s at all and
689 * the puzzle is internally inconsistent. However, we ought
690 * to have caught this already during the simpler reasoning
691 * methods, so we can safely fail an assertion if we reach
696 rowidx
[i
] = colidx
[first
] = FALSE
;
700 * Convert each of rowidx/colidx from a list of 0s and 1s to a
701 * list of the indices of the 1s.
703 for (i
= j
= 0; i
< cr
; i
++)
707 for (i
= j
= 0; i
< cr
; i
++)
713 * And create the smaller matrix.
715 for (i
= 0; i
< n
; i
++)
716 for (j
= 0; j
< n
; j
++)
717 grid
[i
*cr
+j
] = usage
->cube
[start
+rowidx
[i
]*step1
+colidx
[j
]*step2
];
720 * Having done that, we now have a matrix in which every row
721 * has at least two 1s in. Now we search to see if we can find
722 * a rectangle of zeroes (in the set-theoretic sense of
723 * `rectangle', i.e. a subset of rows crossed with a subset of
724 * columns) whose width and height add up to n.
731 * We have a candidate set. If its size is <=1 or >=n-1
732 * then we move on immediately.
734 if (count
> 1 && count
< n
-1) {
736 * The number of rows we need is n-count. See if we can
737 * find that many rows which each have a zero in all
738 * the positions listed in `set'.
741 for (i
= 0; i
< n
; i
++) {
743 for (j
= 0; j
< n
; j
++)
744 if (set
[j
] && grid
[i
*cr
+j
]) {
753 * We expect never to be able to get _more_ than
754 * n-count suitable rows: this would imply that (for
755 * example) there are four numbers which between them
756 * have at most three possible positions, and hence it
757 * indicates a faulty deduction before this point or
760 if (rows
> n
- count
) {
761 #ifdef STANDALONE_SOLVER
762 if (solver_show_working
) {
764 printf("%*s", solver_recurse_depth
*4,
769 printf(":\n%*s contradiction reached\n",
770 solver_recurse_depth
*4, "");
776 if (rows
>= n
- count
) {
777 int progress
= FALSE
;
780 * We've got one! Now, for each row which _doesn't_
781 * satisfy the criterion, eliminate all its set
782 * bits in the positions _not_ listed in `set'.
783 * Return +1 (meaning progress has been made) if we
784 * successfully eliminated anything at all.
786 * This involves referring back through
787 * rowidx/colidx in order to work out which actual
788 * positions in the cube to meddle with.
790 for (i
= 0; i
< n
; i
++) {
792 for (j
= 0; j
< n
; j
++)
793 if (set
[j
] && grid
[i
*cr
+j
]) {
798 for (j
= 0; j
< n
; j
++)
799 if (!set
[j
] && grid
[i
*cr
+j
]) {
800 int fpos
= (start
+rowidx
[i
]*step1
+
802 #ifdef STANDALONE_SOLVER
803 if (solver_show_working
) {
808 printf("%*s", solver_recurse_depth
*4,
821 printf("%*s ruling out %d at (%d,%d)\n",
822 solver_recurse_depth
*4, "",
823 pn
, 1+px
, 1+YUNTRANS(py
));
827 usage
->cube
[fpos
] = FALSE
;
839 * Binary increment: change the rightmost 0 to a 1, and
840 * change all 1s to the right of it to 0s.
843 while (i
> 0 && set
[i
-1])
844 set
[--i
] = 0, count
--;
846 set
[--i
] = 1, count
++;
855 * Try to find a number in the possible set of (x1,y1) which can be
856 * ruled out because it would leave no possibilities for (x2,y2).
858 static int solver_mne(struct solver_usage
*usage
,
859 struct solver_scratch
*scratch
,
860 int x1
, int y1
, int x2
, int y2
)
862 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
864 unsigned char *set
= scratch
->set
;
865 unsigned char *numbers
= scratch
->rowidx
;
866 unsigned char *numbersleft
= scratch
->colidx
;
870 nb
[0] = scratch
->mne
;
871 nb
[1] = scratch
->mne
+ cr
;
874 * First, work out the mutual neighbour squares of the two. We
875 * can assert that they're not actually in the same block,
876 * which leaves two possibilities: they're in different block
877 * rows _and_ different block columns (thus their mutual
878 * neighbours are precisely the other two corners of the
879 * rectangle), or they're in the same row (WLOG) and different
880 * columns, in which case their mutual neighbours are the
881 * column of each block aligned with the other square.
883 * We divide the mutual neighbours into two separate subsets
884 * nb[0] and nb[1]; squares in the same subset are not only
885 * adjacent to both our key squares, but are also always
886 * adjacent to one another.
888 if (x1
/ r
!= x2
/ r
&& y1
% r
!= y2
% r
) {
889 /* Corners of the rectangle. */
891 nb
[0][0] = cubepos(x2
, y1
, 1);
892 nb
[1][0] = cubepos(x1
, y2
, 1);
893 } else if (x1
/ r
!= x2
/ r
) {
894 /* Same row of blocks; different blocks within that row. */
895 int x1b
= x1
- (x1
% r
);
896 int x2b
= x2
- (x2
% r
);
899 for (i
= 0; i
< r
; i
++) {
900 nb
[0][i
] = cubepos(x2b
+i
, y1
, 1);
901 nb
[1][i
] = cubepos(x1b
+i
, y2
, 1);
904 /* Same column of blocks; different blocks within that column. */
908 assert(y1
% r
!= y2
% r
);
911 for (i
= 0; i
< c
; i
++) {
912 nb
[0][i
] = cubepos(x2
, y1b
+i
*r
, 1);
913 nb
[1][i
] = cubepos(x1
, y2b
+i
*r
, 1);
918 * Right. Now loop over each possible number.
920 for (n
= 1; n
<= cr
; n
++) {
921 if (!cube(x1
, y1
, n
))
923 for (j
= 0; j
< cr
; j
++)
924 numbersleft
[j
] = cube(x2
, y2
, j
+1);
927 * Go over every possible subset of each neighbour list,
928 * and see if its union of possible numbers minus n has the
929 * same size as the subset. If so, add the numbers in that
930 * subset to the set of things which would be ruled out
931 * from (x2,y2) if n were placed at (x1,y1).
937 * Binary increment: change the rightmost 0 to a 1, and
938 * change all 1s to the right of it to 0s.
941 while (i
> 0 && set
[i
-1])
942 set
[--i
] = 0, count
--;
944 set
[--i
] = 1, count
++;
949 * Examine this subset of each neighbour set.
951 for (nbi
= 0; nbi
< 2; nbi
++) {
954 memset(numbers
, 0, cr
);
956 for (i
= 0; i
< nnb
; i
++)
958 for (j
= 0; j
< cr
; j
++)
959 if (j
!= n
-1 && usage
->cube
[nbs
[i
] + j
])
962 for (i
= j
= 0; j
< cr
; j
++)
967 * Got one. This subset of nbs, in the absence
968 * of n, would definitely contain all the
969 * numbers listed in `numbers'. Rule them out
972 for (j
= 0; j
< cr
; j
++)
980 * If we've got nothing left in `numbersleft', we have a
981 * successful mutual neighbour elimination.
983 for (j
= 0; j
< cr
; j
++)
988 #ifdef STANDALONE_SOLVER
989 if (solver_show_working
) {
990 printf("%*smutual neighbour elimination, (%d,%d) vs (%d,%d):\n",
991 solver_recurse_depth
*4, "",
992 1+x1
, 1+YUNTRANS(y1
), 1+x2
, 1+YUNTRANS(y2
));
993 printf("%*s ruling out %d at (%d,%d)\n",
994 solver_recurse_depth
*4, "",
995 n
, 1+x1
, 1+YUNTRANS(y1
));
998 cube(x1
, y1
, n
) = FALSE
;
1003 return 0; /* nothing found */
1006 static struct solver_scratch
*solver_new_scratch(struct solver_usage
*usage
)
1008 struct solver_scratch
*scratch
= snew(struct solver_scratch
);
1010 scratch
->grid
= snewn(cr
*cr
, unsigned char);
1011 scratch
->rowidx
= snewn(cr
, unsigned char);
1012 scratch
->colidx
= snewn(cr
, unsigned char);
1013 scratch
->set
= snewn(cr
, unsigned char);
1014 scratch
->mne
= snewn(2*cr
, int);
1018 static void solver_free_scratch(struct solver_scratch
*scratch
)
1020 sfree(scratch
->mne
);
1021 sfree(scratch
->set
);
1022 sfree(scratch
->colidx
);
1023 sfree(scratch
->rowidx
);
1024 sfree(scratch
->grid
);
1028 static int solver(int c
, int r
, digit
*grid
, int maxdiff
)
1030 struct solver_usage
*usage
;
1031 struct solver_scratch
*scratch
;
1033 int x
, y
, x2
, y2
, n
, ret
;
1034 int diff
= DIFF_BLOCK
;
1037 * Set up a usage structure as a clean slate (everything
1040 usage
= snew(struct solver_usage
);
1044 usage
->cube
= snewn(cr
*cr
*cr
, unsigned char);
1045 usage
->grid
= grid
; /* write straight back to the input */
1046 memset(usage
->cube
, TRUE
, cr
*cr
*cr
);
1048 usage
->row
= snewn(cr
* cr
, unsigned char);
1049 usage
->col
= snewn(cr
* cr
, unsigned char);
1050 usage
->blk
= snewn(cr
* cr
, unsigned char);
1051 memset(usage
->row
, FALSE
, cr
* cr
);
1052 memset(usage
->col
, FALSE
, cr
* cr
);
1053 memset(usage
->blk
, FALSE
, cr
* cr
);
1055 scratch
= solver_new_scratch(usage
);
1058 * Place all the clue numbers we are given.
1060 for (x
= 0; x
< cr
; x
++)
1061 for (y
= 0; y
< cr
; y
++)
1063 solver_place(usage
, x
, YTRANS(y
), grid
[y
*cr
+x
]);
1066 * Now loop over the grid repeatedly trying all permitted modes
1067 * of reasoning. The loop terminates if we complete an
1068 * iteration without making any progress; we then return
1069 * failure or success depending on whether the grid is full or
1074 * I'd like to write `continue;' inside each of the
1075 * following loops, so that the solver returns here after
1076 * making some progress. However, I can't specify that I
1077 * want to continue an outer loop rather than the innermost
1078 * one, so I'm apologetically resorting to a goto.
1083 * Blockwise positional elimination.
1085 for (x
= 0; x
< cr
; x
+= r
)
1086 for (y
= 0; y
< r
; y
++)
1087 for (n
= 1; n
<= cr
; n
++)
1088 if (!usage
->blk
[(y
*c
+(x
/r
))*cr
+n
-1]) {
1089 ret
= solver_elim(usage
, cubepos(x
,y
,n
), r
*cr
1090 #ifdef STANDALONE_SOLVER
1091 , "positional elimination,"
1092 " %d in block (%d,%d)", n
, 1+x
/r
, 1+y
1096 diff
= DIFF_IMPOSSIBLE
;
1098 } else if (ret
> 0) {
1099 diff
= max(diff
, DIFF_BLOCK
);
1104 if (maxdiff
<= DIFF_BLOCK
)
1108 * Row-wise positional elimination.
1110 for (y
= 0; y
< cr
; y
++)
1111 for (n
= 1; n
<= cr
; n
++)
1112 if (!usage
->row
[y
*cr
+n
-1]) {
1113 ret
= solver_elim(usage
, cubepos(0,y
,n
), cr
*cr
1114 #ifdef STANDALONE_SOLVER
1115 , "positional elimination,"
1116 " %d in row %d", n
, 1+YUNTRANS(y
)
1120 diff
= DIFF_IMPOSSIBLE
;
1122 } else if (ret
> 0) {
1123 diff
= max(diff
, DIFF_SIMPLE
);
1128 * Column-wise positional elimination.
1130 for (x
= 0; x
< cr
; x
++)
1131 for (n
= 1; n
<= cr
; n
++)
1132 if (!usage
->col
[x
*cr
+n
-1]) {
1133 ret
= solver_elim(usage
, cubepos(x
,0,n
), cr
1134 #ifdef STANDALONE_SOLVER
1135 , "positional elimination,"
1136 " %d in column %d", n
, 1+x
1140 diff
= DIFF_IMPOSSIBLE
;
1142 } else if (ret
> 0) {
1143 diff
= max(diff
, DIFF_SIMPLE
);
1149 * Numeric elimination.
1151 for (x
= 0; x
< cr
; x
++)
1152 for (y
= 0; y
< cr
; y
++)
1153 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
]) {
1154 ret
= solver_elim(usage
, cubepos(x
,y
,1), 1
1155 #ifdef STANDALONE_SOLVER
1156 , "numeric elimination at (%d,%d)", 1+x
,
1161 diff
= DIFF_IMPOSSIBLE
;
1163 } else if (ret
> 0) {
1164 diff
= max(diff
, DIFF_SIMPLE
);
1169 if (maxdiff
<= DIFF_SIMPLE
)
1173 * Intersectional analysis, rows vs blocks.
1175 for (y
= 0; y
< cr
; y
++)
1176 for (x
= 0; x
< cr
; x
+= r
)
1177 for (n
= 1; n
<= cr
; n
++)
1179 * solver_intersect() never returns -1.
1181 if (!usage
->row
[y
*cr
+n
-1] &&
1182 !usage
->blk
[((y
%r
)*c
+(x
/r
))*cr
+n
-1] &&
1183 (solver_intersect(usage
, cubepos(0,y
,n
), cr
*cr
,
1184 cubepos(x
,y
%r
,n
), r
*cr
1185 #ifdef STANDALONE_SOLVER
1186 , "intersectional analysis,"
1187 " %d in row %d vs block (%d,%d)",
1188 n
, 1+YUNTRANS(y
), 1+x
/r
, 1+y
%r
1191 solver_intersect(usage
, cubepos(x
,y
%r
,n
), r
*cr
,
1192 cubepos(0,y
,n
), cr
*cr
1193 #ifdef STANDALONE_SOLVER
1194 , "intersectional analysis,"
1195 " %d in block (%d,%d) vs row %d",
1196 n
, 1+x
/r
, 1+y
%r
, 1+YUNTRANS(y
)
1199 diff
= max(diff
, DIFF_INTERSECT
);
1204 * Intersectional analysis, columns vs blocks.
1206 for (x
= 0; x
< cr
; x
++)
1207 for (y
= 0; y
< r
; y
++)
1208 for (n
= 1; n
<= cr
; n
++)
1209 if (!usage
->col
[x
*cr
+n
-1] &&
1210 !usage
->blk
[(y
*c
+(x
/r
))*cr
+n
-1] &&
1211 (solver_intersect(usage
, cubepos(x
,0,n
), cr
,
1212 cubepos((x
/r
)*r
,y
,n
), r
*cr
1213 #ifdef STANDALONE_SOLVER
1214 , "intersectional analysis,"
1215 " %d in column %d vs block (%d,%d)",
1219 solver_intersect(usage
, cubepos((x
/r
)*r
,y
,n
), r
*cr
,
1221 #ifdef STANDALONE_SOLVER
1222 , "intersectional analysis,"
1223 " %d in block (%d,%d) vs column %d",
1227 diff
= max(diff
, DIFF_INTERSECT
);
1231 if (maxdiff
<= DIFF_INTERSECT
)
1235 * Blockwise set elimination.
1237 for (x
= 0; x
< cr
; x
+= r
)
1238 for (y
= 0; y
< r
; y
++) {
1239 ret
= solver_set(usage
, scratch
, cubepos(x
,y
,1), r
*cr
, 1
1240 #ifdef STANDALONE_SOLVER
1241 , "set elimination, block (%d,%d)", 1+x
/r
, 1+y
1245 diff
= DIFF_IMPOSSIBLE
;
1247 } else if (ret
> 0) {
1248 diff
= max(diff
, DIFF_SET
);
1254 * Row-wise set elimination.
1256 for (y
= 0; y
< cr
; y
++) {
1257 ret
= solver_set(usage
, scratch
, cubepos(0,y
,1), cr
*cr
, 1
1258 #ifdef STANDALONE_SOLVER
1259 , "set elimination, row %d", 1+YUNTRANS(y
)
1263 diff
= DIFF_IMPOSSIBLE
;
1265 } else if (ret
> 0) {
1266 diff
= max(diff
, DIFF_SET
);
1272 * Column-wise set elimination.
1274 for (x
= 0; x
< cr
; x
++) {
1275 ret
= solver_set(usage
, scratch
, cubepos(x
,0,1), cr
, 1
1276 #ifdef STANDALONE_SOLVER
1277 , "set elimination, column %d", 1+x
1281 diff
= DIFF_IMPOSSIBLE
;
1283 } else if (ret
> 0) {
1284 diff
= max(diff
, DIFF_SET
);
1290 * Mutual neighbour elimination.
1292 for (y
= 0; y
+1 < cr
; y
++) {
1293 for (x
= 0; x
+1 < cr
; x
++) {
1294 for (y2
= y
+1; y2
< cr
; y2
++) {
1295 for (x2
= x
+1; x2
< cr
; x2
++) {
1297 * Can't do mutual neighbour elimination
1298 * between elements of the same actual
1301 if (x
/r
== x2
/r
&& y
%r
== y2
%r
)
1305 * Otherwise, try (x,y) vs (x2,y2) in both
1306 * directions, and likewise (x2,y) vs
1309 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
] &&
1310 !usage
->grid
[YUNTRANS(y2
)*cr
+x2
] &&
1311 (solver_mne(usage
, scratch
, x
, y
, x2
, y2
) ||
1312 solver_mne(usage
, scratch
, x2
, y2
, x
, y
))) {
1313 diff
= max(diff
, DIFF_NEIGHBOUR
);
1316 if (!usage
->grid
[YUNTRANS(y
)*cr
+x2
] &&
1317 !usage
->grid
[YUNTRANS(y2
)*cr
+x
] &&
1318 (solver_mne(usage
, scratch
, x2
, y
, x
, y2
) ||
1319 solver_mne(usage
, scratch
, x
, y2
, x2
, y
))) {
1320 diff
= max(diff
, DIFF_NEIGHBOUR
);
1329 * If we reach here, we have made no deductions in this
1330 * iteration, so the algorithm terminates.
1336 * Last chance: if we haven't fully solved the puzzle yet, try
1337 * recursing based on guesses for a particular square. We pick
1338 * one of the most constrained empty squares we can find, which
1339 * has the effect of pruning the search tree as much as
1342 if (maxdiff
>= DIFF_RECURSIVE
) {
1343 int best
, bestcount
;
1348 for (y
= 0; y
< cr
; y
++)
1349 for (x
= 0; x
< cr
; x
++)
1350 if (!grid
[y
*cr
+x
]) {
1354 * An unfilled square. Count the number of
1355 * possible digits in it.
1358 for (n
= 1; n
<= cr
; n
++)
1359 if (cube(x
,YTRANS(y
),n
))
1363 * We should have found any impossibilities
1364 * already, so this can safely be an assert.
1368 if (count
< bestcount
) {
1376 digit
*list
, *ingrid
, *outgrid
;
1378 diff
= DIFF_IMPOSSIBLE
; /* no solution found yet */
1381 * Attempt recursion.
1386 list
= snewn(cr
, digit
);
1387 ingrid
= snewn(cr
* cr
, digit
);
1388 outgrid
= snewn(cr
* cr
, digit
);
1389 memcpy(ingrid
, grid
, cr
* cr
);
1391 /* Make a list of the possible digits. */
1392 for (j
= 0, n
= 1; n
<= cr
; n
++)
1393 if (cube(x
,YTRANS(y
),n
))
1396 #ifdef STANDALONE_SOLVER
1397 if (solver_show_working
) {
1399 printf("%*srecursing on (%d,%d) [",
1400 solver_recurse_depth
*4, "", x
, y
);
1401 for (i
= 0; i
< j
; i
++) {
1402 printf("%s%d", sep
, list
[i
]);
1410 * And step along the list, recursing back into the
1411 * main solver at every stage.
1413 for (i
= 0; i
< j
; i
++) {
1416 memcpy(outgrid
, ingrid
, cr
* cr
);
1417 outgrid
[y
*cr
+x
] = list
[i
];
1419 #ifdef STANDALONE_SOLVER
1420 if (solver_show_working
)
1421 printf("%*sguessing %d at (%d,%d)\n",
1422 solver_recurse_depth
*4, "", list
[i
], x
, y
);
1423 solver_recurse_depth
++;
1426 ret
= solver(c
, r
, outgrid
, maxdiff
);
1428 #ifdef STANDALONE_SOLVER
1429 solver_recurse_depth
--;
1430 if (solver_show_working
) {
1431 printf("%*sretracting %d at (%d,%d)\n",
1432 solver_recurse_depth
*4, "", list
[i
], x
, y
);
1437 * If we have our first solution, copy it into the
1438 * grid we will return.
1440 if (diff
== DIFF_IMPOSSIBLE
&& ret
!= DIFF_IMPOSSIBLE
)
1441 memcpy(grid
, outgrid
, cr
*cr
);
1443 if (ret
== DIFF_AMBIGUOUS
)
1444 diff
= DIFF_AMBIGUOUS
;
1445 else if (ret
== DIFF_IMPOSSIBLE
)
1446 /* do not change our return value */;
1448 /* the recursion turned up exactly one solution */
1449 if (diff
== DIFF_IMPOSSIBLE
)
1450 diff
= DIFF_RECURSIVE
;
1452 diff
= DIFF_AMBIGUOUS
;
1456 * As soon as we've found more than one solution,
1457 * give up immediately.
1459 if (diff
== DIFF_AMBIGUOUS
)
1470 * We're forbidden to use recursion, so we just see whether
1471 * our grid is fully solved, and return DIFF_IMPOSSIBLE
1474 for (y
= 0; y
< cr
; y
++)
1475 for (x
= 0; x
< cr
; x
++)
1477 diff
= DIFF_IMPOSSIBLE
;
1482 #ifdef STANDALONE_SOLVER
1483 if (solver_show_working
)
1484 printf("%*s%s found\n",
1485 solver_recurse_depth
*4, "",
1486 diff
== DIFF_IMPOSSIBLE ?
"no solution" :
1487 diff
== DIFF_AMBIGUOUS ?
"multiple solutions" :
1497 solver_free_scratch(scratch
);
1502 /* ----------------------------------------------------------------------
1503 * End of solver code.
1506 /* ----------------------------------------------------------------------
1507 * Solo filled-grid generator.
1509 * This grid generator works by essentially trying to solve a grid
1510 * starting from no clues, and not worrying that there's more than
1511 * one possible solution. Unfortunately, it isn't computationally
1512 * feasible to do this by calling the above solver with an empty
1513 * grid, because that one needs to allocate a lot of scratch space
1514 * at every recursion level. Instead, I have a much simpler
1515 * algorithm which I shamelessly copied from a Python solver
1516 * written by Andrew Wilkinson (which is GPLed, but I've reused
1517 * only ideas and no code). It mostly just does the obvious
1518 * recursive thing: pick an empty square, put one of the possible
1519 * digits in it, recurse until all squares are filled, backtrack
1520 * and change some choices if necessary.
1522 * The clever bit is that every time it chooses which square to
1523 * fill in next, it does so by counting the number of _possible_
1524 * numbers that can go in each square, and it prioritises so that
1525 * it picks a square with the _lowest_ number of possibilities. The
1526 * idea is that filling in lots of the obvious bits (particularly
1527 * any squares with only one possibility) will cut down on the list
1528 * of possibilities for other squares and hence reduce the enormous
1529 * search space as much as possible as early as possible.
1533 * Internal data structure used in gridgen to keep track of
1536 struct gridgen_coord
{ int x
, y
, r
; };
1537 struct gridgen_usage
{
1538 int c
, r
, cr
; /* cr == c*r */
1539 /* grid is a copy of the input grid, modified as we go along */
1541 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
1543 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
1545 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
1547 /* This lists all the empty spaces remaining in the grid. */
1548 struct gridgen_coord
*spaces
;
1550 /* If we need randomisation in the solve, this is our random state. */
1555 * The real recursive step in the generating function.
1557 static int gridgen_real(struct gridgen_usage
*usage
, digit
*grid
)
1559 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
1560 int i
, j
, n
, sx
, sy
, bestm
, bestr
, ret
;
1564 * Firstly, check for completion! If there are no spaces left
1565 * in the grid, we have a solution.
1567 if (usage
->nspaces
== 0) {
1568 memcpy(grid
, usage
->grid
, cr
* cr
);
1573 * Otherwise, there must be at least one space. Find the most
1574 * constrained space, using the `r' field as a tie-breaker.
1576 bestm
= cr
+1; /* so that any space will beat it */
1579 for (j
= 0; j
< usage
->nspaces
; j
++) {
1580 int x
= usage
->spaces
[j
].x
, y
= usage
->spaces
[j
].y
;
1584 * Find the number of digits that could go in this space.
1587 for (n
= 0; n
< cr
; n
++)
1588 if (!usage
->row
[y
*cr
+n
] && !usage
->col
[x
*cr
+n
] &&
1589 !usage
->blk
[((y
/c
)*c
+(x
/r
))*cr
+n
])
1592 if (m
< bestm
|| (m
== bestm
&& usage
->spaces
[j
].r
< bestr
)) {
1594 bestr
= usage
->spaces
[j
].r
;
1602 * Swap that square into the final place in the spaces array,
1603 * so that decrementing nspaces will remove it from the list.
1605 if (i
!= usage
->nspaces
-1) {
1606 struct gridgen_coord t
;
1607 t
= usage
->spaces
[usage
->nspaces
-1];
1608 usage
->spaces
[usage
->nspaces
-1] = usage
->spaces
[i
];
1609 usage
->spaces
[i
] = t
;
1613 * Now we've decided which square to start our recursion at,
1614 * simply go through all possible values, shuffling them
1615 * randomly first if necessary.
1617 digits
= snewn(bestm
, int);
1619 for (n
= 0; n
< cr
; n
++)
1620 if (!usage
->row
[sy
*cr
+n
] && !usage
->col
[sx
*cr
+n
] &&
1621 !usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
]) {
1626 shuffle(digits
, j
, sizeof(*digits
), usage
->rs
);
1628 /* And finally, go through the digit list and actually recurse. */
1630 for (i
= 0; i
< j
; i
++) {
1633 /* Update the usage structure to reflect the placing of this digit. */
1634 usage
->row
[sy
*cr
+n
-1] = usage
->col
[sx
*cr
+n
-1] =
1635 usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
-1] = TRUE
;
1636 usage
->grid
[sy
*cr
+sx
] = n
;
1639 /* Call the solver recursively. Stop when we find a solution. */
1640 if (gridgen_real(usage
, grid
))
1643 /* Revert the usage structure. */
1644 usage
->row
[sy
*cr
+n
-1] = usage
->col
[sx
*cr
+n
-1] =
1645 usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
-1] = FALSE
;
1646 usage
->grid
[sy
*cr
+sx
] = 0;
1658 * Entry point to generator. You give it dimensions and a starting
1659 * grid, which is simply an array of cr*cr digits.
1661 static void gridgen(int c
, int r
, digit
*grid
, random_state
*rs
)
1663 struct gridgen_usage
*usage
;
1667 * Clear the grid to start with.
1669 memset(grid
, 0, cr
*cr
);
1672 * Create a gridgen_usage structure.
1674 usage
= snew(struct gridgen_usage
);
1680 usage
->grid
= snewn(cr
* cr
, digit
);
1681 memcpy(usage
->grid
, grid
, cr
* cr
);
1683 usage
->row
= snewn(cr
* cr
, unsigned char);
1684 usage
->col
= snewn(cr
* cr
, unsigned char);
1685 usage
->blk
= snewn(cr
* cr
, unsigned char);
1686 memset(usage
->row
, FALSE
, cr
* cr
);
1687 memset(usage
->col
, FALSE
, cr
* cr
);
1688 memset(usage
->blk
, FALSE
, cr
* cr
);
1690 usage
->spaces
= snewn(cr
* cr
, struct gridgen_coord
);
1696 * Initialise the list of grid spaces.
1698 for (y
= 0; y
< cr
; y
++) {
1699 for (x
= 0; x
< cr
; x
++) {
1700 usage
->spaces
[usage
->nspaces
].x
= x
;
1701 usage
->spaces
[usage
->nspaces
].y
= y
;
1702 usage
->spaces
[usage
->nspaces
].r
= random_bits(rs
, 31);
1708 * Run the real generator function.
1710 gridgen_real(usage
, grid
);
1713 * Clean up the usage structure now we have our answer.
1715 sfree(usage
->spaces
);
1723 /* ----------------------------------------------------------------------
1724 * End of grid generator code.
1728 * Check whether a grid contains a valid complete puzzle.
1730 static int check_valid(int c
, int r
, digit
*grid
)
1733 unsigned char *used
;
1736 used
= snewn(cr
, unsigned char);
1739 * Check that each row contains precisely one of everything.
1741 for (y
= 0; y
< cr
; y
++) {
1742 memset(used
, FALSE
, cr
);
1743 for (x
= 0; x
< cr
; x
++)
1744 if (grid
[y
*cr
+x
] > 0 && grid
[y
*cr
+x
] <= cr
)
1745 used
[grid
[y
*cr
+x
]-1] = TRUE
;
1746 for (n
= 0; n
< cr
; n
++)
1754 * Check that each column contains precisely one of everything.
1756 for (x
= 0; x
< cr
; x
++) {
1757 memset(used
, FALSE
, cr
);
1758 for (y
= 0; y
< cr
; y
++)
1759 if (grid
[y
*cr
+x
] > 0 && grid
[y
*cr
+x
] <= cr
)
1760 used
[grid
[y
*cr
+x
]-1] = TRUE
;
1761 for (n
= 0; n
< cr
; n
++)
1769 * Check that each block contains precisely one of everything.
1771 for (x
= 0; x
< cr
; x
+= r
) {
1772 for (y
= 0; y
< cr
; y
+= c
) {
1774 memset(used
, FALSE
, cr
);
1775 for (xx
= x
; xx
< x
+r
; xx
++)
1776 for (yy
= 0; yy
< y
+c
; yy
++)
1777 if (grid
[yy
*cr
+xx
] > 0 && grid
[yy
*cr
+xx
] <= cr
)
1778 used
[grid
[yy
*cr
+xx
]-1] = TRUE
;
1779 for (n
= 0; n
< cr
; n
++)
1791 static int symmetries(game_params
*params
, int x
, int y
, int *output
, int s
)
1793 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1796 #define ADD(x,y) (*output++ = (x), *output++ = (y), i++)
1802 break; /* just x,y is all we need */
1804 ADD(cr
- 1 - x
, cr
- 1 - y
);
1809 ADD(cr
- 1 - x
, cr
- 1 - y
);
1820 ADD(cr
- 1 - x
, cr
- 1 - y
);
1824 ADD(cr
- 1 - x
, cr
- 1 - y
);
1825 ADD(cr
- 1 - y
, cr
- 1 - x
);
1830 ADD(cr
- 1 - x
, cr
- 1 - y
);
1834 ADD(cr
- 1 - y
, cr
- 1 - x
);
1843 static char *encode_solve_move(int cr
, digit
*grid
)
1846 char *ret
, *p
, *sep
;
1849 * It's surprisingly easy to work out _exactly_ how long this
1850 * string needs to be. To decimal-encode all the numbers from 1
1853 * - every number has a units digit; total is n.
1854 * - all numbers above 9 have a tens digit; total is max(n-9,0).
1855 * - all numbers above 99 have a hundreds digit; total is max(n-99,0).
1859 for (i
= 1; i
<= cr
; i
*= 10)
1860 len
+= max(cr
- i
+ 1, 0);
1861 len
+= cr
; /* don't forget the commas */
1862 len
*= cr
; /* there are cr rows of these */
1865 * Now len is one bigger than the total size of the
1866 * comma-separated numbers (because we counted an
1867 * additional leading comma). We need to have a leading S
1868 * and a trailing NUL, so we're off by one in total.
1872 ret
= snewn(len
, char);
1876 for (i
= 0; i
< cr
*cr
; i
++) {
1877 p
+= sprintf(p
, "%s%d", sep
, grid
[i
]);
1881 assert(p
- ret
== len
);
1886 static char *new_game_desc(game_params
*params
, random_state
*rs
,
1887 char **aux
, int interactive
)
1889 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1891 digit
*grid
, *grid2
;
1892 struct xy
{ int x
, y
; } *locs
;
1895 int coords
[16], ncoords
;
1900 * Adjust the maximum difficulty level to be consistent with
1901 * the puzzle size: all 2x2 puzzles appear to be Trivial
1902 * (DIFF_BLOCK) so we cannot hold out for even a Basic
1903 * (DIFF_SIMPLE) one.
1905 maxdiff
= params
->diff
;
1906 if (c
== 2 && r
== 2)
1907 maxdiff
= DIFF_BLOCK
;
1909 grid
= snewn(area
, digit
);
1910 locs
= snewn(area
, struct xy
);
1911 grid2
= snewn(area
, digit
);
1914 * Loop until we get a grid of the required difficulty. This is
1915 * nasty, but it seems to be unpleasantly hard to generate
1916 * difficult grids otherwise.
1920 * Generate a random solved state.
1922 gridgen(c
, r
, grid
, rs
);
1923 assert(check_valid(c
, r
, grid
));
1926 * Save the solved grid in aux.
1930 * We might already have written *aux the last time we
1931 * went round this loop, in which case we should free
1932 * the old aux before overwriting it with the new one.
1938 *aux
= encode_solve_move(cr
, grid
);
1942 * Now we have a solved grid, start removing things from it
1943 * while preserving solubility.
1947 * Find the set of equivalence classes of squares permitted
1948 * by the selected symmetry. We do this by enumerating all
1949 * the grid squares which have no symmetric companion
1950 * sorting lower than themselves.
1953 for (y
= 0; y
< cr
; y
++)
1954 for (x
= 0; x
< cr
; x
++) {
1958 ncoords
= symmetries(params
, x
, y
, coords
, params
->symm
);
1959 for (j
= 0; j
< ncoords
; j
++)
1960 if (coords
[2*j
+1]*cr
+coords
[2*j
] < i
)
1970 * Now shuffle that list.
1972 shuffle(locs
, nlocs
, sizeof(*locs
), rs
);
1975 * Now loop over the shuffled list and, for each element,
1976 * see whether removing that element (and its reflections)
1977 * from the grid will still leave the grid soluble.
1979 for (i
= 0; i
< nlocs
; i
++) {
1985 memcpy(grid2
, grid
, area
);
1986 ncoords
= symmetries(params
, x
, y
, coords
, params
->symm
);
1987 for (j
= 0; j
< ncoords
; j
++)
1988 grid2
[coords
[2*j
+1]*cr
+coords
[2*j
]] = 0;
1990 ret
= solver(c
, r
, grid2
, maxdiff
);
1991 if (ret
!= DIFF_IMPOSSIBLE
&& ret
!= DIFF_AMBIGUOUS
) {
1992 for (j
= 0; j
< ncoords
; j
++)
1993 grid
[coords
[2*j
+1]*cr
+coords
[2*j
]] = 0;
1997 memcpy(grid2
, grid
, area
);
1998 } while (solver(c
, r
, grid2
, maxdiff
) < maxdiff
);
2004 * Now we have the grid as it will be presented to the user.
2005 * Encode it in a game desc.
2011 desc
= snewn(5 * area
, char);
2014 for (i
= 0; i
<= area
; i
++) {
2015 int n
= (i
< area ? grid
[i
] : -1);
2022 int c
= 'a' - 1 + run
;
2026 run
-= c
- ('a' - 1);
2030 * If there's a number in the very top left or
2031 * bottom right, there's no point putting an
2032 * unnecessary _ before or after it.
2034 if (p
> desc
&& n
> 0)
2038 p
+= sprintf(p
, "%d", n
);
2042 assert(p
- desc
< 5 * area
);
2044 desc
= sresize(desc
, p
- desc
, char);
2052 static char *validate_desc(game_params
*params
, char *desc
)
2054 int area
= params
->r
* params
->r
* params
->c
* params
->c
;
2059 if (n
>= 'a' && n
<= 'z') {
2060 squares
+= n
- 'a' + 1;
2061 } else if (n
== '_') {
2063 } else if (n
> '0' && n
<= '9') {
2065 while (*desc
>= '0' && *desc
<= '9')
2068 return "Invalid character in game description";
2072 return "Not enough data to fill grid";
2075 return "Too much data to fit in grid";
2080 static game_state
*new_game(midend
*me
, game_params
*params
, char *desc
)
2082 game_state
*state
= snew(game_state
);
2083 int c
= params
->c
, r
= params
->r
, cr
= c
*r
, area
= cr
* cr
;
2086 state
->c
= params
->c
;
2087 state
->r
= params
->r
;
2089 state
->grid
= snewn(area
, digit
);
2090 state
->pencil
= snewn(area
* cr
, unsigned char);
2091 memset(state
->pencil
, 0, area
* cr
);
2092 state
->immutable
= snewn(area
, unsigned char);
2093 memset(state
->immutable
, FALSE
, area
);
2095 state
->completed
= state
->cheated
= FALSE
;
2100 if (n
>= 'a' && n
<= 'z') {
2101 int run
= n
- 'a' + 1;
2102 assert(i
+ run
<= area
);
2104 state
->grid
[i
++] = 0;
2105 } else if (n
== '_') {
2107 } else if (n
> '0' && n
<= '9') {
2109 state
->immutable
[i
] = TRUE
;
2110 state
->grid
[i
++] = atoi(desc
-1);
2111 while (*desc
>= '0' && *desc
<= '9')
2114 assert(!"We can't get here");
2122 static game_state
*dup_game(game_state
*state
)
2124 game_state
*ret
= snew(game_state
);
2125 int c
= state
->c
, r
= state
->r
, cr
= c
*r
, area
= cr
* cr
;
2130 ret
->grid
= snewn(area
, digit
);
2131 memcpy(ret
->grid
, state
->grid
, area
);
2133 ret
->pencil
= snewn(area
* cr
, unsigned char);
2134 memcpy(ret
->pencil
, state
->pencil
, area
* cr
);
2136 ret
->immutable
= snewn(area
, unsigned char);
2137 memcpy(ret
->immutable
, state
->immutable
, area
);
2139 ret
->completed
= state
->completed
;
2140 ret
->cheated
= state
->cheated
;
2145 static void free_game(game_state
*state
)
2147 sfree(state
->immutable
);
2148 sfree(state
->pencil
);
2153 static char *solve_game(game_state
*state
, game_state
*currstate
,
2154 char *ai
, char **error
)
2156 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
2162 * If we already have the solution in ai, save ourselves some
2168 grid
= snewn(cr
*cr
, digit
);
2169 memcpy(grid
, state
->grid
, cr
*cr
);
2170 solve_ret
= solver(c
, r
, grid
, DIFF_RECURSIVE
);
2174 if (solve_ret
== DIFF_IMPOSSIBLE
)
2175 *error
= "No solution exists for this puzzle";
2176 else if (solve_ret
== DIFF_AMBIGUOUS
)
2177 *error
= "Multiple solutions exist for this puzzle";
2184 ret
= encode_solve_move(cr
, grid
);
2191 static char *grid_text_format(int c
, int r
, digit
*grid
)
2199 * There are cr lines of digits, plus r-1 lines of block
2200 * separators. Each line contains cr digits, cr-1 separating
2201 * spaces, and c-1 two-character block separators. Thus, the
2202 * total length of a line is 2*cr+2*c-3 (not counting the
2203 * newline), and there are cr+r-1 of them.
2205 maxlen
= (cr
+r
-1) * (2*cr
+2*c
-2);
2206 ret
= snewn(maxlen
+1, char);
2209 for (y
= 0; y
< cr
; y
++) {
2210 for (x
= 0; x
< cr
; x
++) {
2211 int ch
= grid
[y
* cr
+ x
];
2221 if ((x
+1) % r
== 0) {
2228 if (y
+1 < cr
&& (y
+1) % c
== 0) {
2229 for (x
= 0; x
< cr
; x
++) {
2233 if ((x
+1) % r
== 0) {
2243 assert(p
- ret
== maxlen
);
2248 static char *game_text_format(game_state
*state
)
2250 return grid_text_format(state
->c
, state
->r
, state
->grid
);
2255 * These are the coordinates of the currently highlighted
2256 * square on the grid, or -1,-1 if there isn't one. When there
2257 * is, pressing a valid number or letter key or Space will
2258 * enter that number or letter in the grid.
2262 * This indicates whether the current highlight is a
2263 * pencil-mark one or a real one.
2268 static game_ui
*new_ui(game_state
*state
)
2270 game_ui
*ui
= snew(game_ui
);
2272 ui
->hx
= ui
->hy
= -1;
2278 static void free_ui(game_ui
*ui
)
2283 static char *encode_ui(game_ui
*ui
)
2288 static void decode_ui(game_ui
*ui
, char *encoding
)
2292 static void game_changed_state(game_ui
*ui
, game_state
*oldstate
,
2293 game_state
*newstate
)
2295 int c
= newstate
->c
, r
= newstate
->r
, cr
= c
*r
;
2297 * We prevent pencil-mode highlighting of a filled square. So
2298 * if the user has just filled in a square which we had a
2299 * pencil-mode highlight in (by Undo, or by Redo, or by Solve),
2300 * then we cancel the highlight.
2302 if (ui
->hx
>= 0 && ui
->hy
>= 0 && ui
->hpencil
&&
2303 newstate
->grid
[ui
->hy
* cr
+ ui
->hx
] != 0) {
2304 ui
->hx
= ui
->hy
= -1;
2308 struct game_drawstate
{
2313 unsigned char *pencil
;
2315 /* This is scratch space used within a single call to game_redraw. */
2319 static char *interpret_move(game_state
*state
, game_ui
*ui
, game_drawstate
*ds
,
2320 int x
, int y
, int button
)
2322 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
2326 button
&= ~MOD_MASK
;
2328 tx
= (x
+ TILE_SIZE
- BORDER
) / TILE_SIZE
- 1;
2329 ty
= (y
+ TILE_SIZE
- BORDER
) / TILE_SIZE
- 1;
2331 if (tx
>= 0 && tx
< cr
&& ty
>= 0 && ty
< cr
) {
2332 if (button
== LEFT_BUTTON
) {
2333 if (state
->immutable
[ty
*cr
+tx
]) {
2334 ui
->hx
= ui
->hy
= -1;
2335 } else if (tx
== ui
->hx
&& ty
== ui
->hy
&& ui
->hpencil
== 0) {
2336 ui
->hx
= ui
->hy
= -1;
2342 return ""; /* UI activity occurred */
2344 if (button
== RIGHT_BUTTON
) {
2346 * Pencil-mode highlighting for non filled squares.
2348 if (state
->grid
[ty
*cr
+tx
] == 0) {
2349 if (tx
== ui
->hx
&& ty
== ui
->hy
&& ui
->hpencil
) {
2350 ui
->hx
= ui
->hy
= -1;
2357 ui
->hx
= ui
->hy
= -1;
2359 return ""; /* UI activity occurred */
2363 if (ui
->hx
!= -1 && ui
->hy
!= -1 &&
2364 ((button
>= '1' && button
<= '9' && button
- '0' <= cr
) ||
2365 (button
>= 'a' && button
<= 'z' && button
- 'a' + 10 <= cr
) ||
2366 (button
>= 'A' && button
<= 'Z' && button
- 'A' + 10 <= cr
) ||
2368 int n
= button
- '0';
2369 if (button
>= 'A' && button
<= 'Z')
2370 n
= button
- 'A' + 10;
2371 if (button
>= 'a' && button
<= 'z')
2372 n
= button
- 'a' + 10;
2377 * Can't overwrite this square. In principle this shouldn't
2378 * happen anyway because we should never have even been
2379 * able to highlight the square, but it never hurts to be
2382 if (state
->immutable
[ui
->hy
*cr
+ui
->hx
])
2386 * Can't make pencil marks in a filled square. In principle
2387 * this shouldn't happen anyway because we should never
2388 * have even been able to pencil-highlight the square, but
2389 * it never hurts to be careful.
2391 if (ui
->hpencil
&& state
->grid
[ui
->hy
*cr
+ui
->hx
])
2394 sprintf(buf
, "%c%d,%d,%d",
2395 (char)(ui
->hpencil
&& n
> 0 ?
'P' : 'R'), ui
->hx
, ui
->hy
, n
);
2397 ui
->hx
= ui
->hy
= -1;
2405 static game_state
*execute_move(game_state
*from
, char *move
)
2407 int c
= from
->c
, r
= from
->r
, cr
= c
*r
;
2411 if (move
[0] == 'S') {
2414 ret
= dup_game(from
);
2415 ret
->completed
= ret
->cheated
= TRUE
;
2418 for (n
= 0; n
< cr
*cr
; n
++) {
2419 ret
->grid
[n
] = atoi(p
);
2421 if (!*p
|| ret
->grid
[n
] < 1 || ret
->grid
[n
] > cr
) {
2426 while (*p
&& isdigit((unsigned char)*p
)) p
++;
2431 } else if ((move
[0] == 'P' || move
[0] == 'R') &&
2432 sscanf(move
+1, "%d,%d,%d", &x
, &y
, &n
) == 3 &&
2433 x
>= 0 && x
< cr
&& y
>= 0 && y
< cr
&& n
>= 0 && n
<= cr
) {
2435 ret
= dup_game(from
);
2436 if (move
[0] == 'P' && n
> 0) {
2437 int index
= (y
*cr
+x
) * cr
+ (n
-1);
2438 ret
->pencil
[index
] = !ret
->pencil
[index
];
2440 ret
->grid
[y
*cr
+x
] = n
;
2441 memset(ret
->pencil
+ (y
*cr
+x
)*cr
, 0, cr
);
2444 * We've made a real change to the grid. Check to see
2445 * if the game has been completed.
2447 if (!ret
->completed
&& check_valid(c
, r
, ret
->grid
)) {
2448 ret
->completed
= TRUE
;
2453 return NULL
; /* couldn't parse move string */
2456 /* ----------------------------------------------------------------------
2460 #define SIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
2461 #define GETTILESIZE(cr, w) ( (double)(w-1) / (double)(cr+1) )
2463 static void game_compute_size(game_params
*params
, int tilesize
,
2466 /* Ick: fake up `ds->tilesize' for macro expansion purposes */
2467 struct { int tilesize
; } ads
, *ds
= &ads
;
2468 ads
.tilesize
= tilesize
;
2470 *x
= SIZE(params
->c
* params
->r
);
2471 *y
= SIZE(params
->c
* params
->r
);
2474 static void game_set_size(drawing
*dr
, game_drawstate
*ds
,
2475 game_params
*params
, int tilesize
)
2477 ds
->tilesize
= tilesize
;
2480 static float *game_colours(frontend
*fe
, game_state
*state
, int *ncolours
)
2482 float *ret
= snewn(3 * NCOLOURS
, float);
2484 frontend_default_colour(fe
, &ret
[COL_BACKGROUND
* 3]);
2486 ret
[COL_GRID
* 3 + 0] = 0.0F
;
2487 ret
[COL_GRID
* 3 + 1] = 0.0F
;
2488 ret
[COL_GRID
* 3 + 2] = 0.0F
;
2490 ret
[COL_CLUE
* 3 + 0] = 0.0F
;
2491 ret
[COL_CLUE
* 3 + 1] = 0.0F
;
2492 ret
[COL_CLUE
* 3 + 2] = 0.0F
;
2494 ret
[COL_USER
* 3 + 0] = 0.0F
;
2495 ret
[COL_USER
* 3 + 1] = 0.6F
* ret
[COL_BACKGROUND
* 3 + 1];
2496 ret
[COL_USER
* 3 + 2] = 0.0F
;
2498 ret
[COL_HIGHLIGHT
* 3 + 0] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 0];
2499 ret
[COL_HIGHLIGHT
* 3 + 1] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 1];
2500 ret
[COL_HIGHLIGHT
* 3 + 2] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 2];
2502 ret
[COL_ERROR
* 3 + 0] = 1.0F
;
2503 ret
[COL_ERROR
* 3 + 1] = 0.0F
;
2504 ret
[COL_ERROR
* 3 + 2] = 0.0F
;
2506 ret
[COL_PENCIL
* 3 + 0] = 0.5F
* ret
[COL_BACKGROUND
* 3 + 0];
2507 ret
[COL_PENCIL
* 3 + 1] = 0.5F
* ret
[COL_BACKGROUND
* 3 + 1];
2508 ret
[COL_PENCIL
* 3 + 2] = ret
[COL_BACKGROUND
* 3 + 2];
2510 *ncolours
= NCOLOURS
;
2514 static game_drawstate
*game_new_drawstate(drawing
*dr
, game_state
*state
)
2516 struct game_drawstate
*ds
= snew(struct game_drawstate
);
2517 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
2519 ds
->started
= FALSE
;
2523 ds
->grid
= snewn(cr
*cr
, digit
);
2524 memset(ds
->grid
, 0, cr
*cr
);
2525 ds
->pencil
= snewn(cr
*cr
*cr
, digit
);
2526 memset(ds
->pencil
, 0, cr
*cr
*cr
);
2527 ds
->hl
= snewn(cr
*cr
, unsigned char);
2528 memset(ds
->hl
, 0, cr
*cr
);
2529 ds
->entered_items
= snewn(cr
*cr
, int);
2530 ds
->tilesize
= 0; /* not decided yet */
2534 static void game_free_drawstate(drawing
*dr
, game_drawstate
*ds
)
2539 sfree(ds
->entered_items
);
2543 static void draw_number(drawing
*dr
, game_drawstate
*ds
, game_state
*state
,
2544 int x
, int y
, int hl
)
2546 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
2551 if (ds
->grid
[y
*cr
+x
] == state
->grid
[y
*cr
+x
] &&
2552 ds
->hl
[y
*cr
+x
] == hl
&&
2553 !memcmp(ds
->pencil
+(y
*cr
+x
)*cr
, state
->pencil
+(y
*cr
+x
)*cr
, cr
))
2554 return; /* no change required */
2556 tx
= BORDER
+ x
* TILE_SIZE
+ 2;
2557 ty
= BORDER
+ y
* TILE_SIZE
+ 2;
2573 clip(dr
, cx
, cy
, cw
, ch
);
2575 /* background needs erasing */
2576 draw_rect(dr
, cx
, cy
, cw
, ch
, (hl
& 15) == 1 ? COL_HIGHLIGHT
: COL_BACKGROUND
);
2578 /* pencil-mode highlight */
2579 if ((hl
& 15) == 2) {
2583 coords
[2] = cx
+cw
/2;
2586 coords
[5] = cy
+ch
/2;
2587 draw_polygon(dr
, coords
, 3, COL_HIGHLIGHT
, COL_HIGHLIGHT
);
2590 /* new number needs drawing? */
2591 if (state
->grid
[y
*cr
+x
]) {
2593 str
[0] = state
->grid
[y
*cr
+x
] + '0';
2595 str
[0] += 'a' - ('9'+1);
2596 draw_text(dr
, tx
+ TILE_SIZE
/2, ty
+ TILE_SIZE
/2,
2597 FONT_VARIABLE
, TILE_SIZE
/2, ALIGN_VCENTRE
| ALIGN_HCENTRE
,
2598 state
->immutable
[y
*cr
+x
] ? COL_CLUE
: (hl
& 16) ? COL_ERROR
: COL_USER
, str
);
2601 int pw
, ph
, pmax
, fontsize
;
2603 /* count the pencil marks required */
2604 for (i
= npencil
= 0; i
< cr
; i
++)
2605 if (state
->pencil
[(y
*cr
+x
)*cr
+i
])
2609 * It's not sensible to arrange pencil marks in the same
2610 * layout as the squares within a block, because this leads
2611 * to the font being too small. Instead, we arrange pencil
2612 * marks in the nearest thing we can to a square layout,
2613 * and we adjust the square layout depending on the number
2614 * of pencil marks in the square.
2616 for (pw
= 1; pw
* pw
< npencil
; pw
++);
2617 if (pw
< 3) pw
= 3; /* otherwise it just looks _silly_ */
2618 ph
= (npencil
+ pw
- 1) / pw
;
2619 if (ph
< 2) ph
= 2; /* likewise */
2621 fontsize
= TILE_SIZE
/(pmax
*(11-pmax
)/8);
2623 for (i
= j
= 0; i
< cr
; i
++)
2624 if (state
->pencil
[(y
*cr
+x
)*cr
+i
]) {
2625 int dx
= j
% pw
, dy
= j
/ pw
;
2630 str
[0] += 'a' - ('9'+1);
2631 draw_text(dr
, tx
+ (4*dx
+3) * TILE_SIZE
/ (4*pw
+2),
2632 ty
+ (4*dy
+3) * TILE_SIZE
/ (4*ph
+2),
2633 FONT_VARIABLE
, fontsize
,
2634 ALIGN_VCENTRE
| ALIGN_HCENTRE
, COL_PENCIL
, str
);
2641 draw_update(dr
, cx
, cy
, cw
, ch
);
2643 ds
->grid
[y
*cr
+x
] = state
->grid
[y
*cr
+x
];
2644 memcpy(ds
->pencil
+(y
*cr
+x
)*cr
, state
->pencil
+(y
*cr
+x
)*cr
, cr
);
2645 ds
->hl
[y
*cr
+x
] = hl
;
2648 static void game_redraw(drawing
*dr
, game_drawstate
*ds
, game_state
*oldstate
,
2649 game_state
*state
, int dir
, game_ui
*ui
,
2650 float animtime
, float flashtime
)
2652 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
2657 * The initial contents of the window are not guaranteed
2658 * and can vary with front ends. To be on the safe side,
2659 * all games should start by drawing a big
2660 * background-colour rectangle covering the whole window.
2662 draw_rect(dr
, 0, 0, SIZE(cr
), SIZE(cr
), COL_BACKGROUND
);
2667 for (x
= 0; x
<= cr
; x
++) {
2668 int thick
= (x
% r ?
0 : 1);
2669 draw_rect(dr
, BORDER
+ x
*TILE_SIZE
- thick
, BORDER
-1,
2670 1+2*thick
, cr
*TILE_SIZE
+3, COL_GRID
);
2672 for (y
= 0; y
<= cr
; y
++) {
2673 int thick
= (y
% c ?
0 : 1);
2674 draw_rect(dr
, BORDER
-1, BORDER
+ y
*TILE_SIZE
- thick
,
2675 cr
*TILE_SIZE
+3, 1+2*thick
, COL_GRID
);
2680 * This array is used to keep track of rows, columns and boxes
2681 * which contain a number more than once.
2683 for (x
= 0; x
< cr
* cr
; x
++)
2684 ds
->entered_items
[x
] = 0;
2685 for (x
= 0; x
< cr
; x
++)
2686 for (y
= 0; y
< cr
; y
++) {
2687 digit d
= state
->grid
[y
*cr
+x
];
2689 int box
= (x
/r
)+(y
/c
)*c
;
2690 ds
->entered_items
[x
*cr
+d
-1] |= ((ds
->entered_items
[x
*cr
+d
-1] & 1) << 1) | 1;
2691 ds
->entered_items
[y
*cr
+d
-1] |= ((ds
->entered_items
[y
*cr
+d
-1] & 4) << 1) | 4;
2692 ds
->entered_items
[box
*cr
+d
-1] |= ((ds
->entered_items
[box
*cr
+d
-1] & 16) << 1) | 16;
2697 * Draw any numbers which need redrawing.
2699 for (x
= 0; x
< cr
; x
++) {
2700 for (y
= 0; y
< cr
; y
++) {
2702 digit d
= state
->grid
[y
*cr
+x
];
2704 if (flashtime
> 0 &&
2705 (flashtime
<= FLASH_TIME
/3 ||
2706 flashtime
>= FLASH_TIME
*2/3))
2709 /* Highlight active input areas. */
2710 if (x
== ui
->hx
&& y
== ui
->hy
)
2711 highlight
= ui
->hpencil ?
2 : 1;
2713 /* Mark obvious errors (ie, numbers which occur more than once
2714 * in a single row, column, or box). */
2715 if (d
&& ((ds
->entered_items
[x
*cr
+d
-1] & 2) ||
2716 (ds
->entered_items
[y
*cr
+d
-1] & 8) ||
2717 (ds
->entered_items
[((x
/r
)+(y
/c
)*c
)*cr
+d
-1] & 32)))
2720 draw_number(dr
, ds
, state
, x
, y
, highlight
);
2725 * Update the _entire_ grid if necessary.
2728 draw_update(dr
, 0, 0, SIZE(cr
), SIZE(cr
));
2733 static float game_anim_length(game_state
*oldstate
, game_state
*newstate
,
2734 int dir
, game_ui
*ui
)
2739 static float game_flash_length(game_state
*oldstate
, game_state
*newstate
,
2740 int dir
, game_ui
*ui
)
2742 if (!oldstate
->completed
&& newstate
->completed
&&
2743 !oldstate
->cheated
&& !newstate
->cheated
)
2748 static int game_wants_statusbar(void)
2753 static int game_timing_state(game_state
*state
, game_ui
*ui
)
2758 static void game_print_size(game_params
*params
, float *x
, float *y
)
2763 * I'll use 9mm squares by default. They should be quite big
2764 * for this game, because players will want to jot down no end
2765 * of pencil marks in the squares.
2767 game_compute_size(params
, 900, &pw
, &ph
);
2772 static void game_print(drawing
*dr
, game_state
*state
, int tilesize
)
2774 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
2775 int ink
= print_mono_colour(dr
, 0);
2778 /* Ick: fake up `ds->tilesize' for macro expansion purposes */
2779 game_drawstate ads
, *ds
= &ads
;
2780 ads
.tilesize
= tilesize
;
2785 print_line_width(dr
, 3 * TILE_SIZE
/ 40);
2786 draw_rect_outline(dr
, BORDER
, BORDER
, cr
*TILE_SIZE
, cr
*TILE_SIZE
, ink
);
2791 for (x
= 1; x
< cr
; x
++) {
2792 print_line_width(dr
, (x
% r ?
1 : 3) * TILE_SIZE
/ 40);
2793 draw_line(dr
, BORDER
+x
*TILE_SIZE
, BORDER
,
2794 BORDER
+x
*TILE_SIZE
, BORDER
+cr
*TILE_SIZE
, ink
);
2796 for (y
= 1; y
< cr
; y
++) {
2797 print_line_width(dr
, (y
% c ?
1 : 3) * TILE_SIZE
/ 40);
2798 draw_line(dr
, BORDER
, BORDER
+y
*TILE_SIZE
,
2799 BORDER
+cr
*TILE_SIZE
, BORDER
+y
*TILE_SIZE
, ink
);
2805 for (y
= 0; y
< cr
; y
++)
2806 for (x
= 0; x
< cr
; x
++)
2807 if (state
->grid
[y
*cr
+x
]) {
2810 str
[0] = state
->grid
[y
*cr
+x
] + '0';
2812 str
[0] += 'a' - ('9'+1);
2813 draw_text(dr
, BORDER
+ x
*TILE_SIZE
+ TILE_SIZE
/2,
2814 BORDER
+ y
*TILE_SIZE
+ TILE_SIZE
/2,
2815 FONT_VARIABLE
, TILE_SIZE
/2,
2816 ALIGN_VCENTRE
| ALIGN_HCENTRE
, ink
, str
);
2821 #define thegame solo
2824 const struct game thegame
= {
2825 "Solo", "games.solo",
2832 TRUE
, game_configure
, custom_params
,
2840 TRUE
, game_text_format
,
2848 PREFERRED_TILE_SIZE
, game_compute_size
, game_set_size
,
2851 game_free_drawstate
,
2855 TRUE
, FALSE
, game_print_size
, game_print
,
2856 game_wants_statusbar
,
2857 FALSE
, game_timing_state
,
2858 0, /* mouse_priorities */
2861 #ifdef STANDALONE_SOLVER
2864 * gcc -DSTANDALONE_SOLVER -o solosolver solo.c malloc.c
2867 void frontend_default_colour(frontend
*fe
, float *output
) {}
2868 void draw_text(drawing
*dr
, int x
, int y
, int fonttype
, int fontsize
,
2869 int align
, int colour
, char *text
) {}
2870 void draw_rect(drawing
*dr
, int x
, int y
, int w
, int h
, int colour
) {}
2871 void draw_rect_outline(drawing
*dr
, int x
, int y
, int w
, int h
, int colour
) {}
2872 void draw_line(drawing
*dr
, int x1
, int y1
, int x2
, int y2
, int colour
) {}
2873 void draw_polygon(drawing
*dr
, int *coords
, int npoints
,
2874 int fillcolour
, int outlinecolour
) {}
2875 void clip(drawing
*dr
, int x
, int y
, int w
, int h
) {}
2876 void unclip(drawing
*dr
) {}
2877 void start_draw(drawing
*dr
) {}
2878 void draw_update(drawing
*dr
, int x
, int y
, int w
, int h
) {}
2879 void end_draw(drawing
*dr
) {}
2880 int print_mono_colour(drawing
*dr
, int grey
) { return 0; }
2881 void print_line_width(drawing
*dr
, int width
) {}
2882 unsigned long random_bits(random_state
*state
, int bits
)
2883 { assert(!"Shouldn't get randomness"); return 0; }
2884 unsigned long random_upto(random_state
*state
, unsigned long limit
)
2885 { assert(!"Shouldn't get randomness"); return 0; }
2886 void shuffle(void *array
, int nelts
, int eltsize
, random_state
*rs
)
2887 { assert(!"Shouldn't get randomness"); }
2889 void fatal(char *fmt
, ...)
2893 fprintf(stderr
, "fatal error: ");
2896 vfprintf(stderr
, fmt
, ap
);
2899 fprintf(stderr
, "\n");
2903 int main(int argc
, char **argv
)
2907 char *id
= NULL
, *desc
, *err
;
2911 while (--argc
> 0) {
2913 if (!strcmp(p
, "-v")) {
2914 solver_show_working
= TRUE
;
2915 } else if (!strcmp(p
, "-g")) {
2917 } else if (*p
== '-') {
2918 fprintf(stderr
, "%s: unrecognised option `%s'\n", argv
[0], p
);
2926 fprintf(stderr
, "usage: %s [-g | -v] <game_id>\n", argv
[0]);
2930 desc
= strchr(id
, ':');
2932 fprintf(stderr
, "%s: game id expects a colon in it\n", argv
[0]);
2937 p
= default_params();
2938 decode_params(p
, id
);
2939 err
= validate_desc(p
, desc
);
2941 fprintf(stderr
, "%s: %s\n", argv
[0], err
);
2944 s
= new_game(NULL
, p
, desc
);
2946 ret
= solver(p
->c
, p
->r
, s
->grid
, DIFF_RECURSIVE
);
2948 printf("Difficulty rating: %s\n",
2949 ret
==DIFF_BLOCK ?
"Trivial (blockwise positional elimination only)":
2950 ret
==DIFF_SIMPLE ?
"Basic (row/column/number elimination required)":
2951 ret
==DIFF_INTERSECT ?
"Intermediate (intersectional analysis required)":
2952 ret
==DIFF_SET ?
"Advanced (set elimination required)":
2953 ret
==DIFF_NEIGHBOUR ?
"Extreme (mutual neighbour elimination required)":
2954 ret
==DIFF_RECURSIVE ?
"Unreasonable (guesswork and backtracking required)":
2955 ret
==DIFF_AMBIGUOUS ?
"Ambiguous (multiple solutions exist)":
2956 ret
==DIFF_IMPOSSIBLE ?
"Impossible (no solution exists)":
2957 "INTERNAL ERROR: unrecognised difficulty code");
2959 printf("%s\n", grid_text_format(p
->c
, p
->r
, s
->grid
));