2 * solo.c: the number-placing puzzle most popularly known as `Sudoku'.
6 * - it might still be nice to do some prioritisation on the
7 * removal of numbers from the grid
8 * + one possibility is to try to minimise the maximum number
9 * of filled squares in any block, which in particular ought
10 * to enforce never leaving a completely filled block in the
11 * puzzle as presented.
13 * - alternative interface modes
14 * + sudoku.com's Windows program has a palette of possible
15 * entries; you select a palette entry first and then click
16 * on the square you want it to go in, thus enabling
17 * mouse-only play. Useful for PDAs! I don't think it's
18 * actually incompatible with the current highlight-then-type
19 * approach: you _either_ highlight a palette entry and then
20 * click, _or_ you highlight a square and then type. At most
21 * one thing is ever highlighted at a time, so there's no way
23 * + `pencil marks' might be useful for more subtle forms of
24 * deduction, now we can create puzzles that require them.
28 * Solo puzzles need to be square overall (since each row and each
29 * column must contain one of every digit), but they need not be
30 * subdivided the same way internally. I am going to adopt a
31 * convention whereby I _always_ refer to `r' as the number of rows
32 * of _big_ divisions, and `c' as the number of columns of _big_
33 * divisions. Thus, a 2c by 3r puzzle looks something like this:
37 * ------+------ (Of course, you can't subdivide it the other way
38 * 1 4 5 | 6 3 2 or you'll get clashes; observe that the 4 in the
39 * 3 2 6 | 4 1 5 top left would conflict with the 4 in the second
40 * ------+------ box down on the left-hand side.)
44 * The need for a strong naming convention should now be clear:
45 * each small box is two rows of digits by three columns, while the
46 * overall puzzle has three rows of small boxes by two columns. So
47 * I will (hopefully) consistently use `r' to denote the number of
48 * rows _of small boxes_ (here 3), which is also the number of
49 * columns of digits in each small box; and `c' vice versa (here
52 * I'm also going to choose arbitrarily to list c first wherever
53 * possible: the above is a 2x3 puzzle, not a 3x2 one.
63 #ifdef STANDALONE_SOLVER
65 int solver_show_working
;
70 #define max(x,y) ((x)>(y)?(x):(y))
73 * To save space, I store digits internally as unsigned char. This
74 * imposes a hard limit of 255 on the order of the puzzle. Since
75 * even a 5x5 takes unacceptably long to generate, I don't see this
76 * as a serious limitation unless something _really_ impressive
77 * happens in computing technology; but here's a typedef anyway for
78 * general good practice.
80 typedef unsigned char digit
;
86 #define FLASH_TIME 0.4F
88 enum { SYMM_NONE
, SYMM_ROT2
, SYMM_ROT4
, SYMM_REF4
};
90 enum { DIFF_BLOCK
, DIFF_SIMPLE
, DIFF_INTERSECT
,
91 DIFF_SET
, DIFF_RECURSIVE
, DIFF_AMBIGUOUS
, DIFF_IMPOSSIBLE
};
103 int c
, r
, symm
, diff
;
109 unsigned char *immutable
; /* marks which digits are clues */
110 int completed
, cheated
;
113 static game_params
*default_params(void)
115 game_params
*ret
= snew(game_params
);
118 ret
->symm
= SYMM_ROT2
; /* a plausible default */
119 ret
->diff
= DIFF_SIMPLE
; /* so is this */
124 static void free_params(game_params
*params
)
129 static game_params
*dup_params(game_params
*params
)
131 game_params
*ret
= snew(game_params
);
132 *ret
= *params
; /* structure copy */
136 static int game_fetch_preset(int i
, char **name
, game_params
**params
)
142 { "2x2 Trivial", { 2, 2, SYMM_ROT2
, DIFF_BLOCK
} },
143 { "2x3 Basic", { 2, 3, SYMM_ROT2
, DIFF_SIMPLE
} },
144 { "3x3 Basic", { 3, 3, SYMM_ROT2
, DIFF_SIMPLE
} },
145 { "3x3 Intermediate", { 3, 3, SYMM_ROT2
, DIFF_INTERSECT
} },
146 { "3x3 Advanced", { 3, 3, SYMM_ROT2
, DIFF_SET
} },
147 { "3x4 Basic", { 3, 4, SYMM_ROT2
, DIFF_SIMPLE
} },
148 { "4x4 Basic", { 4, 4, SYMM_ROT2
, DIFF_SIMPLE
} },
151 if (i
< 0 || i
>= lenof(presets
))
154 *name
= dupstr(presets
[i
].title
);
155 *params
= dup_params(&presets
[i
].params
);
160 static game_params
*decode_params(char const *string
)
162 game_params
*ret
= default_params();
164 ret
->c
= ret
->r
= atoi(string
);
165 ret
->symm
= SYMM_ROT2
;
166 while (*string
&& isdigit((unsigned char)*string
)) string
++;
167 if (*string
== 'x') {
169 ret
->r
= atoi(string
);
170 while (*string
&& isdigit((unsigned char)*string
)) string
++;
173 if (*string
== 'r' || *string
== 'm' || *string
== 'a') {
177 while (*string
&& isdigit((unsigned char)*string
)) string
++;
178 if (sc
== 'm' && sn
== 4)
179 ret
->symm
= SYMM_REF4
;
180 if (sc
== 'r' && sn
== 4)
181 ret
->symm
= SYMM_ROT4
;
182 if (sc
== 'r' && sn
== 2)
183 ret
->symm
= SYMM_ROT2
;
185 ret
->symm
= SYMM_NONE
;
186 } else if (*string
== 'd') {
188 if (*string
== 't') /* trivial */
189 string
++, ret
->diff
= DIFF_BLOCK
;
190 else if (*string
== 'b') /* basic */
191 string
++, ret
->diff
= DIFF_SIMPLE
;
192 else if (*string
== 'i') /* intermediate */
193 string
++, ret
->diff
= DIFF_INTERSECT
;
194 else if (*string
== 'a') /* advanced */
195 string
++, ret
->diff
= DIFF_SET
;
197 string
++; /* eat unknown character */
203 static char *encode_params(game_params
*params
)
208 * Symmetry is a game generation preference and hence is left
209 * out of the encoding. Users can add it back in as they see
212 sprintf(str
, "%dx%d", params
->c
, params
->r
);
216 static config_item
*game_configure(game_params
*params
)
221 ret
= snewn(5, config_item
);
223 ret
[0].name
= "Columns of sub-blocks";
224 ret
[0].type
= C_STRING
;
225 sprintf(buf
, "%d", params
->c
);
226 ret
[0].sval
= dupstr(buf
);
229 ret
[1].name
= "Rows of sub-blocks";
230 ret
[1].type
= C_STRING
;
231 sprintf(buf
, "%d", params
->r
);
232 ret
[1].sval
= dupstr(buf
);
235 ret
[2].name
= "Symmetry";
236 ret
[2].type
= C_CHOICES
;
237 ret
[2].sval
= ":None:2-way rotation:4-way rotation:4-way mirror";
238 ret
[2].ival
= params
->symm
;
240 ret
[3].name
= "Difficulty";
241 ret
[3].type
= C_CHOICES
;
242 ret
[3].sval
= ":Trivial:Basic:Intermediate:Advanced";
243 ret
[3].ival
= params
->diff
;
253 static game_params
*custom_params(config_item
*cfg
)
255 game_params
*ret
= snew(game_params
);
257 ret
->c
= atoi(cfg
[0].sval
);
258 ret
->r
= atoi(cfg
[1].sval
);
259 ret
->symm
= cfg
[2].ival
;
260 ret
->diff
= cfg
[3].ival
;
265 static char *validate_params(game_params
*params
)
267 if (params
->c
< 2 || params
->r
< 2)
268 return "Both dimensions must be at least 2";
269 if (params
->c
> ORDER_MAX
|| params
->r
> ORDER_MAX
)
270 return "Dimensions greater than "STR(ORDER_MAX
)" are not supported";
274 /* ----------------------------------------------------------------------
275 * Full recursive Solo solver.
277 * The algorithm for this solver is shamelessly copied from a
278 * Python solver written by Andrew Wilkinson (which is GPLed, but
279 * I've reused only ideas and no code). It mostly just does the
280 * obvious recursive thing: pick an empty square, put one of the
281 * possible digits in it, recurse until all squares are filled,
282 * backtrack and change some choices if necessary.
284 * The clever bit is that every time it chooses which square to
285 * fill in next, it does so by counting the number of _possible_
286 * numbers that can go in each square, and it prioritises so that
287 * it picks a square with the _lowest_ number of possibilities. The
288 * idea is that filling in lots of the obvious bits (particularly
289 * any squares with only one possibility) will cut down on the list
290 * of possibilities for other squares and hence reduce the enormous
291 * search space as much as possible as early as possible.
293 * In practice the algorithm appeared to work very well; run on
294 * sample problems from the Times it completed in well under a
295 * second on my G5 even when written in Python, and given an empty
296 * grid (so that in principle it would enumerate _all_ solved
297 * grids!) it found the first valid solution just as quickly. So
298 * with a bit more randomisation I see no reason not to use this as
303 * Internal data structure used in solver to keep track of
306 struct rsolve_coord
{ int x
, y
, r
; };
307 struct rsolve_usage
{
308 int c
, r
, cr
; /* cr == c*r */
309 /* grid is a copy of the input grid, modified as we go along */
311 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
313 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
315 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
317 /* This lists all the empty spaces remaining in the grid. */
318 struct rsolve_coord
*spaces
;
320 /* If we need randomisation in the solve, this is our random state. */
322 /* Number of solutions so far found, and maximum number we care about. */
327 * The real recursive step in the solving function.
329 static void rsolve_real(struct rsolve_usage
*usage
, digit
*grid
)
331 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
332 int i
, j
, n
, sx
, sy
, bestm
, bestr
;
336 * Firstly, check for completion! If there are no spaces left
337 * in the grid, we have a solution.
339 if (usage
->nspaces
== 0) {
342 * This is our first solution, so fill in the output grid.
344 memcpy(grid
, usage
->grid
, cr
* cr
);
351 * Otherwise, there must be at least one space. Find the most
352 * constrained space, using the `r' field as a tie-breaker.
354 bestm
= cr
+1; /* so that any space will beat it */
357 for (j
= 0; j
< usage
->nspaces
; j
++) {
358 int x
= usage
->spaces
[j
].x
, y
= usage
->spaces
[j
].y
;
362 * Find the number of digits that could go in this space.
365 for (n
= 0; n
< cr
; n
++)
366 if (!usage
->row
[y
*cr
+n
] && !usage
->col
[x
*cr
+n
] &&
367 !usage
->blk
[((y
/c
)*c
+(x
/r
))*cr
+n
])
370 if (m
< bestm
|| (m
== bestm
&& usage
->spaces
[j
].r
< bestr
)) {
372 bestr
= usage
->spaces
[j
].r
;
380 * Swap that square into the final place in the spaces array,
381 * so that decrementing nspaces will remove it from the list.
383 if (i
!= usage
->nspaces
-1) {
384 struct rsolve_coord t
;
385 t
= usage
->spaces
[usage
->nspaces
-1];
386 usage
->spaces
[usage
->nspaces
-1] = usage
->spaces
[i
];
387 usage
->spaces
[i
] = t
;
391 * Now we've decided which square to start our recursion at,
392 * simply go through all possible values, shuffling them
393 * randomly first if necessary.
395 digits
= snewn(bestm
, int);
397 for (n
= 0; n
< cr
; n
++)
398 if (!usage
->row
[sy
*cr
+n
] && !usage
->col
[sx
*cr
+n
] &&
399 !usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
]) {
405 for (i
= j
; i
> 1; i
--) {
406 int p
= random_upto(usage
->rs
, i
);
409 digits
[p
] = digits
[i
-1];
415 /* And finally, go through the digit list and actually recurse. */
416 for (i
= 0; i
< j
; i
++) {
419 /* Update the usage structure to reflect the placing of this digit. */
420 usage
->row
[sy
*cr
+n
-1] = usage
->col
[sx
*cr
+n
-1] =
421 usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
-1] = TRUE
;
422 usage
->grid
[sy
*cr
+sx
] = n
;
425 /* Call the solver recursively. */
426 rsolve_real(usage
, grid
);
429 * If we have seen as many solutions as we need, terminate
430 * all processing immediately.
432 if (usage
->solns
>= usage
->maxsolns
)
435 /* Revert the usage structure. */
436 usage
->row
[sy
*cr
+n
-1] = usage
->col
[sx
*cr
+n
-1] =
437 usage
->blk
[((sy
/c
)*c
+(sx
/r
))*cr
+n
-1] = FALSE
;
438 usage
->grid
[sy
*cr
+sx
] = 0;
446 * Entry point to solver. You give it dimensions and a starting
447 * grid, which is simply an array of N^4 digits. In that array, 0
448 * means an empty square, and 1..N mean a clue square.
450 * Return value is the number of solutions found; searching will
451 * stop after the provided `max'. (Thus, you can pass max==1 to
452 * indicate that you only care about finding _one_ solution, or
453 * max==2 to indicate that you want to know the difference between
454 * a unique and non-unique solution.) The input parameter `grid' is
455 * also filled in with the _first_ (or only) solution found by the
458 static int rsolve(int c
, int r
, digit
*grid
, random_state
*rs
, int max
)
460 struct rsolve_usage
*usage
;
465 * Create an rsolve_usage structure.
467 usage
= snew(struct rsolve_usage
);
473 usage
->grid
= snewn(cr
* cr
, digit
);
474 memcpy(usage
->grid
, grid
, cr
* cr
);
476 usage
->row
= snewn(cr
* cr
, unsigned char);
477 usage
->col
= snewn(cr
* cr
, unsigned char);
478 usage
->blk
= snewn(cr
* cr
, unsigned char);
479 memset(usage
->row
, FALSE
, cr
* cr
);
480 memset(usage
->col
, FALSE
, cr
* cr
);
481 memset(usage
->blk
, FALSE
, cr
* cr
);
483 usage
->spaces
= snewn(cr
* cr
, struct rsolve_coord
);
487 usage
->maxsolns
= max
;
492 * Now fill it in with data from the input grid.
494 for (y
= 0; y
< cr
; y
++) {
495 for (x
= 0; x
< cr
; x
++) {
496 int v
= grid
[y
*cr
+x
];
498 usage
->spaces
[usage
->nspaces
].x
= x
;
499 usage
->spaces
[usage
->nspaces
].y
= y
;
501 usage
->spaces
[usage
->nspaces
].r
= random_bits(rs
, 31);
503 usage
->spaces
[usage
->nspaces
].r
= usage
->nspaces
;
506 usage
->row
[y
*cr
+v
-1] = TRUE
;
507 usage
->col
[x
*cr
+v
-1] = TRUE
;
508 usage
->blk
[((y
/c
)*c
+(x
/r
))*cr
+v
-1] = TRUE
;
514 * Run the real recursive solving function.
516 rsolve_real(usage
, grid
);
520 * Clean up the usage structure now we have our answer.
522 sfree(usage
->spaces
);
535 /* ----------------------------------------------------------------------
536 * End of recursive solver code.
539 /* ----------------------------------------------------------------------
540 * Less capable non-recursive solver. This one is used to check
541 * solubility of a grid as we gradually remove numbers from it: by
542 * verifying a grid using this solver we can ensure it isn't _too_
543 * hard (e.g. does not actually require guessing and backtracking).
545 * It supports a variety of specific modes of reasoning. By
546 * enabling or disabling subsets of these modes we can arrange a
547 * range of difficulty levels.
551 * Modes of reasoning currently supported:
553 * - Positional elimination: a number must go in a particular
554 * square because all the other empty squares in a given
555 * row/col/blk are ruled out.
557 * - Numeric elimination: a square must have a particular number
558 * in because all the other numbers that could go in it are
561 * - Intersectional analysis: given two domains which overlap
562 * (hence one must be a block, and the other can be a row or
563 * col), if the possible locations for a particular number in
564 * one of the domains can be narrowed down to the overlap, then
565 * that number can be ruled out everywhere but the overlap in
566 * the other domain too.
568 * - Set elimination: if there is a subset of the empty squares
569 * within a domain such that the union of the possible numbers
570 * in that subset has the same size as the subset itself, then
571 * those numbers can be ruled out everywhere else in the domain.
572 * (For example, if there are five empty squares and the
573 * possible numbers in each are 12, 23, 13, 134 and 1345, then
574 * the first three empty squares form such a subset: the numbers
575 * 1, 2 and 3 _must_ be in those three squares in some
576 * permutation, and hence we can deduce none of them can be in
577 * the fourth or fifth squares.)
578 * + You can also see this the other way round, concentrating
579 * on numbers rather than squares: if there is a subset of
580 * the unplaced numbers within a domain such that the union
581 * of all their possible positions has the same size as the
582 * subset itself, then all other numbers can be ruled out for
583 * those positions. However, it turns out that this is
584 * exactly equivalent to the first formulation at all times:
585 * there is a 1-1 correspondence between suitable subsets of
586 * the unplaced numbers and suitable subsets of the unfilled
587 * places, found by taking the _complement_ of the union of
588 * the numbers' possible positions (or the spaces' possible
593 * Within this solver, I'm going to transform all y-coordinates by
594 * inverting the significance of the block number and the position
595 * within the block. That is, we will start with the top row of
596 * each block in order, then the second row of each block in order,
599 * This transformation has the enormous advantage that it means
600 * every row, column _and_ block is described by an arithmetic
601 * progression of coordinates within the cubic array, so that I can
602 * use the same very simple function to do blockwise, row-wise and
603 * column-wise elimination.
605 #define YTRANS(y) (((y)%c)*r+(y)/c)
606 #define YUNTRANS(y) (((y)%r)*c+(y)/r)
608 struct nsolve_usage
{
611 * We set up a cubic array, indexed by x, y and digit; each
612 * element of this array is TRUE or FALSE according to whether
613 * or not that digit _could_ in principle go in that position.
615 * The way to index this array is cube[(x*cr+y)*cr+n-1].
616 * y-coordinates in here are transformed.
620 * This is the grid in which we write down our final
621 * deductions. y-coordinates in here are _not_ transformed.
625 * Now we keep track, at a slightly higher level, of what we
626 * have yet to work out, to prevent doing the same deduction
629 /* row[y*cr+n-1] TRUE if digit n has been placed in row y */
631 /* col[x*cr+n-1] TRUE if digit n has been placed in row x */
633 /* blk[(y*c+x)*cr+n-1] TRUE if digit n has been placed in block (x,y) */
636 #define cubepos(x,y,n) (((x)*usage->cr+(y))*usage->cr+(n)-1)
637 #define cube(x,y,n) (usage->cube[cubepos(x,y,n)])
640 * Function called when we are certain that a particular square has
641 * a particular number in it. The y-coordinate passed in here is
644 static void nsolve_place(struct nsolve_usage
*usage
, int x
, int y
, int n
)
646 int c
= usage
->c
, r
= usage
->r
, cr
= usage
->cr
;
652 * Rule out all other numbers in this square.
654 for (i
= 1; i
<= cr
; i
++)
659 * Rule out this number in all other positions in the row.
661 for (i
= 0; i
< cr
; i
++)
666 * Rule out this number in all other positions in the column.
668 for (i
= 0; i
< cr
; i
++)
673 * Rule out this number in all other positions in the block.
677 for (i
= 0; i
< r
; i
++)
678 for (j
= 0; j
< c
; j
++)
679 if (bx
+i
!= x
|| by
+j
*r
!= y
)
680 cube(bx
+i
,by
+j
*r
,n
) = FALSE
;
683 * Enter the number in the result grid.
685 usage
->grid
[YUNTRANS(y
)*cr
+x
] = n
;
688 * Cross out this number from the list of numbers left to place
689 * in its row, its column and its block.
691 usage
->row
[y
*cr
+n
-1] = usage
->col
[x
*cr
+n
-1] =
692 usage
->blk
[((y
%r
)*c
+(x
/r
))*cr
+n
-1] = TRUE
;
695 static int nsolve_elim(struct nsolve_usage
*usage
, int start
, int step
696 #ifdef STANDALONE_SOLVER
701 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
705 * Count the number of set bits within this section of the
710 for (i
= 0; i
< cr
; i
++)
711 if (usage
->cube
[start
+i
*step
]) {
725 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
]) {
726 #ifdef STANDALONE_SOLVER
727 if (solver_show_working
) {
732 printf(":\n placing %d at (%d,%d)\n",
733 n
, 1+x
, 1+YUNTRANS(y
));
736 nsolve_place(usage
, x
, y
, n
);
744 static int nsolve_intersect(struct nsolve_usage
*usage
,
745 int start1
, int step1
, int start2
, int step2
746 #ifdef STANDALONE_SOLVER
751 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
755 * Loop over the first domain and see if there's any set bit
756 * not also in the second.
758 for (i
= 0; i
< cr
; i
++) {
759 int p
= start1
+i
*step1
;
760 if (usage
->cube
[p
] &&
761 !(p
>= start2
&& p
< start2
+cr
*step2
&&
762 (p
- start2
) % step2
== 0))
763 return FALSE
; /* there is, so we can't deduce */
767 * We have determined that all set bits in the first domain are
768 * within its overlap with the second. So loop over the second
769 * domain and remove all set bits that aren't also in that
770 * overlap; return TRUE iff we actually _did_ anything.
773 for (i
= 0; i
< cr
; i
++) {
774 int p
= start2
+i
*step2
;
775 if (usage
->cube
[p
] &&
776 !(p
>= start1
&& p
< start1
+cr
*step1
&& (p
- start1
) % step1
== 0))
778 #ifdef STANDALONE_SOLVER
779 if (solver_show_working
) {
795 printf(" ruling out %d at (%d,%d)\n",
796 pn
, 1+px
, 1+YUNTRANS(py
));
799 ret
= TRUE
; /* we did something */
807 static int nsolve_set(struct nsolve_usage
*usage
,
808 int start
, int step1
, int step2
809 #ifdef STANDALONE_SOLVER
814 int c
= usage
->c
, r
= usage
->r
, cr
= c
*r
;
816 unsigned char *grid
= snewn(cr
*cr
, unsigned char);
817 unsigned char *rowidx
= snewn(cr
, unsigned char);
818 unsigned char *colidx
= snewn(cr
, unsigned char);
819 unsigned char *set
= snewn(cr
, unsigned char);
822 * We are passed a cr-by-cr matrix of booleans. Our first job
823 * is to winnow it by finding any definite placements - i.e.
824 * any row with a solitary 1 - and discarding that row and the
825 * column containing the 1.
827 memset(rowidx
, TRUE
, cr
);
828 memset(colidx
, TRUE
, cr
);
829 for (i
= 0; i
< cr
; i
++) {
830 int count
= 0, first
= -1;
831 for (j
= 0; j
< cr
; j
++)
832 if (usage
->cube
[start
+i
*step1
+j
*step2
])
836 * This condition actually marks a completely insoluble
837 * (i.e. internally inconsistent) puzzle. We return and
838 * report no progress made.
843 rowidx
[i
] = colidx
[first
] = FALSE
;
847 * Convert each of rowidx/colidx from a list of 0s and 1s to a
848 * list of the indices of the 1s.
850 for (i
= j
= 0; i
< cr
; i
++)
854 for (i
= j
= 0; i
< cr
; i
++)
860 * And create the smaller matrix.
862 for (i
= 0; i
< n
; i
++)
863 for (j
= 0; j
< n
; j
++)
864 grid
[i
*cr
+j
] = usage
->cube
[start
+rowidx
[i
]*step1
+colidx
[j
]*step2
];
867 * Having done that, we now have a matrix in which every row
868 * has at least two 1s in. Now we search to see if we can find
869 * a rectangle of zeroes (in the set-theoretic sense of
870 * `rectangle', i.e. a subset of rows crossed with a subset of
871 * columns) whose width and height add up to n.
878 * We have a candidate set. If its size is <=1 or >=n-1
879 * then we move on immediately.
881 if (count
> 1 && count
< n
-1) {
883 * The number of rows we need is n-count. See if we can
884 * find that many rows which each have a zero in all
885 * the positions listed in `set'.
888 for (i
= 0; i
< n
; i
++) {
890 for (j
= 0; j
< n
; j
++)
891 if (set
[j
] && grid
[i
*cr
+j
]) {
900 * We expect never to be able to get _more_ than
901 * n-count suitable rows: this would imply that (for
902 * example) there are four numbers which between them
903 * have at most three possible positions, and hence it
904 * indicates a faulty deduction before this point or
907 assert(rows
<= n
- count
);
908 if (rows
>= n
- count
) {
909 int progress
= FALSE
;
912 * We've got one! Now, for each row which _doesn't_
913 * satisfy the criterion, eliminate all its set
914 * bits in the positions _not_ listed in `set'.
915 * Return TRUE (meaning progress has been made) if
916 * we successfully eliminated anything at all.
918 * This involves referring back through
919 * rowidx/colidx in order to work out which actual
920 * positions in the cube to meddle with.
922 for (i
= 0; i
< n
; i
++) {
924 for (j
= 0; j
< n
; j
++)
925 if (set
[j
] && grid
[i
*cr
+j
]) {
930 for (j
= 0; j
< n
; j
++)
931 if (!set
[j
] && grid
[i
*cr
+j
]) {
932 int fpos
= (start
+rowidx
[i
]*step1
+
934 #ifdef STANDALONE_SOLVER
935 if (solver_show_working
) {
951 printf(" ruling out %d at (%d,%d)\n",
952 pn
, 1+px
, 1+YUNTRANS(py
));
956 usage
->cube
[fpos
] = FALSE
;
972 * Binary increment: change the rightmost 0 to a 1, and
973 * change all 1s to the right of it to 0s.
976 while (i
> 0 && set
[i
-1])
977 set
[--i
] = 0, count
--;
979 set
[--i
] = 1, count
++;
992 static int nsolve(int c
, int r
, digit
*grid
)
994 struct nsolve_usage
*usage
;
997 int diff
= DIFF_BLOCK
;
1000 * Set up a usage structure as a clean slate (everything
1003 usage
= snew(struct nsolve_usage
);
1007 usage
->cube
= snewn(cr
*cr
*cr
, unsigned char);
1008 usage
->grid
= grid
; /* write straight back to the input */
1009 memset(usage
->cube
, TRUE
, cr
*cr
*cr
);
1011 usage
->row
= snewn(cr
* cr
, unsigned char);
1012 usage
->col
= snewn(cr
* cr
, unsigned char);
1013 usage
->blk
= snewn(cr
* cr
, unsigned char);
1014 memset(usage
->row
, FALSE
, cr
* cr
);
1015 memset(usage
->col
, FALSE
, cr
* cr
);
1016 memset(usage
->blk
, FALSE
, cr
* cr
);
1019 * Place all the clue numbers we are given.
1021 for (x
= 0; x
< cr
; x
++)
1022 for (y
= 0; y
< cr
; y
++)
1024 nsolve_place(usage
, x
, YTRANS(y
), grid
[y
*cr
+x
]);
1027 * Now loop over the grid repeatedly trying all permitted modes
1028 * of reasoning. The loop terminates if we complete an
1029 * iteration without making any progress; we then return
1030 * failure or success depending on whether the grid is full or
1035 * I'd like to write `continue;' inside each of the
1036 * following loops, so that the solver returns here after
1037 * making some progress. However, I can't specify that I
1038 * want to continue an outer loop rather than the innermost
1039 * one, so I'm apologetically resorting to a goto.
1044 * Blockwise positional elimination.
1046 for (x
= 0; x
< cr
; x
+= r
)
1047 for (y
= 0; y
< r
; y
++)
1048 for (n
= 1; n
<= cr
; n
++)
1049 if (!usage
->blk
[(y
*c
+(x
/r
))*cr
+n
-1] &&
1050 nsolve_elim(usage
, cubepos(x
,y
,n
), r
*cr
1051 #ifdef STANDALONE_SOLVER
1052 , "positional elimination,"
1053 " block (%d,%d)", 1+x
/r
, 1+y
1056 diff
= max(diff
, DIFF_BLOCK
);
1061 * Row-wise positional elimination.
1063 for (y
= 0; y
< cr
; y
++)
1064 for (n
= 1; n
<= cr
; n
++)
1065 if (!usage
->row
[y
*cr
+n
-1] &&
1066 nsolve_elim(usage
, cubepos(0,y
,n
), cr
*cr
1067 #ifdef STANDALONE_SOLVER
1068 , "positional elimination,"
1069 " row %d", 1+YUNTRANS(y
)
1072 diff
= max(diff
, DIFF_SIMPLE
);
1076 * Column-wise positional elimination.
1078 for (x
= 0; x
< cr
; x
++)
1079 for (n
= 1; n
<= cr
; n
++)
1080 if (!usage
->col
[x
*cr
+n
-1] &&
1081 nsolve_elim(usage
, cubepos(x
,0,n
), cr
1082 #ifdef STANDALONE_SOLVER
1083 , "positional elimination," " column %d", 1+x
1086 diff
= max(diff
, DIFF_SIMPLE
);
1091 * Numeric elimination.
1093 for (x
= 0; x
< cr
; x
++)
1094 for (y
= 0; y
< cr
; y
++)
1095 if (!usage
->grid
[YUNTRANS(y
)*cr
+x
] &&
1096 nsolve_elim(usage
, cubepos(x
,y
,1), 1
1097 #ifdef STANDALONE_SOLVER
1098 , "numeric elimination at (%d,%d)", 1+x
,
1102 diff
= max(diff
, DIFF_SIMPLE
);
1107 * Intersectional analysis, rows vs blocks.
1109 for (y
= 0; y
< cr
; y
++)
1110 for (x
= 0; x
< cr
; x
+= r
)
1111 for (n
= 1; n
<= cr
; n
++)
1112 if (!usage
->row
[y
*cr
+n
-1] &&
1113 !usage
->blk
[((y
%r
)*c
+(x
/r
))*cr
+n
-1] &&
1114 (nsolve_intersect(usage
, cubepos(0,y
,n
), cr
*cr
,
1115 cubepos(x
,y
%r
,n
), r
*cr
1116 #ifdef STANDALONE_SOLVER
1117 , "intersectional analysis,"
1118 " row %d vs block (%d,%d)",
1119 1+YUNTRANS(y
), 1+x
/r
, 1+y
%r
1122 nsolve_intersect(usage
, cubepos(x
,y
%r
,n
), r
*cr
,
1123 cubepos(0,y
,n
), cr
*cr
1124 #ifdef STANDALONE_SOLVER
1125 , "intersectional analysis,"
1126 " block (%d,%d) vs row %d",
1127 1+x
/r
, 1+y
%r
, 1+YUNTRANS(y
)
1130 diff
= max(diff
, DIFF_INTERSECT
);
1135 * Intersectional analysis, columns vs blocks.
1137 for (x
= 0; x
< cr
; x
++)
1138 for (y
= 0; y
< r
; y
++)
1139 for (n
= 1; n
<= cr
; n
++)
1140 if (!usage
->col
[x
*cr
+n
-1] &&
1141 !usage
->blk
[(y
*c
+(x
/r
))*cr
+n
-1] &&
1142 (nsolve_intersect(usage
, cubepos(x
,0,n
), cr
,
1143 cubepos((x
/r
)*r
,y
,n
), r
*cr
1144 #ifdef STANDALONE_SOLVER
1145 , "intersectional analysis,"
1146 " column %d vs block (%d,%d)",
1150 nsolve_intersect(usage
, cubepos((x
/r
)*r
,y
,n
), r
*cr
,
1152 #ifdef STANDALONE_SOLVER
1153 , "intersectional analysis,"
1154 " block (%d,%d) vs column %d",
1158 diff
= max(diff
, DIFF_INTERSECT
);
1163 * Blockwise set elimination.
1165 for (x
= 0; x
< cr
; x
+= r
)
1166 for (y
= 0; y
< r
; y
++)
1167 if (nsolve_set(usage
, cubepos(x
,y
,1), r
*cr
, 1
1168 #ifdef STANDALONE_SOLVER
1169 , "set elimination, block (%d,%d)", 1+x
/r
, 1+y
1172 diff
= max(diff
, DIFF_SET
);
1177 * Row-wise set elimination.
1179 for (y
= 0; y
< cr
; y
++)
1180 if (nsolve_set(usage
, cubepos(0,y
,1), cr
*cr
, 1
1181 #ifdef STANDALONE_SOLVER
1182 , "set elimination, row %d", 1+YUNTRANS(y
)
1185 diff
= max(diff
, DIFF_SET
);
1190 * Column-wise set elimination.
1192 for (x
= 0; x
< cr
; x
++)
1193 if (nsolve_set(usage
, cubepos(x
,0,1), cr
, 1
1194 #ifdef STANDALONE_SOLVER
1195 , "set elimination, column %d", 1+x
1198 diff
= max(diff
, DIFF_SET
);
1203 * If we reach here, we have made no deductions in this
1204 * iteration, so the algorithm terminates.
1215 for (x
= 0; x
< cr
; x
++)
1216 for (y
= 0; y
< cr
; y
++)
1218 return DIFF_IMPOSSIBLE
;
1222 /* ----------------------------------------------------------------------
1223 * End of non-recursive solver code.
1227 * Check whether a grid contains a valid complete puzzle.
1229 static int check_valid(int c
, int r
, digit
*grid
)
1232 unsigned char *used
;
1235 used
= snewn(cr
, unsigned char);
1238 * Check that each row contains precisely one of everything.
1240 for (y
= 0; y
< cr
; y
++) {
1241 memset(used
, FALSE
, cr
);
1242 for (x
= 0; x
< cr
; x
++)
1243 if (grid
[y
*cr
+x
] > 0 && grid
[y
*cr
+x
] <= cr
)
1244 used
[grid
[y
*cr
+x
]-1] = TRUE
;
1245 for (n
= 0; n
< cr
; n
++)
1253 * Check that each column contains precisely one of everything.
1255 for (x
= 0; x
< cr
; x
++) {
1256 memset(used
, FALSE
, cr
);
1257 for (y
= 0; y
< cr
; y
++)
1258 if (grid
[y
*cr
+x
] > 0 && grid
[y
*cr
+x
] <= cr
)
1259 used
[grid
[y
*cr
+x
]-1] = TRUE
;
1260 for (n
= 0; n
< cr
; n
++)
1268 * Check that each block contains precisely one of everything.
1270 for (x
= 0; x
< cr
; x
+= r
) {
1271 for (y
= 0; y
< cr
; y
+= c
) {
1273 memset(used
, FALSE
, cr
);
1274 for (xx
= x
; xx
< x
+r
; xx
++)
1275 for (yy
= 0; yy
< y
+c
; yy
++)
1276 if (grid
[yy
*cr
+xx
] > 0 && grid
[yy
*cr
+xx
] <= cr
)
1277 used
[grid
[yy
*cr
+xx
]-1] = TRUE
;
1278 for (n
= 0; n
< cr
; n
++)
1290 static void symmetry_limit(game_params
*params
, int *xlim
, int *ylim
, int s
)
1292 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1304 *xlim
= *ylim
= (cr
+1) / 2;
1309 static int symmetries(game_params
*params
, int x
, int y
, int *output
, int s
)
1311 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1320 break; /* just x,y is all we need */
1325 *output
++ = cr
- 1 - x
;
1330 *output
++ = cr
- 1 - y
;
1334 *output
++ = cr
- 1 - y
;
1339 *output
++ = cr
- 1 - x
;
1345 *output
++ = cr
- 1 - x
;
1346 *output
++ = cr
- 1 - y
;
1354 static char *new_game_seed(game_params
*params
, random_state
*rs
,
1355 game_aux_info
**aux
)
1357 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1359 digit
*grid
, *grid2
;
1360 struct xy
{ int x
, y
; } *locs
;
1364 int coords
[16], ncoords
;
1369 * Adjust the maximum difficulty level to be consistent with
1370 * the puzzle size: all 2x2 puzzles appear to be Trivial
1371 * (DIFF_BLOCK) so we cannot hold out for even a Basic
1372 * (DIFF_SIMPLE) one.
1374 maxdiff
= params
->diff
;
1375 if (c
== 2 && r
== 2)
1376 maxdiff
= DIFF_BLOCK
;
1378 grid
= snewn(area
, digit
);
1379 locs
= snewn(area
, struct xy
);
1380 grid2
= snewn(area
, digit
);
1383 * Loop until we get a grid of the required difficulty. This is
1384 * nasty, but it seems to be unpleasantly hard to generate
1385 * difficult grids otherwise.
1389 * Start the recursive solver with an empty grid to generate a
1390 * random solved state.
1392 memset(grid
, 0, area
);
1393 ret
= rsolve(c
, r
, grid
, rs
, 1);
1395 assert(check_valid(c
, r
, grid
));
1398 * Now we have a solved grid, start removing things from it
1399 * while preserving solubility.
1401 symmetry_limit(params
, &xlim
, &ylim
, params
->symm
);
1406 * Iterate over the grid and enumerate all the filled
1407 * squares we could empty.
1411 for (x
= 0; x
< xlim
; x
++)
1412 for (y
= 0; y
< ylim
; y
++)
1420 * Now shuffle that list.
1422 for (i
= nlocs
; i
> 1; i
--) {
1423 int p
= random_upto(rs
, i
);
1425 struct xy t
= locs
[p
];
1426 locs
[p
] = locs
[i
-1];
1432 * Now loop over the shuffled list and, for each element,
1433 * see whether removing that element (and its reflections)
1434 * from the grid will still leave the grid soluble by
1437 for (i
= 0; i
< nlocs
; i
++) {
1441 memcpy(grid2
, grid
, area
);
1442 ncoords
= symmetries(params
, x
, y
, coords
, params
->symm
);
1443 for (j
= 0; j
< ncoords
; j
++)
1444 grid2
[coords
[2*j
+1]*cr
+coords
[2*j
]] = 0;
1446 if (nsolve(c
, r
, grid2
) <= maxdiff
) {
1447 for (j
= 0; j
< ncoords
; j
++)
1448 grid
[coords
[2*j
+1]*cr
+coords
[2*j
]] = 0;
1455 * There was nothing we could remove without destroying
1462 memcpy(grid2
, grid
, area
);
1463 } while (nsolve(c
, r
, grid2
) != maxdiff
);
1469 * Now we have the grid as it will be presented to the user.
1470 * Encode it in a game seed.
1476 seed
= snewn(5 * area
, char);
1479 for (i
= 0; i
<= area
; i
++) {
1480 int n
= (i
< area ? grid
[i
] : -1);
1487 int c
= 'a' - 1 + run
;
1491 run
-= c
- ('a' - 1);
1495 * If there's a number in the very top left or
1496 * bottom right, there's no point putting an
1497 * unnecessary _ before or after it.
1499 if (p
> seed
&& n
> 0)
1503 p
+= sprintf(p
, "%d", n
);
1507 assert(p
- seed
< 5 * area
);
1509 seed
= sresize(seed
, p
- seed
, char);
1517 static void game_free_aux_info(game_aux_info
*aux
)
1519 assert(!"Shouldn't happen");
1522 static char *validate_seed(game_params
*params
, char *seed
)
1524 int area
= params
->r
* params
->r
* params
->c
* params
->c
;
1529 if (n
>= 'a' && n
<= 'z') {
1530 squares
+= n
- 'a' + 1;
1531 } else if (n
== '_') {
1533 } else if (n
> '0' && n
<= '9') {
1535 while (*seed
>= '0' && *seed
<= '9')
1538 return "Invalid character in game specification";
1542 return "Not enough data to fill grid";
1545 return "Too much data to fit in grid";
1550 static game_state
*new_game(game_params
*params
, char *seed
)
1552 game_state
*state
= snew(game_state
);
1553 int c
= params
->c
, r
= params
->r
, cr
= c
*r
, area
= cr
* cr
;
1556 state
->c
= params
->c
;
1557 state
->r
= params
->r
;
1559 state
->grid
= snewn(area
, digit
);
1560 state
->immutable
= snewn(area
, unsigned char);
1561 memset(state
->immutable
, FALSE
, area
);
1563 state
->completed
= state
->cheated
= FALSE
;
1568 if (n
>= 'a' && n
<= 'z') {
1569 int run
= n
- 'a' + 1;
1570 assert(i
+ run
<= area
);
1572 state
->grid
[i
++] = 0;
1573 } else if (n
== '_') {
1575 } else if (n
> '0' && n
<= '9') {
1577 state
->immutable
[i
] = TRUE
;
1578 state
->grid
[i
++] = atoi(seed
-1);
1579 while (*seed
>= '0' && *seed
<= '9')
1582 assert(!"We can't get here");
1590 static game_state
*dup_game(game_state
*state
)
1592 game_state
*ret
= snew(game_state
);
1593 int c
= state
->c
, r
= state
->r
, cr
= c
*r
, area
= cr
* cr
;
1598 ret
->grid
= snewn(area
, digit
);
1599 memcpy(ret
->grid
, state
->grid
, area
);
1601 ret
->immutable
= snewn(area
, unsigned char);
1602 memcpy(ret
->immutable
, state
->immutable
, area
);
1604 ret
->completed
= state
->completed
;
1605 ret
->cheated
= state
->cheated
;
1610 static void free_game(game_state
*state
)
1612 sfree(state
->immutable
);
1617 static game_state
*solve_game(game_state
*state
, game_aux_info
*aux
,
1621 int c
= state
->c
, r
= state
->r
;
1625 * I could have stored the grid I invented in the game_aux_info
1626 * and extracted it here where available, but it seems easier
1627 * just to run my internal solver in all cases.
1630 ret
= dup_game(state
);
1631 ret
->completed
= ret
->cheated
= TRUE
;
1633 rsolve_ret
= rsolve(c
, r
, ret
->grid
, NULL
, 2);
1635 if (rsolve_ret
!= 1) {
1637 if (rsolve_ret
== 0)
1638 *error
= "No solution exists for this puzzle";
1640 *error
= "Multiple solutions exist for this puzzle";
1647 static char *grid_text_format(int c
, int r
, digit
*grid
)
1655 * There are cr lines of digits, plus r-1 lines of block
1656 * separators. Each line contains cr digits, cr-1 separating
1657 * spaces, and c-1 two-character block separators. Thus, the
1658 * total length of a line is 2*cr+2*c-3 (not counting the
1659 * newline), and there are cr+r-1 of them.
1661 maxlen
= (cr
+r
-1) * (2*cr
+2*c
-2);
1662 ret
= snewn(maxlen
+1, char);
1665 for (y
= 0; y
< cr
; y
++) {
1666 for (x
= 0; x
< cr
; x
++) {
1667 int ch
= grid
[y
* cr
+ x
];
1677 if ((x
+1) % r
== 0) {
1684 if (y
+1 < cr
&& (y
+1) % c
== 0) {
1685 for (x
= 0; x
< cr
; x
++) {
1689 if ((x
+1) % r
== 0) {
1699 assert(p
- ret
== maxlen
);
1704 static char *game_text_format(game_state
*state
)
1706 return grid_text_format(state
->c
, state
->r
, state
->grid
);
1711 * These are the coordinates of the currently highlighted
1712 * square on the grid, or -1,-1 if there isn't one. When there
1713 * is, pressing a valid number or letter key or Space will
1714 * enter that number or letter in the grid.
1719 static game_ui
*new_ui(game_state
*state
)
1721 game_ui
*ui
= snew(game_ui
);
1723 ui
->hx
= ui
->hy
= -1;
1728 static void free_ui(game_ui
*ui
)
1733 static game_state
*make_move(game_state
*from
, game_ui
*ui
, int x
, int y
,
1736 int c
= from
->c
, r
= from
->r
, cr
= c
*r
;
1740 tx
= (x
+ TILE_SIZE
- BORDER
) / TILE_SIZE
- 1;
1741 ty
= (y
+ TILE_SIZE
- BORDER
) / TILE_SIZE
- 1;
1743 if (tx
>= 0 && tx
< cr
&& ty
>= 0 && ty
< cr
&& button
== LEFT_BUTTON
) {
1744 if (tx
== ui
->hx
&& ty
== ui
->hy
) {
1745 ui
->hx
= ui
->hy
= -1;
1750 return from
; /* UI activity occurred */
1753 if (ui
->hx
!= -1 && ui
->hy
!= -1 &&
1754 ((button
>= '1' && button
<= '9' && button
- '0' <= cr
) ||
1755 (button
>= 'a' && button
<= 'z' && button
- 'a' + 10 <= cr
) ||
1756 (button
>= 'A' && button
<= 'Z' && button
- 'A' + 10 <= cr
) ||
1758 int n
= button
- '0';
1759 if (button
>= 'A' && button
<= 'Z')
1760 n
= button
- 'A' + 10;
1761 if (button
>= 'a' && button
<= 'z')
1762 n
= button
- 'a' + 10;
1766 if (from
->immutable
[ui
->hy
*cr
+ui
->hx
])
1767 return NULL
; /* can't overwrite this square */
1769 ret
= dup_game(from
);
1770 ret
->grid
[ui
->hy
*cr
+ui
->hx
] = n
;
1771 ui
->hx
= ui
->hy
= -1;
1774 * We've made a real change to the grid. Check to see
1775 * if the game has been completed.
1777 if (!ret
->completed
&& check_valid(c
, r
, ret
->grid
)) {
1778 ret
->completed
= TRUE
;
1781 return ret
; /* made a valid move */
1787 /* ----------------------------------------------------------------------
1791 struct game_drawstate
{
1798 #define XSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1799 #define YSIZE(cr) ((cr) * TILE_SIZE + 2*BORDER + 1)
1801 static void game_size(game_params
*params
, int *x
, int *y
)
1803 int c
= params
->c
, r
= params
->r
, cr
= c
*r
;
1809 static float *game_colours(frontend
*fe
, game_state
*state
, int *ncolours
)
1811 float *ret
= snewn(3 * NCOLOURS
, float);
1813 frontend_default_colour(fe
, &ret
[COL_BACKGROUND
* 3]);
1815 ret
[COL_GRID
* 3 + 0] = 0.0F
;
1816 ret
[COL_GRID
* 3 + 1] = 0.0F
;
1817 ret
[COL_GRID
* 3 + 2] = 0.0F
;
1819 ret
[COL_CLUE
* 3 + 0] = 0.0F
;
1820 ret
[COL_CLUE
* 3 + 1] = 0.0F
;
1821 ret
[COL_CLUE
* 3 + 2] = 0.0F
;
1823 ret
[COL_USER
* 3 + 0] = 0.0F
;
1824 ret
[COL_USER
* 3 + 1] = 0.6F
* ret
[COL_BACKGROUND
* 3 + 1];
1825 ret
[COL_USER
* 3 + 2] = 0.0F
;
1827 ret
[COL_HIGHLIGHT
* 3 + 0] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 0];
1828 ret
[COL_HIGHLIGHT
* 3 + 1] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 1];
1829 ret
[COL_HIGHLIGHT
* 3 + 2] = 0.85F
* ret
[COL_BACKGROUND
* 3 + 2];
1831 *ncolours
= NCOLOURS
;
1835 static game_drawstate
*game_new_drawstate(game_state
*state
)
1837 struct game_drawstate
*ds
= snew(struct game_drawstate
);
1838 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1840 ds
->started
= FALSE
;
1844 ds
->grid
= snewn(cr
*cr
, digit
);
1845 memset(ds
->grid
, 0, cr
*cr
);
1846 ds
->hl
= snewn(cr
*cr
, unsigned char);
1847 memset(ds
->hl
, 0, cr
*cr
);
1852 static void game_free_drawstate(game_drawstate
*ds
)
1859 static void draw_number(frontend
*fe
, game_drawstate
*ds
, game_state
*state
,
1860 int x
, int y
, int hl
)
1862 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1867 if (ds
->grid
[y
*cr
+x
] == state
->grid
[y
*cr
+x
] && ds
->hl
[y
*cr
+x
] == hl
)
1868 return; /* no change required */
1870 tx
= BORDER
+ x
* TILE_SIZE
+ 2;
1871 ty
= BORDER
+ y
* TILE_SIZE
+ 2;
1887 clip(fe
, cx
, cy
, cw
, ch
);
1889 /* background needs erasing? */
1890 if (ds
->grid
[y
*cr
+x
] || ds
->hl
[y
*cr
+x
] != hl
)
1891 draw_rect(fe
, cx
, cy
, cw
, ch
, hl ? COL_HIGHLIGHT
: COL_BACKGROUND
);
1893 /* new number needs drawing? */
1894 if (state
->grid
[y
*cr
+x
]) {
1896 str
[0] = state
->grid
[y
*cr
+x
] + '0';
1898 str
[0] += 'a' - ('9'+1);
1899 draw_text(fe
, tx
+ TILE_SIZE
/2, ty
+ TILE_SIZE
/2,
1900 FONT_VARIABLE
, TILE_SIZE
/2, ALIGN_VCENTRE
| ALIGN_HCENTRE
,
1901 state
->immutable
[y
*cr
+x
] ? COL_CLUE
: COL_USER
, str
);
1906 draw_update(fe
, cx
, cy
, cw
, ch
);
1908 ds
->grid
[y
*cr
+x
] = state
->grid
[y
*cr
+x
];
1909 ds
->hl
[y
*cr
+x
] = hl
;
1912 static void game_redraw(frontend
*fe
, game_drawstate
*ds
, game_state
*oldstate
,
1913 game_state
*state
, int dir
, game_ui
*ui
,
1914 float animtime
, float flashtime
)
1916 int c
= state
->c
, r
= state
->r
, cr
= c
*r
;
1921 * The initial contents of the window are not guaranteed
1922 * and can vary with front ends. To be on the safe side,
1923 * all games should start by drawing a big
1924 * background-colour rectangle covering the whole window.
1926 draw_rect(fe
, 0, 0, XSIZE(cr
), YSIZE(cr
), COL_BACKGROUND
);
1931 for (x
= 0; x
<= cr
; x
++) {
1932 int thick
= (x
% r ?
0 : 1);
1933 draw_rect(fe
, BORDER
+ x
*TILE_SIZE
- thick
, BORDER
-1,
1934 1+2*thick
, cr
*TILE_SIZE
+3, COL_GRID
);
1936 for (y
= 0; y
<= cr
; y
++) {
1937 int thick
= (y
% c ?
0 : 1);
1938 draw_rect(fe
, BORDER
-1, BORDER
+ y
*TILE_SIZE
- thick
,
1939 cr
*TILE_SIZE
+3, 1+2*thick
, COL_GRID
);
1944 * Draw any numbers which need redrawing.
1946 for (x
= 0; x
< cr
; x
++) {
1947 for (y
= 0; y
< cr
; y
++) {
1948 draw_number(fe
, ds
, state
, x
, y
,
1949 (x
== ui
->hx
&& y
== ui
->hy
) ||
1951 (flashtime
<= FLASH_TIME
/3 ||
1952 flashtime
>= FLASH_TIME
*2/3)));
1957 * Update the _entire_ grid if necessary.
1960 draw_update(fe
, 0, 0, XSIZE(cr
), YSIZE(cr
));
1965 static float game_anim_length(game_state
*oldstate
, game_state
*newstate
,
1971 static float game_flash_length(game_state
*oldstate
, game_state
*newstate
,
1974 if (!oldstate
->completed
&& newstate
->completed
&&
1975 !oldstate
->cheated
&& !newstate
->cheated
)
1980 static int game_wants_statusbar(void)
1986 #define thegame solo
1989 const struct game thegame
= {
1990 "Solo", "games.solo",
1997 TRUE
, game_configure
, custom_params
,
2006 TRUE
, game_text_format
,
2013 game_free_drawstate
,
2017 game_wants_statusbar
,
2020 #ifdef STANDALONE_SOLVER
2023 * gcc -DSTANDALONE_SOLVER -o solosolver solo.c malloc.c
2026 void frontend_default_colour(frontend
*fe
, float *output
) {}
2027 void draw_text(frontend
*fe
, int x
, int y
, int fonttype
, int fontsize
,
2028 int align
, int colour
, char *text
) {}
2029 void draw_rect(frontend
*fe
, int x
, int y
, int w
, int h
, int colour
) {}
2030 void draw_line(frontend
*fe
, int x1
, int y1
, int x2
, int y2
, int colour
) {}
2031 void draw_polygon(frontend
*fe
, int *coords
, int npoints
,
2032 int fill
, int colour
) {}
2033 void clip(frontend
*fe
, int x
, int y
, int w
, int h
) {}
2034 void unclip(frontend
*fe
) {}
2035 void start_draw(frontend
*fe
) {}
2036 void draw_update(frontend
*fe
, int x
, int y
, int w
, int h
) {}
2037 void end_draw(frontend
*fe
) {}
2038 unsigned long random_bits(random_state
*state
, int bits
)
2039 { assert(!"Shouldn't get randomness"); return 0; }
2040 unsigned long random_upto(random_state
*state
, unsigned long limit
)
2041 { assert(!"Shouldn't get randomness"); return 0; }
2043 void fatal(char *fmt
, ...)
2047 fprintf(stderr
, "fatal error: ");
2050 vfprintf(stderr
, fmt
, ap
);
2053 fprintf(stderr
, "\n");
2057 int main(int argc
, char **argv
)
2062 char *id
= NULL
, *seed
, *err
;
2066 while (--argc
> 0) {
2068 if (!strcmp(p
, "-r")) {
2070 } else if (!strcmp(p
, "-n")) {
2072 } else if (!strcmp(p
, "-v")) {
2073 solver_show_working
= TRUE
;
2075 } else if (!strcmp(p
, "-g")) {
2078 } else if (*p
== '-') {
2079 fprintf(stderr
, "%s: unrecognised option `%s'\n", argv
[0]);
2087 fprintf(stderr
, "usage: %s [-n | -r | -g | -v] <game_id>\n", argv
[0]);
2091 seed
= strchr(id
, ':');
2093 fprintf(stderr
, "%s: game id expects a colon in it\n", argv
[0]);
2098 p
= decode_params(id
);
2099 err
= validate_seed(p
, seed
);
2101 fprintf(stderr
, "%s: %s\n", argv
[0], err
);
2104 s
= new_game(p
, seed
);
2107 int ret
= rsolve(p
->c
, p
->r
, s
->grid
, NULL
, 2);
2109 fprintf(stderr
, "%s: rsolve: multiple solutions detected\n",
2113 int ret
= nsolve(p
->c
, p
->r
, s
->grid
);
2115 if (ret
== DIFF_IMPOSSIBLE
) {
2117 * Now resort to rsolve to determine whether it's
2120 ret
= rsolve(p
->c
, p
->r
, s
->grid
, NULL
, 2);
2122 ret
= DIFF_IMPOSSIBLE
;
2124 ret
= DIFF_RECURSIVE
;
2126 ret
= DIFF_AMBIGUOUS
;
2128 printf("Difficulty rating: %s\n",
2129 ret
==DIFF_BLOCK ?
"Trivial (blockwise positional elimination only)":
2130 ret
==DIFF_SIMPLE ?
"Basic (row/column/number elimination required)":
2131 ret
==DIFF_INTERSECT ?
"Intermediate (intersectional analysis required)":
2132 ret
==DIFF_SET ?
"Advanced (set elimination required)":
2133 ret
==DIFF_RECURSIVE ?
"Unreasonable (guesswork and backtracking required)":
2134 ret
==DIFF_AMBIGUOUS ?
"Ambiguous (multiple solutions exist)":
2135 ret
==DIFF_IMPOSSIBLE ?
"Impossible (no solution exists)":
2136 "INTERNAL ERROR: unrecognised difficulty code");
2140 printf("%s\n", grid_text_format(p
->c
, p
->r
, s
->grid
));