6 typedef unsigned char digit
;
8 /* --- Solver structures, definitions --- */
10 #ifdef STANDALONE_SOLVER
11 int solver_show_working
, solver_recurse_depth
;
15 int o
; /* order of latin square */
16 unsigned char *cube
; /* o^3, indexed by x, y, and digit:
17 TRUE in that position indicates a possibility */
18 digit
*grid
; /* o^2, indexed by x and y: for final deductions */
20 unsigned char *row
; /* o^2: row[y*cr+n-1] TRUE if n is in row y */
21 unsigned char *col
; /* o^2: col[x*cr+n-1] TRUE if n is in col x */
23 #define cubepos(x,y,n) (((x)*solver->o+(y))*solver->o+(n)-1)
24 #define cube(x,y,n) (solver->cube[cubepos(x,y,n)])
26 #define gridpos(x,y) ((y)*solver->o+(x))
27 #define grid(x,y) (solver->grid[gridpos(x,y)])
29 /* A solo solver using this code would need these defined. See solo.c. */
34 #define YUNTRANS(y) (y)
38 /* --- Solver individual strategies --- */
40 /* Place a value at a specific location. */
41 void latin_solver_place(struct latin_solver
*solver
, int x
, int y
, int n
);
43 /* Positional elimination. */
44 int latin_solver_elim(struct latin_solver
*solver
, int start
, int step
45 #ifdef STANDALONE_SOLVER
50 struct latin_solver_scratch
; /* private to latin.c */
52 int latin_solver_set(struct latin_solver
*solver
,
53 struct latin_solver_scratch
*scratch
,
54 int start
, int step1
, int step2
55 #ifdef STANDALONE_SOLVER
61 int latin_solver_forcing(struct latin_solver
*solver
,
62 struct latin_solver_scratch
*scratch
);
65 /* --- Solver allocation --- */
67 /* Fills in (and allocates members for) a latin_solver struct.
68 * Will allocate members of snew, but not snew itself
69 * (allowing 'struct latin_solver' to be the first element in a larger
70 * struct, for example). */
71 void latin_solver_alloc(struct latin_solver
*solver
, digit
*grid
, int o
);
72 void latin_solver_free(struct latin_solver
*solver
);
74 /* Allocates scratch space (for _set and _forcing) */
75 struct latin_solver_scratch
*
76 latin_solver_new_scratch(struct latin_solver
*solver
);
77 void latin_solver_free_scratch(struct latin_solver_scratch
*scratch
);
80 /* --- Solver guts --- */
82 /* Looped positional elimination */
83 int latin_solver_diff_simple(struct latin_solver
*solver
);
85 /* Looped set elimination; *extreme is set if it used
86 * the more difficult single-number elimination. */
87 int latin_solver_diff_set(struct latin_solver
*solver
,
88 struct latin_solver_scratch
*scratch
,
91 typedef int (latin_solver_callback
)(digit
*, int, int, void*);
92 /* Use to provide a standard way of dealing with solvers which can recurse;
93 * pass in your enumeration for 'recursive diff' and your solver
94 * callback. Returns #solutions (0 == already solved). */
95 int latin_solver_recurse(struct latin_solver
*solver
, int recdiff
,
96 latin_solver_callback cb
, void *ctx
);
98 /* Individual puzzles should use their enumerations for their
99 * own difficulty levels, ensuring they don't clash with these. */
100 enum { diff_impossible
= 10, diff_ambiguous
, diff_unfinished
};
101 int latin_solver(digit
*grid
, int order
, int maxdiff
, void *unused
);
103 void latin_solver_debug(unsigned char *cube
, int o
);
105 /* --- Generation and checking --- */
107 digit
*latin_generate_quick(int o
, random_state
*rs
);
108 digit
*latin_generate(int o
, random_state
*rs
);
110 int latin_check(digit
*sq
, int order
); /* !0 => not a latin square */
112 void latin_debug(digit
*sq
, int order
);