2 * solo.c: the number-placing puzzle most popularly known as `Sudoku'.
6 * - can we do anything about nasty centring of text in GTK? It
7 * seems to be taking ascenders/descenders into account when
10 * - it might still be nice to do some prioritisation on the
11 * removal of numbers from the grid
12 * + one possibility is to try to minimise the maximum number
13 * of filled squares in any block, which in particular ought
14 * to enforce never leaving a completely filled block in the
15 * puzzle as presented.
16 * + be careful of being too clever here, though, until after
17 * I've tried implementing difficulty levels. It's not
18 * impossible that those might impose much more important
19 * constraints on this process.
21 * - alternative interface modes
22 * + sudoku.com's Windows program has a palette of possible
23 * entries; you select a palette entry first and then click
24 * on the square you want it to go in, thus enabling
25 * mouse-only play. Useful for PDAs! I don't think it's
26 * actually incompatible with the current highlight-then-type
27 * approach: you _either_ highlight a palette entry and then
28 * click, _or_ you highlight a square and then type. At most
29 * one thing is ever highlighted at a time, so there's no way
31 * + `pencil marks' might be useful for more subtle forms of
32 * deduction, now we can create puzzles that require them.
36 * Solo puzzles need to be square overall (since each row and each
37 * column must contain one of every digit), but they need not be
38 * subdivided the same way internally. I am going to adopt a
39 * convention whereby I _always_ refer to `r' as the number of rows
40 * of _big_ divisions, and `c' as the number of columns of _big_
41 * divisions. Thus, a 2c by 3r puzzle looks something like this:
45 * ------+------ (Of course, you can't subdivide it the other way
46 * 1 4 5 | 6 3 2 or you'll get clashes; observe that the 4 in the
47 * 3 2 6 | 4 1 5 top left would conflict with the 4 in the second
48 * ------+------ box down on the left-hand side.)
52 * The need for a strong naming convention should now be clear:
53 * each small box is two rows of digits by three columns, while the
54 * overall puzzle has three rows of small boxes by two columns. So
55 * I will (hopefully) consistently use `r' to denote the number of
56 * rows _of small boxes_ (here 3), which is also the number of
57 * columns of digits in each small box; and `c' vice versa (here
60 * I'm also going to choose arbitrarily to list c first wherever
61 * possible: the above is a 2x3 puzzle, not a 3x2 one.
71 #ifdef STANDALONE_SOLVER
73 int solver_show_working
;
78 #define max(x,y) ((x)>(y)?(x):(y))
81 * To save space, I store digits internally as unsigned char. This
82 * imposes a hard limit of 255 on the order of the puzzle. Since
83 * even a 5x5 takes unacceptably long to generate, I don't see this
84 * as a serious limitation unless something _really_ impressive
85 * happens in computing technology; but here's a typedef anyway for
86 * general good practice.
88 typedef unsigned char digit
;
94 #define FLASH_TIME 0.4F
96 enum { SYMM_NONE
, SYMM_ROT2
, SYMM_ROT4
, SYMM_REF4
};
98 enum { DIFF_BLOCK
, DIFF_SIMPLE
, DIFF_INTERSECT
,
99 DIFF_SET
, DIFF_RECURSIVE
, DIFF_AMBIGUOUS
, DIFF_IMPOSSIBLE
};
111 int c
, r
, symm
, diff
;
117 unsigned char *immutable
; /* marks which digits are clues */
121 static game_params
*default_params(void)
123 game_params
*ret
= snew(game_params
);
126 ret
->symm
= SYMM_ROT2
; /* a plausible default */
127 ret
->diff
= DIFF_SIMPLE
; /* so is this */
132 static void free_params(game_params
*params
)
137 static game_params
*dup_params(game_params
*params
)
139 game_params
*ret
= snew(game_params
);
140 *ret
= *params
; /* structure copy */
144 static int game_fetch_preset(int i
, char **name
, game_params
**params
)
150 { "2x2 Trivial", { 2, 2, SYMM_ROT2
, DIFF_BLOCK
} },
151 { "2x3 Basic", { 2, 3, SYMM_ROT2
, DIFF_SIMPLE
} },
152 { "3x3 Basic", { 3, 3, SYMM_ROT2
, DIFF_SIMPLE
} },
153 { "3x3 Intermediate", { 3, 3, SYMM_ROT2
, DIFF_INTERSECT
} },
154 { "3x3 Advanced", { 3, 3, SYMM_ROT2
, DIFF_SET
} },
155 { "3x4 Basic", { 3, 4, SYMM_ROT2
, DIFF_SIMPLE
} },
156 { "4x4 Basic", { 4, 4, SYMM_ROT2
, DIFF_SIMPLE
} },
159 if (i
< 0 || i
>= lenof(presets
))
162 *name
= dupstr(presets
[i
].title
);
163 *params
= dup_params(&presets
[i
].params
);
168 static game_params
*decode_params(char const *string
)
170 game_params
*ret
= default_params();
172 ret
->c
= ret
->r
= atoi(string
);
173 ret
->symm
= SYMM_ROT2
;
174 while (*string
&& isdigit((unsigned char)*string
)) string
++;
175 if (*string
== 'x') {
177 ret
->r
= atoi(string
);
178 while (*string
&& isdigit((unsigned char)*string
)) string
++;
181 if (*string
== 'r' || *string
== 'm' || *string
== 'a') {
185 while (*string
&& isdigit((unsigned char)*string
)) string
++;
186 if (sc
== 'm' && sn
== 4)
187 ret
->symm
= SYMM_REF4
;
188 if (sc
== 'r' && sn
== 4)
189 ret
->symm
= SYMM_ROT4
;
190 if (sc
== 'r' && sn
== 2)
191 ret
->symm
= SYMM_ROT2
;
193 ret
->symm
= SYMM_NONE
;
194 } else if (*string
== 'd') {
196 if (*string
== 't') /* trivial */
197 string
++, ret
->diff
= DIFF_BLOCK
;
198 else if (*string
== 'b') /* basic */
199 string
++, ret
->diff
= DIFF_SIMPLE
;
200 else if (*string
== 'i') /* intermediate */
201 string
++, ret
->diff
= DIFF_INTERSECT
;
202 else if (*string
== 'a') /* advanced */
203 string
++, ret
->diff
= DIFF_SET
;
205 string
++; /* eat unknown character */
211 static char *encode_params(game_params
*params
)
216 * Symmetry is a game generation preference and hence is left
217 * out of the encoding. Users can add it back in as they see
220 sprintf(str
, "%dx%d", params
->c
, params
->r
);
224 static config_item
*game_configure(game_params
*params
)
229 ret
= snewn(5, config_item
);
231 ret
[0].name
= "Columns of sub-blocks";
232 ret
[0].type
= C_STRING
;
233 sprintf(buf
, "%d", params
->c
);
234 ret
[0].sval
= dupstr(buf
);
237 ret
[1].name
= "Rows of sub-blocks";
238 ret
[1].type
= C_STRING
;
239 sprintf(buf
, "%d", params
->r
);
240 ret
[1].sval
= dupstr(buf
);
243 ret
[2].name
= "Symmetry";
244 ret
[2].type
= C_CHOICES
;
245 ret
[2].sval
= ":None:2-way rotation:4-way rotation:4-way mirror";
246 ret
[2].ival
= params
->symm
;
248 ret
[3].name
= "Difficulty";
249 ret
[3].type
= C_CHOICES
;
250 ret
[3].sval
= ":Trivial:Basic:Intermediate:Advanced";
251 ret
[3].ival
= params
->diff
;
261 static game_params
*custom_params(config_item
*cfg
)
263 game_params
*ret
= snew(game_params
);
265 ret
->c
= atoi(cfg
[0].sval
);
266 ret
->r
= atoi(cfg
[1].sval
);
267 ret
->symm
= cfg
[2].ival
;
268 ret
->diff
= cfg
[3].ival
;
273 static char *validate_params(game_params
*params
)
275 if (params
->c
< 2 || params
->r
< 2)
276 return "Both dimensions must be at least 2";
277 if (params
->c
> ORDER_MAX
|| params
->r
> ORDER_MAX
)
278 return "Dimensions greater than "STR(ORDER_MAX
)" are not supported";
282 /* ----------------------------------------------------------------------
283 * Full recursive Solo solver.
285 * The algorithm for this solver is shamelessly copied from a
286 * Python solver written by Andrew Wilkinson (which is GPLed, but
287 * I've reused only ideas and no code). It mostly just does the
288 * obvious recursive thing: pick an empty square, put one of the
289 * possible digits in it, recurse until all squares are filled,
290 * backtrack and change some choices if necessary.
292 * The clever bit is that every time it chooses which square to
293 * fill in next, it does so by counting the number of _possible_
294 * numbers that can go in each square, and it prioritises so that
295 * it picks a square with the _lowest_ number of possibilities. The
296 * idea is that filling in lots of the obvious bits (particularly
297 * any squares with only one possibility) will cut down on the list
298 * of possibilities for other squares and hence reduce the enormous
299 * search space as much as possible as early as possible.
301 * In practice the algorithm appeared to work very well; run on
302 * sample problems from the Times it completed in well under a
303 * second on my G5 even when written in Python, and given an empty
304 * grid (so that in principle it would enumerate _all_ solved
305 * grids!) it found the first valid solution just as quickly. So
306 * with a bit more randomisation I see no reason not to use this as
311 * Internal data structure used in solver to keep track of
314 struct rsolve_coord
{ int x
, y
, r
; };
315 struct rsolve_usage
{
316 int c
, r
, cr
; /* cr == c*r */
317 /* grid is a copy of the input grid, modified as we go along */
319 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
321 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
323 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
325 /* This lists all the empty spaces remaining in the grid. */
326 struct rsolve_coord
*spaces
;
328 /* If we need randomisation in the solve, this is our random state. */
330 /* Number of solutions so far found, and maximum number we care about. */
335 * The real recursive step in the solving function.
337 static void rsolve_real(struct rsolve_usage
*usage
, digit
*grid
)
339 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
340 int i
, j
, n
, sx
, sy
, bestm
, bestr
;
344 * Firstly, check for completion! If there are no spaces left
345 * in the grid, we have a solution.
347 if (usage
->nspaces
== 0) {
350 * This is our first solution, so fill in the output grid.
352 memcpy(grid
, usage
->grid
, cr
* cr
);
359 * Otherwise, there must be at least one space. Find the most
360 * constrained space, using the `r' field as a tie-breaker.
362 bestm
= cr
+1; /* so that any space will beat it */
365 for (j
= 0; j
< usage
->nspaces
; j
++) {
366 int x
= usage
->spaces
[j
].x
, y
= usage
->spaces
[j
].y
;
370 * Find the number of digits that could go in this space.
373 for (n
= 0; n
< cr
; n
++)
374 if (!usage
->row
[y
*cr
+n
] && !usage
->col
[x
*cr
+n
] &&
375 !usage
->blk
[((y
/c
)*c
+(x
/r
))*cr
+n
])
378 if (m
< bestm
|| (m
== bestm
&& usage
->spaces
[j
].r
< bestr
)) {
380 bestr
= usage
->spaces
[j
].r
;
388 * Swap that square into the final place in the spaces array,
389 * so that decrementing nspaces will remove it from the list.
391 if (i
!= usage
->nspaces
-1) {
392 struct rsolve_coord t
;
393 t
= usage
->spaces
[usage
->nspaces
-1];
394 usage
->spaces
[usage
->nspaces
-1] = usage
->spaces
[i
];
395 usage
->spaces
[i
] = t
;
399 * Now we've decided which square to start our recursion at,
400 * simply go through all possible values, shuffling them
401 * randomly first if necessary.
403 digits
= snewn(bestm
, int);
405 for (n
= 0; n
< cr
; n
++)
406 if (!usage
->row
[sy
*cr
+n
] && !usage
->col
[sx
*cr
+n
] &&
407 !usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
]) {
413 for (i
= j
; i
> 1; i
--) {
414 int p
= random_upto(usage
->rs
, i
);
417 digits
[p
] = digits
[i
-1];
423 /* And finally, go through the digit list and actually recurse. */
424 for (i
= 0; i
< j
; i
++) {
427 /* Update the usage structure to reflect the placing of this digit. */
428 usage
->row
[sy
*cr
+n
-1] = usage
->col
[sx
*cr
+n
-1] =
429 usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
-1] = TRUE
;
430 usage
->grid
[sy
*cr
+sx
] = n
;
433 /* Call the solver recursively. */
434 rsolve_real(usage
, grid
);
437 * If we have seen as many solutions as we need, terminate
438 * all processing immediately.
440 if (usage
->solns
>= usage
->maxsolns
)
443 /* Revert the usage structure. */
444 usage
->row
[sy
*cr
+n
-1] = usage
->col
[sx
*cr
+n
-1] =
445 usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
-1] = FALSE
;
446 usage
->grid
[sy
*cr
+sx
] = 0;
454 * Entry point to solver. You give it dimensions and a starting
455 * grid, which is simply an array of N^4 digits. In that array, 0
456 * means an empty square, and 1..N mean a clue square.
458 * Return value is the number of solutions found; searching will
459 * stop after the provided `max'. (Thus, you can pass max==1 to
460 * indicate that you only care about finding _one_ solution, or
461 * max==2 to indicate that you want to know the difference between
462 * a unique and non-unique solution.) The input parameter `grid' is
463 * also filled in with the _first_ (or only) solution found by the
466 static int rsolve(int c
, int r
, digit
*grid
, random_state
*rs
, int max
)
468 struct rsolve_usage
*usage
;
473 * Create an rsolve_usage structure.
475 usage
= snew(struct rsolve_usage
);
481 usage
->grid
= snewn(cr
* cr
, digit
);
482 memcpy(usage
->grid
, grid
, cr
* cr
);
484 usage
->row
= snewn(cr
* cr
, unsigned char);
485 usage
->col
= snewn(cr
* cr
, unsigned char);
486 usage
->blk
= snewn(cr
* cr
, unsigned char);
487 memset(usage
->row
, FALSE
, cr
* cr
);
488 memset(usage
->col
, FALSE
, cr
* cr
);
489 memset(usage
->blk
, FALSE
, cr
* cr
);
491 usage
->spaces
= snewn(cr
* cr
, struct rsolve_coord
);
495 usage
->maxsolns
= max
;
500 * Now fill it in with data from the input grid.
502 for (y
= 0; y
< cr
; y
++) {
503 for (x
= 0; x
< cr
; x
++) {
504 int v
= grid
[y
*cr
+x
];
506 usage
->spaces
[usage
->nspaces
].x
= x
;
507 usage
->spaces
[usage
->nspaces
].y
= y
;
509 usage
->spaces
[usage
->nspaces
].r
= random_bits(rs
, 31);
511 usage
->spaces
[usage
->nspaces
].r
= usage
->nspaces
;
514 usage
->row
[y
*cr
+v
-1] = TRUE
;
515 usage
->col
[x
*cr
+v
-1] = TRUE
;
516 usage
->blk
[((y
/c
)*c
+(x
/r
))*cr
+v
-1] = TRUE
;
522 * Run the real recursive solving function.
524 rsolve_real(usage
, grid
);
528 * Clean up the usage structure now we have our answer.
530 sfree(usage
->spaces
);
543 /* ----------------------------------------------------------------------
544 * End of recursive solver code.
547 /* ----------------------------------------------------------------------
548 * Less capable non-recursive solver. This one is used to check
549 * solubility of a grid as we gradually remove numbers from it: by
550 * verifying a grid using this solver we can ensure it isn't _too_
551 * hard (e.g. does not actually require guessing and backtracking).
553 * It supports a variety of specific modes of reasoning. By
554 * enabling or disabling subsets of these modes we can arrange a
555 * range of difficulty levels.
559 * Modes of reasoning currently supported:
561 * - Positional elimination: a number must go in a particular
562 * square because all the other empty squares in a given
563 * row/col/blk are ruled out.
565 * - Numeric elimination: a square must have a particular number
566 * in because all the other numbers that could go in it are
569 * - Intersectional analysis: given two domains which overlap
570 * (hence one must be a block, and the other can be a row or
571 * col), if the possible locations for a particular number in
572 * one of the domains can be narrowed down to the overlap, then
573 * that number can be ruled out everywhere but the overlap in
574 * the other domain too.
576 * - Set elimination: if there is a subset of the empty squares
577 * within a domain such that the union of the possible numbers
578 * in that subset has the same size as the subset itself, then
579 * those numbers can be ruled out everywhere else in the domain.
580 * (For example, if there are five empty squares and the
581 * possible numbers in each are 12, 23, 13, 134 and 1345, then
582 * the first three empty squares form such a subset: the numbers
583 * 1, 2 and 3 _must_ be in those three squares in some
584 * permutation, and hence we can deduce none of them can be in
585 * the fourth or fifth squares.)
586 * + You can also see this the other way round, concentrating
587 * on numbers rather than squares: if there is a subset of
588 * the unplaced numbers within a domain such that the union
589 * of all their possible positions has the same size as the
590 * subset itself, then all other numbers can be ruled out for
591 * those positions. However, it turns out that this is
592 * exactly equivalent to the first formulation at all times:
593 * there is a 1-1 correspondence between suitable subsets of
594 * the unplaced numbers and suitable subsets of the unfilled
595 * places, found by taking the _complement_ of the union of
596 * the numbers' possible positions (or the spaces' possible
601 * Within this solver, I'm going to transform all y-coordinates by
602 * inverting the significance of the block number and the position
603 * within the block. That is, we will start with the top row of
604 * each block in order, then the second row of each block in order,
607 * This transformation has the enormous advantage that it means
608 * every row, column _and_ block is described by an arithmetic
609 * progression of coordinates within the cubic array, so that I can
610 * use the same very simple function to do blockwise, row-wise and
611 * column-wise elimination.
613 #define YTRANS(y) (((y)%c)*r+(y)/c)
614 #define YUNTRANS(y) (((y)%r)*c+(y)/r)
616 struct nsolve_usage
{
619 * We set up a cubic array, indexed by x, y and digit; each
620 * element of this array is TRUE or FALSE according to whether
621 * or not that digit _could_ in principle go in that position.
623 * The way to index this array is cube[(x*cr+y)*cr+n-1].
624 * y-coordinates in here are transformed.
628 * This is the grid in which we write down our final
629 * deductions. y-coordinates in here are _not_ transformed.
633 * Now we keep track, at a slightly higher level, of what we
634 * have yet to work out, to prevent doing the same deduction
637 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
639 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
641 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
644 #define cubepos(x,y,n) (((x)*usage->cr+(y))*usage->cr+(n)-1)
645 #define cube(x,y,n) (usage->cube[cubepos(x,y,n)])
648 * Function called when we are certain that a particular square has
649 * a particular number in it. The y-coordinate passed in here is
652 static void nsolve_place(struct nsolve_usage
*usage
, int x
, int y
, int n
)
654 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
660 * Rule out all other numbers in this square.
662 for (i
= 1; i
<= cr
; i
++)
667 * Rule out this number in all other positions in the row.
669 for (i
= 0; i
< cr
; i
++)
674 * Rule out this number in all other positions in the column.
676 for (i
= 0; i
< cr
; i
++)
681 * Rule out this number in all other positions in the block.
685 for (i
= 0; i
< r
; i
++)
686 for (j
= 0; j
< c
; j
++)
687 if (bx
+i
!= x
|| by
+j
*r
!= y
)
688 cube(bx
+i
,by
+j
*r
,n
) = FALSE
;
691 * Enter the number in the result grid.
693 usage
->grid
[YUNTRANS(y
)*cr
+x
] = n
;
696 * Cross out this number from the list of numbers left to place
697 * in its row, its column and its block.
699 usage
->row
[y
*cr
+n
-1] = usage
->col
[x
*cr
+n
-1] =
700 usage
->blk
[((y
%r
)*c
+(x
/r
))*cr
+n
-1] = TRUE
;
703 static int nsolve_elim(struct nsolve_usage
*usage
, int start
, int step
704 #ifdef STANDALONE_SOLVER
709 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
713 * Count the number of set bits within this section of the
718 for (i
= 0; i
< cr
; i
++)
719 if (usage
->cube
[start
+i
*step
]) {
733 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
]) {
734 #ifdef STANDALONE_SOLVER
735 if (solver_show_working
) {
740 printf(":\n placing %d at (%d,%d)\n",
741 n
, 1+x
, 1+YUNTRANS(y
));
744 nsolve_place(usage
, x
, y
, n
);
752 static int nsolve_intersect(struct nsolve_usage
*usage
,
753 int start1
, int step1
, int start2
, int step2
754 #ifdef STANDALONE_SOLVER
759 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
763 * Loop over the first domain and see if there's any set bit
764 * not also in the second.
766 for (i
= 0; i
< cr
; i
++) {
767 int p
= start1
+i
*step1
;
768 if (usage
->cube
[p
] &&
769 !(p
>= start2
&& p
< start2
+cr
*step2
&&
770 (p
- start2
) % step2
== 0))
771 return FALSE
; /* there is, so we can't deduce */
775 * We have determined that all set bits in the first domain are
776 * within its overlap with the second. So loop over the second
777 * domain and remove all set bits that aren't also in that
778 * overlap; return TRUE iff we actually _did_ anything.
781 for (i
= 0; i
< cr
; i
++) {
782 int p
= start2
+i
*step2
;
783 if (usage
->cube
[p
] &&
784 !(p
>= start1
&& p
< start1
+cr
*step1
&& (p
- start1
) % step1
== 0))
786 #ifdef STANDALONE_SOLVER
787 if (solver_show_working
) {
803 printf(" ruling out %d at (%d,%d)\n",
804 pn
, 1+px
, 1+YUNTRANS(py
));
807 ret
= TRUE
; /* we did something */
815 static int nsolve_set(struct nsolve_usage
*usage
,
816 int start
, int step1
, int step2
817 #ifdef STANDALONE_SOLVER
822 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
824 unsigned char *grid
= snewn(cr
*cr
, unsigned char);
825 unsigned char *rowidx
= snewn(cr
, unsigned char);
826 unsigned char *colidx
= snewn(cr
, unsigned char);
827 unsigned char *set
= snewn(cr
, unsigned char);
830 * We are passed a cr-by-cr matrix of booleans. Our first job
831 * is to winnow it by finding any definite placements - i.e.
832 * any row with a solitary 1 - and discarding that row and the
833 * column containing the 1.
835 memset(rowidx
, TRUE
, cr
);
836 memset(colidx
, TRUE
, cr
);
837 for (i
= 0; i
< cr
; i
++) {
838 int count
= 0, first
= -1;
839 for (j
= 0; j
< cr
; j
++)
840 if (usage
->cube
[start
+i
*step1
+j
*step2
])
844 * This condition actually marks a completely insoluble
845 * (i.e. internally inconsistent) puzzle. We return and
846 * report no progress made.
851 rowidx
[i
] = colidx
[first
] = FALSE
;
855 * Convert each of rowidx/colidx from a list of 0s and 1s to a
856 * list of the indices of the 1s.
858 for (i
= j
= 0; i
< cr
; i
++)
862 for (i
= j
= 0; i
< cr
; i
++)
868 * And create the smaller matrix.
870 for (i
= 0; i
< n
; i
++)
871 for (j
= 0; j
< n
; j
++)
872 grid
[i
*cr
+j
] = usage
->cube
[start
+rowidx
[i
]*step1
+colidx
[j
]*step2
];
875 * Having done that, we now have a matrix in which every row
876 * has at least two 1s in. Now we search to see if we can find
877 * a rectangle of zeroes (in the set-theoretic sense of
878 * `rectangle', i.e. a subset of rows crossed with a subset of
879 * columns) whose width and height add up to n.
886 * We have a candidate set. If its size is <=1 or >=n-1
887 * then we move on immediately.
889 if (count
> 1 && count
< n
-1) {
891 * The number of rows we need is n-count. See if we can
892 * find that many rows which each have a zero in all
893 * the positions listed in `set'.
896 for (i
= 0; i
< n
; i
++) {
898 for (j
= 0; j
< n
; j
++)
899 if (set
[j
] && grid
[i
*cr
+j
]) {
908 * We expect never to be able to get _more_ than
909 * n-count suitable rows: this would imply that (for
910 * example) there are four numbers which between them
911 * have at most three possible positions, and hence it
912 * indicates a faulty deduction before this point or
915 assert(rows
<= n
- count
);
916 if (rows
>= n
- count
) {
917 int progress
= FALSE
;
920 * We've got one! Now, for each row which _doesn't_
921 * satisfy the criterion, eliminate all its set
922 * bits in the positions _not_ listed in `set'.
923 * Return TRUE (meaning progress has been made) if
924 * we successfully eliminated anything at all.
926 * This involves referring back through
927 * rowidx/colidx in order to work out which actual
928 * positions in the cube to meddle with.
930 for (i
= 0; i
< n
; i
++) {
932 for (j
= 0; j
< n
; j
++)
933 if (set
[j
] && grid
[i
*cr
+j
]) {
938 for (j
= 0; j
< n
; j
++)
939 if (!set
[j
] && grid
[i
*cr
+j
]) {
940 int fpos
= (start
+rowidx
[i
]*step1
+
942 #ifdef STANDALONE_SOLVER
943 if (solver_show_working
) {
959 printf(" ruling out %d at (%d,%d)\n",
960 pn
, 1+px
, 1+YUNTRANS(py
));
964 usage
->cube
[fpos
] = FALSE
;
980 * Binary increment: change the rightmost 0 to a 1, and
981 * change all 1s to the right of it to 0s.
984 while (i
> 0 && set
[i
-1])
985 set
[--i
] = 0, count
--;
987 set
[--i
] = 1, count
++;
1000 static int nsolve(int c
, int r
, digit
*grid
)
1002 struct nsolve_usage
*usage
;
1005 int diff
= DIFF_BLOCK
;
1008 * Set up a usage structure as a clean slate (everything
1011 usage
= snew(struct nsolve_usage
);
1015 usage
->cube
= snewn(cr
*cr
*cr
, unsigned char);
1016 usage
->grid
= grid
; /* write straight back to the input */
1017 memset(usage
->cube
, TRUE
, cr
*cr
*cr
);
1019 usage
->row
= snewn(cr
* cr
, unsigned char);
1020 usage
->col
= snewn(cr
* cr
, unsigned char);
1021 usage
->blk
= snewn(cr
* cr
, unsigned char);
1022 memset(usage
->row
, FALSE
, cr
* cr
);
1023 memset(usage
->col
, FALSE
, cr
* cr
);
1024 memset(usage
->blk
, FALSE
, cr
* cr
);
1027 * Place all the clue numbers we are given.
1029 for (x
= 0; x
< cr
; x
++)
1030 for (y
= 0; y
< cr
; y
++)
1032 nsolve_place(usage
, x
, YTRANS(y
), grid
[y
*cr
+x
]);
1035 * Now loop over the grid repeatedly trying all permitted modes
1036 * of reasoning. The loop terminates if we complete an
1037 * iteration without making any progress; we then return
1038 * failure or success depending on whether the grid is full or
1043 * I'd like to write `continue;' inside each of the
1044 * following loops, so that the solver returns here after
1045 * making some progress. However, I can't specify that I
1046 * want to continue an outer loop rather than the innermost
1047 * one, so I'm apologetically resorting to a goto.
1052 * Blockwise positional elimination.
1054 for (x
= 0; x
< cr
; x
+= r
)
1055 for (y
= 0; y
< r
; y
++)
1056 for (n
= 1; n
<= cr
; n
++)
1057 if (!usage
->blk
[(y
*c
+(x
/r
))*cr
+n
-1] &&
1058 nsolve_elim(usage
, cubepos(x
,y
,n
), r
*cr
1059 #ifdef STANDALONE_SOLVER
1060 , "positional elimination,"
1061 " block (%d,%d)", 1+x
/r
, 1+y
1064 diff
= max(diff
, DIFF_BLOCK
);
1069 * Row-wise positional elimination.
1071 for (y
= 0; y
< cr
; y
++)
1072 for (n
= 1; n
<= cr
; n
++)
1073 if (!usage
->row
[y
*cr
+n
-1] &&
1074 nsolve_elim(usage
, cubepos(0,y
,n
), cr
*cr
1075 #ifdef STANDALONE_SOLVER
1076 , "positional elimination,"
1077 " row %d", 1+YUNTRANS(y
)
1080 diff
= max(diff
, DIFF_SIMPLE
);
1084 * Column-wise positional elimination.
1086 for (x
= 0; x
< cr
; x
++)
1087 for (n
= 1; n
<= cr
; n
++)
1088 if (!usage
->col
[x
*cr
+n
-1] &&
1089 nsolve_elim(usage
, cubepos(x
,0,n
), cr
1090 #ifdef STANDALONE_SOLVER
1091 , "positional elimination," " column %d", 1+x
1094 diff
= max(diff
, DIFF_SIMPLE
);
1099 * Numeric elimination.
1101 for (x
= 0; x
< cr
; x
++)
1102 for (y
= 0; y
< cr
; y
++)
1103 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
] &&
1104 nsolve_elim(usage
, cubepos(x
,y
,1), 1
1105 #ifdef STANDALONE_SOLVER
1106 , "numeric elimination at (%d,%d)", 1+x
,
1110 diff
= max(diff
, DIFF_SIMPLE
);
1115 * Intersectional analysis, rows vs blocks.
1117 for (y
= 0; y
< cr
; y
++)
1118 for (x
= 0; x
< cr
; x
+= r
)
1119 for (n
= 1; n
<= cr
; n
++)
1120 if (!usage
->row
[y
*cr
+n
-1] &&
1121 !usage
->blk
[((y
%r
)*c
+(x
/r
))*cr
+n
-1] &&
1122 (nsolve_intersect(usage
, cubepos(0,y
,n
), cr
*cr
,
1123 cubepos(x
,y
%r
,n
), r
*cr
1124 #ifdef STANDALONE_SOLVER
1125 , "intersectional analysis,"
1126 " row %d vs block (%d,%d)",
1127 1+YUNTRANS(y
), 1+x
, 1+y
%r
1130 nsolve_intersect(usage
, cubepos(x
,y
%r
,n
), r
*cr
,
1131 cubepos(0,y
,n
), cr
*cr
1132 #ifdef STANDALONE_SOLVER
1133 , "intersectional analysis,"
1134 " block (%d,%d) vs row %d",
1135 1+x
, 1+y
%r
, 1+YUNTRANS(y
)
1138 diff
= max(diff
, DIFF_INTERSECT
);
1143 * Intersectional analysis, columns vs blocks.
1145 for (x
= 0; x
< cr
; x
++)
1146 for (y
= 0; y
< r
; y
++)
1147 for (n
= 1; n
<= cr
; n
++)
1148 if (!usage
->col
[x
*cr
+n
-1] &&
1149 !usage
->blk
[(y
*c
+(x
/r
))*cr
+n
-1] &&
1150 (nsolve_intersect(usage
, cubepos(x
,0,n
), cr
,
1151 cubepos((x
/r
)*r
,y
,n
), r
*cr
1152 #ifdef STANDALONE_SOLVER
1153 , "intersectional analysis,"
1154 " column %d vs block (%d,%d)",
1158 nsolve_intersect(usage
, cubepos((x
/r
)*r
,y
,n
), r
*cr
,
1160 #ifdef STANDALONE_SOLVER
1161 , "intersectional analysis,"
1162 " block (%d,%d) vs column %d",
1166 diff
= max(diff
, DIFF_INTERSECT
);
1171 * Blockwise set elimination.
1173 for (x
= 0; x
< cr
; x
+= r
)
1174 for (y
= 0; y
< r
; y
++)
1175 if (nsolve_set(usage
, cubepos(x
,y
,1), r
*cr
, 1
1176 #ifdef STANDALONE_SOLVER
1177 , "set elimination, block (%d,%d)", 1+x
/r
, 1+y
1180 diff
= max(diff
, DIFF_SET
);
1185 * Row-wise set elimination.
1187 for (y
= 0; y
< cr
; y
++)
1188 if (nsolve_set(usage
, cubepos(0,y
,1), cr
*cr
, 1
1189 #ifdef STANDALONE_SOLVER
1190 , "set elimination, row %d", 1+YUNTRANS(y
)
1193 diff
= max(diff
, DIFF_SET
);
1198 * Column-wise set elimination.
1200 for (x
= 0; x
< cr
; x
++)
1201 if (nsolve_set(usage
, cubepos(x
,0,1), cr
, 1
1202 #ifdef STANDALONE_SOLVER
1203 , "set elimination, column %d", 1+x
1206 diff
= max(diff
, DIFF_SET
);
1211 * If we reach here, we have made no deductions in this
1212 * iteration, so the algorithm terminates.
1223 for (x
= 0; x
< cr
; x
++)
1224 for (y
= 0; y
< cr
; y
++)
1226 return DIFF_IMPOSSIBLE
;
1230 /* ----------------------------------------------------------------------
1231 * End of non-recursive solver code.
1235 * Check whether a grid contains a valid complete puzzle.
1237 static int check_valid(int c
, int r
, digit
*grid
)
1240 unsigned char *used
;
1243 used
= snewn(cr
, unsigned char);
1246 * Check that each row contains precisely one of everything.
1248 for (y
= 0; y
< cr
; y
++) {
1249 memset(used
, FALSE
, cr
);
1250 for (x
= 0; x
< cr
; x
++)
1251 if (grid
[y
*cr
+x
] > 0 && grid
[y
*cr
+x
] <= cr
)
1252 used
[grid
[y
*cr
+x
]-1] = TRUE
;
1253 for (n
= 0; n
< cr
; n
++)
1261 * Check that each column contains precisely one of everything.
1263 for (x
= 0; x
< cr
; x
++) {
1264 memset(used
, FALSE
, cr
);
1265 for (y
= 0; y
< cr
; y
++)
1266 if (grid
[y
*cr
+x
] > 0 && grid
[y
*cr
+x
] <= cr
)
1267 used
[grid
[y
*cr
+x
]-1] = TRUE
;
1268 for (n
= 0; n
< cr
; n
++)
1276 * Check that each block contains precisely one of everything.
1278 for (x
= 0; x
< cr
; x
+= r
) {
1279 for (y
= 0; y
< cr
; y
+= c
) {
1281 memset(used
, FALSE
, cr
);
1282 for (xx
= x
; xx
< x
+r
; xx
++)
1283 for (yy
= 0; yy
< y
+c
; yy
++)
1284 if (grid
[yy
*cr
+xx
] > 0 && grid
[yy
*cr
+xx
] <= cr
)
1285 used
[grid
[yy
*cr
+xx
]-1] = TRUE
;
1286 for (n
= 0; n
< cr
; n
++)
1298 static void symmetry_limit(game_params
*params
, int *xlim
, int *ylim
, int s
)
1300 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1312 *xlim
= *ylim
= (cr
+1) / 2;
1317 static int symmetries(game_params
*params
, int x
, int y
, int *output
, int s
)
1319 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1328 break; /* just x,y is all we need */
1333 *output
++ = cr
- 1 - x
;
1338 *output
++ = cr
- 1 - y
;
1342 *output
++ = cr
- 1 - y
;
1347 *output
++ = cr
- 1 - x
;
1353 *output
++ = cr
- 1 - x
;
1354 *output
++ = cr
- 1 - y
;
1362 static char *new_game_seed(game_params
*params
, random_state
*rs
)
1364 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1366 digit
*grid
, *grid2
;
1367 struct xy
{ int x
, y
; } *locs
;
1371 int coords
[16], ncoords
;
1376 * Adjust the maximum difficulty level to be consistent with
1377 * the puzzle size: all 2x2 puzzles appear to be Trivial
1378 * (DIFF_BLOCK) so we cannot hold out for even a Basic
1379 * (DIFF_SIMPLE) one.
1381 maxdiff
= params
->diff
;
1382 if (c
== 2 && r
== 2)
1383 maxdiff
= DIFF_BLOCK
;
1385 grid
= snewn(area
, digit
);
1386 locs
= snewn(area
, struct xy
);
1387 grid2
= snewn(area
, digit
);
1390 * Loop until we get a grid of the required difficulty. This is
1391 * nasty, but it seems to be unpleasantly hard to generate
1392 * difficult grids otherwise.
1396 * Start the recursive solver with an empty grid to generate a
1397 * random solved state.
1399 memset(grid
, 0, area
);
1400 ret
= rsolve(c
, r
, grid
, rs
, 1);
1402 assert(check_valid(c
, r
, grid
));
1405 * Now we have a solved grid, start removing things from it
1406 * while preserving solubility.
1408 symmetry_limit(params
, &xlim
, &ylim
, params
->symm
);
1413 * Iterate over the grid and enumerate all the filled
1414 * squares we could empty.
1418 for (x
= 0; x
< xlim
; x
++)
1419 for (y
= 0; y
< ylim
; y
++)
1427 * Now shuffle that list.
1429 for (i
= nlocs
; i
> 1; i
--) {
1430 int p
= random_upto(rs
, i
);
1432 struct xy t
= locs
[p
];
1433 locs
[p
] = locs
[i
-1];
1439 * Now loop over the shuffled list and, for each element,
1440 * see whether removing that element (and its reflections)
1441 * from the grid will still leave the grid soluble by
1444 for (i
= 0; i
< nlocs
; i
++) {
1448 memcpy(grid2
, grid
, area
);
1449 ncoords
= symmetries(params
, x
, y
, coords
, params
->symm
);
1450 for (j
= 0; j
< ncoords
; j
++)
1451 grid2
[coords
[2*j
+1]*cr
+coords
[2*j
]] = 0;
1453 if (nsolve(c
, r
, grid2
) <= maxdiff
) {
1454 for (j
= 0; j
< ncoords
; j
++)
1455 grid
[coords
[2*j
+1]*cr
+coords
[2*j
]] = 0;
1462 * There was nothing we could remove without destroying
1469 memcpy(grid2
, grid
, area
);
1470 } while (nsolve(c
, r
, grid2
) != maxdiff
);
1476 * Now we have the grid as it will be presented to the user.
1477 * Encode it in a game seed.
1483 seed
= snewn(5 * area
, char);
1486 for (i
= 0; i
<= area
; i
++) {
1487 int n
= (i
< area ? grid
[i
] : -1);
1494 int c
= 'a' - 1 + run
;
1498 run
-= c
- ('a' - 1);
1502 * If there's a number in the very top left or
1503 * bottom right, there's no point putting an
1504 * unnecessary _ before or after it.
1506 if (p
> seed
&& n
> 0)
1510 p
+= sprintf(p
, "%d", n
);
1514 assert(p
- seed
< 5 * area
);
1516 seed
= sresize(seed
, p
- seed
, char);
1524 static char *validate_seed(game_params
*params
, char *seed
)
1526 int area
= params
->r
* params
->r
* params
->c
* params
->c
;
1531 if (n
>= 'a' && n
<= 'z') {
1532 squares
+= n
- 'a' + 1;
1533 } else if (n
== '_') {
1535 } else if (n
> '0' && n
<= '9') {
1537 while (*seed
>= '0' && *seed
<= '9')
1540 return "Invalid character in game specification";
1544 return "Not enough data to fill grid";
1547 return "Too much data to fit in grid";
1552 static game_state
*new_game(game_params
*params
, char *seed
)
1554 game_state
*state
= snew(game_state
);
1555 int c
= params
->c
, r
= params
->r
, cr
= c
*r
, area
= cr
* cr
;
1558 state
->c
= params
->c
;
1559 state
->r
= params
->r
;
1561 state
->grid
= snewn(area
, digit
);
1562 state
->immutable
= snewn(area
, unsigned char);
1563 memset(state
->immutable
, FALSE
, area
);
1565 state
->completed
= FALSE
;
1570 if (n
>= 'a' && n
<= 'z') {
1571 int run
= n
- 'a' + 1;
1572 assert(i
+ run
<= area
);
1574 state
->grid
[i
++] = 0;
1575 } else if (n
== '_') {
1577 } else if (n
> '0' && n
<= '9') {
1579 state
->immutable
[i
] = TRUE
;
1580 state
->grid
[i
++] = atoi(seed
-1);
1581 while (*seed
>= '0' && *seed
<= '9')
1584 assert(!"We can't get here");
1592 static game_state
*dup_game(game_state
*state
)
1594 game_state
*ret
= snew(game_state
);
1595 int c
= state
->c
, r
= state
->r
, cr
= c
*r
, area
= cr
* cr
;
1600 ret
->grid
= snewn(area
, digit
);
1601 memcpy(ret
->grid
, state
->grid
, area
);
1603 ret
->immutable
= snewn(area
, unsigned char);
1604 memcpy(ret
->immutable
, state
->immutable
, area
);
1606 ret
->completed
= state
->completed
;
1611 static void free_game(game_state
*state
)
1613 sfree(state
->immutable
);
1620 * These are the coordinates of the currently highlighted
1621 * square on the grid, or -1,-1 if there isn't one. When there
1622 * is, pressing a valid number or letter key or Space will
1623 * enter that number or letter in the grid.
1628 static game_ui
*new_ui(game_state
*state
)
1630 game_ui
*ui
= snew(game_ui
);
1632 ui
->hx
= ui
->hy
= -1;
1637 static void free_ui(game_ui
*ui
)
1642 static game_state
*make_move(game_state
*from
, game_ui
*ui
, int x
, int y
,
1645 int c
= from
->c
, r
= from
->r
, cr
= c
*r
;
1649 tx
= (x
+ TILE_SIZE
- BORDER
) / TILE_SIZE
- 1;
1650 ty
= (y
+ TILE_SIZE
- BORDER
) / TILE_SIZE
- 1;
1652 if (tx
>= 0 && tx
< cr
&& ty
>= 0 && ty
< cr
&& button
== LEFT_BUTTON
) {
1653 if (tx
== ui
->hx
&& ty
== ui
->hy
) {
1654 ui
->hx
= ui
->hy
= -1;
1659 return from
; /* UI activity occurred */
1662 if (ui
->hx
!= -1 && ui
->hy
!= -1 &&
1663 ((button
>= '1' && button
<= '9' && button
- '0' <= cr
) ||
1664 (button
>= 'a' && button
<= 'z' && button
- 'a' + 10 <= cr
) ||
1665 (button
>= 'A' && button
<= 'Z' && button
- 'A' + 10 <= cr
) ||
1667 int n
= button
- '0';
1668 if (button
>= 'A' && button
<= 'Z')
1669 n
= button
- 'A' + 10;
1670 if (button
>= 'a' && button
<= 'z')
1671 n
= button
- 'a' + 10;
1675 if (from
->immutable
[ui
->hy
*cr
+ui
->hx
])
1676 return NULL
; /* can't overwrite this square */
1678 ret
= dup_game(from
);
1679 ret
->grid
[ui
->hy
*cr
+ui
->hx
] = n
;
1680 ui
->hx
= ui
->hy
= -1;
1683 * We've made a real change to the grid. Check to see
1684 * if the game has been completed.
1686 if (!ret
->completed
&& check_valid(c
, r
, ret
->grid
)) {
1687 ret
->completed
= TRUE
;
1690 return ret
; /* made a valid move */
1696 /* ----------------------------------------------------------------------
1700 struct game_drawstate
{
1707 #define XSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1708 #define YSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1710 static void game_size(game_params
*params
, int *x
, int *y
)
1712 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1718 static float *game_colours(frontend
*fe
, game_state
*state
, int *ncolours
)
1720 float *ret
= snewn(3 * NCOLOURS
, float);
1722 frontend_default_colour(fe
, &ret
[COL_BACKGROUND
* 3]);
1724 ret
[COL_GRID
* 3 + 0] = 0.0F
;
1725 ret
[COL_GRID
* 3 + 1] = 0.0F
;
1726 ret
[COL_GRID
* 3 + 2] = 0.0F
;
1728 ret
[COL_CLUE
* 3 + 0] = 0.0F
;
1729 ret
[COL_CLUE
* 3 + 1] = 0.0F
;
1730 ret
[COL_CLUE
* 3 + 2] = 0.0F
;
1732 ret
[COL_USER
* 3 + 0] = 0.0F
;
1733 ret
[COL_USER
* 3 + 1] = 0.6F
* ret
[COL_BACKGROUND
* 3 + 1];
1734 ret
[COL_USER
* 3 + 2] = 0.0F
;
1736 ret
[COL_HIGHLIGHT
* 3 + 0] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 0];
1737 ret
[COL_HIGHLIGHT
* 3 + 1] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 1];
1738 ret
[COL_HIGHLIGHT
* 3 + 2] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 2];
1740 *ncolours
= NCOLOURS
;
1744 static game_drawstate
*game_new_drawstate(game_state
*state
)
1746 struct game_drawstate
*ds
= snew(struct game_drawstate
);
1747 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1749 ds
->started
= FALSE
;
1753 ds
->grid
= snewn(cr
*cr
, digit
);
1754 memset(ds
->grid
, 0, cr
*cr
);
1755 ds
->hl
= snewn(cr
*cr
, unsigned char);
1756 memset(ds
->hl
, 0, cr
*cr
);
1761 static void game_free_drawstate(game_drawstate
*ds
)
1768 static void draw_number(frontend
*fe
, game_drawstate
*ds
, game_state
*state
,
1769 int x
, int y
, int hl
)
1771 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1776 if (ds
->grid
[y
*cr
+x
] == state
->grid
[y
*cr
+x
] && ds
->hl
[y
*cr
+x
] == hl
)
1777 return; /* no change required */
1779 tx
= BORDER
+ x
* TILE_SIZE
+ 2;
1780 ty
= BORDER
+ y
* TILE_SIZE
+ 2;
1796 clip(fe
, cx
, cy
, cw
, ch
);
1798 /* background needs erasing? */
1799 if (ds
->grid
[y
*cr
+x
] || ds
->hl
[y
*cr
+x
] != hl
)
1800 draw_rect(fe
, cx
, cy
, cw
, ch
, hl ? COL_HIGHLIGHT
: COL_BACKGROUND
);
1802 /* new number needs drawing? */
1803 if (state
->grid
[y
*cr
+x
]) {
1805 str
[0] = state
->grid
[y
*cr
+x
] + '0';
1807 str
[0] += 'a' - ('9'+1);
1808 draw_text(fe
, tx
+ TILE_SIZE
/2, ty
+ TILE_SIZE
/2,
1809 FONT_VARIABLE
, TILE_SIZE
/2, ALIGN_VCENTRE
| ALIGN_HCENTRE
,
1810 state
->immutable
[y
*cr
+x
] ? COL_CLUE
: COL_USER
, str
);
1815 draw_update(fe
, cx
, cy
, cw
, ch
);
1817 ds
->grid
[y
*cr
+x
] = state
->grid
[y
*cr
+x
];
1818 ds
->hl
[y
*cr
+x
] = hl
;
1821 static void game_redraw(frontend
*fe
, game_drawstate
*ds
, game_state
*oldstate
,
1822 game_state
*state
, int dir
, game_ui
*ui
,
1823 float animtime
, float flashtime
)
1825 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1830 * The initial contents of the window are not guaranteed
1831 * and can vary with front ends. To be on the safe side,
1832 * all games should start by drawing a big
1833 * background-colour rectangle covering the whole window.
1835 draw_rect(fe
, 0, 0, XSIZE(cr
), YSIZE(cr
), COL_BACKGROUND
);
1840 for (x
= 0; x
<= cr
; x
++) {
1841 int thick
= (x
% r ?
0 : 1);
1842 draw_rect(fe
, BORDER
+ x
*TILE_SIZE
- thick
, BORDER
-1,
1843 1+2*thick
, cr
*TILE_SIZE
+3, COL_GRID
);
1845 for (y
= 0; y
<= cr
; y
++) {
1846 int thick
= (y
% c ?
0 : 1);
1847 draw_rect(fe
, BORDER
-1, BORDER
+ y
*TILE_SIZE
- thick
,
1848 cr
*TILE_SIZE
+3, 1+2*thick
, COL_GRID
);
1853 * Draw any numbers which need redrawing.
1855 for (x
= 0; x
< cr
; x
++) {
1856 for (y
= 0; y
< cr
; y
++) {
1857 draw_number(fe
, ds
, state
, x
, y
,
1858 (x
== ui
->hx
&& y
== ui
->hy
) ||
1860 (flashtime
<= FLASH_TIME
/3 ||
1861 flashtime
>= FLASH_TIME
*2/3)));
1866 * Update the _entire_ grid if necessary.
1869 draw_update(fe
, 0, 0, XSIZE(cr
), YSIZE(cr
));
1874 static float game_anim_length(game_state
*oldstate
, game_state
*newstate
,
1880 static float game_flash_length(game_state
*oldstate
, game_state
*newstate
,
1883 if (!oldstate
->completed
&& newstate
->completed
)
1888 static int game_wants_statusbar(void)
1894 #define thegame solo
1897 const struct game thegame
= {
1898 "Solo", "games.solo", TRUE
,
1919 game_free_drawstate
,
1923 game_wants_statusbar
,
1926 #ifdef STANDALONE_SOLVER
1929 * gcc -DSTANDALONE_SOLVER -o solosolver solo.c malloc.c
1932 void frontend_default_colour(frontend
*fe
, float *output
) {}
1933 void draw_text(frontend
*fe
, int x
, int y
, int fonttype
, int fontsize
,
1934 int align
, int colour
, char *text
) {}
1935 void draw_rect(frontend
*fe
, int x
, int y
, int w
, int h
, int colour
) {}
1936 void draw_line(frontend
*fe
, int x1
, int y1
, int x2
, int y2
, int colour
) {}
1937 void draw_polygon(frontend
*fe
, int *coords
, int npoints
,
1938 int fill
, int colour
) {}
1939 void clip(frontend
*fe
, int x
, int y
, int w
, int h
) {}
1940 void unclip(frontend
*fe
) {}
1941 void start_draw(frontend
*fe
) {}
1942 void draw_update(frontend
*fe
, int x
, int y
, int w
, int h
) {}
1943 void end_draw(frontend
*fe
) {}
1944 unsigned long random_bits(random_state
*state
, int bits
)
1945 { assert(!"Shouldn't get randomness"); return 0; }
1946 unsigned long random_upto(random_state
*state
, unsigned long limit
)
1947 { assert(!"Shouldn't get randomness"); return 0; }
1949 void fatal(char *fmt
, ...)
1953 fprintf(stderr
, "fatal error: ");
1956 vfprintf(stderr
, fmt
, ap
);
1959 fprintf(stderr
, "\n");
1963 int main(int argc
, char **argv
)
1968 char *id
= NULL
, *seed
, *err
;
1972 while (--argc
> 0) {
1974 if (!strcmp(p
, "-r")) {
1976 } else if (!strcmp(p
, "-n")) {
1978 } else if (!strcmp(p
, "-v")) {
1979 solver_show_working
= TRUE
;
1981 } else if (!strcmp(p
, "-g")) {
1984 } else if (*p
== '-') {
1985 fprintf(stderr
, "%s: unrecognised option `%s'\n", argv
[0]);
1993 fprintf(stderr
, "usage: %s [-n | -r | -g | -v] <game_id>\n", argv
[0]);
1997 seed
= strchr(id
, ':');
1999 fprintf(stderr
, "%s: game id expects a colon in it\n", argv
[0]);
2004 p
= decode_params(id
);
2005 err
= validate_seed(p
, seed
);
2007 fprintf(stderr
, "%s: %s\n", argv
[0], err
);
2010 s
= new_game(p
, seed
);
2013 int ret
= rsolve(p
->c
, p
->r
, s
->grid
, NULL
, 2);
2015 fprintf(stderr
, "%s: rsolve: multiple solutions detected\n",
2019 int ret
= nsolve(p
->c
, p
->r
, s
->grid
);
2021 if (ret
== DIFF_IMPOSSIBLE
) {
2023 * Now resort to rsolve to determine whether it's
2026 ret
= rsolve(p
->c
, p
->r
, s
->grid
, NULL
, 2);
2028 ret
= DIFF_IMPOSSIBLE
;
2030 ret
= DIFF_RECURSIVE
;
2032 ret
= DIFF_AMBIGUOUS
;
2034 printf("difficulty rating: %s\n",
2035 ret
==DIFF_BLOCK ?
"blockwise positional elimination only":
2036 ret
==DIFF_SIMPLE ?
"row/column/number elimination required":
2037 ret
==DIFF_INTERSECT ?
"intersectional analysis required":
2038 ret
==DIFF_SET ?
"set elimination required":
2039 ret
==DIFF_RECURSIVE ?
"guesswork and backtracking required":
2040 ret
==DIFF_AMBIGUOUS ?
"multiple solutions exist":
2041 ret
==DIFF_IMPOSSIBLE ?
"no solution exists":
2042 "INTERNAL ERROR: unrecognised difficulty code");
2046 for (y
= 0; y
< p
->c
* p
->r
; y
++) {
2047 for (x
= 0; x
< p
->c
* p
->r
; x
++) {
2048 int c
= s
->grid
[y
* p
->c
* p
->r
+ x
];
2056 if (x
+1 < p
->c
* p
->r
) {
2064 if (y
+1 < p
->c
* p
->r
&& (y
+1) % p
->r
== 0) {
2065 for (x
= 0; x
< p
->c
* p
->r
; x
++) {
2067 if (x
+1 < p
->c
* p
->r
) {