ref: a33d9fad02d6319cb9061119a6165ed5493a3ba5
dir: /latin.h/
#ifndef LATIN_H #define LATIN_H #include "puzzles.h" typedef unsigned char digit; /* --- Solver structures, definitions --- */ #ifdef STANDALONE_SOLVER extern int solver_show_working, solver_recurse_depth; #endif struct latin_solver { int o; /* order of latin square */ unsigned char *cube; /* o^3, indexed by x, y, and digit: true in that position indicates a possibility */ digit *grid; /* o^2, indexed by x and y: for final deductions */ unsigned char *row; /* o^2: row[y*cr+n-1] true if n is in row y */ unsigned char *col; /* o^2: col[x*cr+n-1] true if n is in col x */ #ifdef STANDALONE_SOLVER char **names; /* o: names[n-1] gives name of 'digit' n */ #endif }; #define cubepos(x,y,n) (((x)*solver->o+(y))*solver->o+(n)-1) #define cube(x,y,n) (solver->cube[cubepos(x,y,n)]) #define gridpos(x,y) ((y)*solver->o+(x)) #define grid(x,y) (solver->grid[gridpos(x,y)]) /* --- Solver individual strategies --- */ /* Place a value at a specific location. */ void latin_solver_place(struct latin_solver *solver, int x, int y, int n); /* Positional elimination. */ int latin_solver_elim(struct latin_solver *solver, int start, int step #ifdef STANDALONE_SOLVER , const char *fmt, ... #endif ); struct latin_solver_scratch; /* private to latin.c */ /* Set elimination */ int latin_solver_set(struct latin_solver *solver, struct latin_solver_scratch *scratch, int start, int step1, int step2 #ifdef STANDALONE_SOLVER , const char *fmt, ... #endif ); /* Forcing chains */ int latin_solver_forcing(struct latin_solver *solver, struct latin_solver_scratch *scratch); /* --- Solver allocation --- */ /* Fills in (and allocates members for) a latin_solver struct. * Will allocate members of solver, but not solver itself * (allowing 'struct latin_solver' to be the first element in a larger * struct, for example). * * latin_solver_alloc returns false if the digits already in the grid * could not be legally placed. */ bool latin_solver_alloc(struct latin_solver *solver, digit *grid, int o); void latin_solver_free(struct latin_solver *solver); /* Allocates scratch space (for _set and _forcing) */ struct latin_solver_scratch * latin_solver_new_scratch(struct latin_solver *solver); void latin_solver_free_scratch(struct latin_solver_scratch *scratch); /* --- Solver guts --- */ /* Looped positional elimination */ int latin_solver_diff_simple(struct latin_solver *solver); /* Looped set elimination; extreme permits use of the more difficult * single-number elimination. */ int latin_solver_diff_set(struct latin_solver *solver, struct latin_solver_scratch *scratch, bool extreme); typedef int (*usersolver_t)(struct latin_solver *solver, void *ctx); typedef bool (*validator_t)(struct latin_solver *solver, void *ctx); typedef void *(*ctxnew_t)(void *ctx); typedef void (*ctxfree_t)(void *ctx); /* Individual puzzles should use their enumerations for their * own difficulty levels, ensuring they don't clash with these. */ enum { diff_impossible = 10, diff_ambiguous, diff_unfinished }; /* Externally callable function that allocates and frees a latin_solver */ int latin_solver(digit *grid, int o, int maxdiff, int diff_simple, int diff_set_0, int diff_set_1, int diff_forcing, int diff_recursive, usersolver_t const *usersolvers, validator_t valid, void *ctx, ctxnew_t ctxnew, ctxfree_t ctxfree); /* Version you can call if you want to alloc and free latin_solver yourself */ int latin_solver_main(struct latin_solver *solver, int maxdiff, int diff_simple, int diff_set_0, int diff_set_1, int diff_forcing, int diff_recursive, usersolver_t const *usersolvers, validator_t valid, void *ctx, ctxnew_t ctxnew, ctxfree_t ctxfree); void latin_solver_debug(unsigned char *cube, int o); /* --- Generation and checking --- */ digit *latin_generate(int o, random_state *rs); /* The order of the latin rectangle is max(w,h). */ digit *latin_generate_rect(int w, int h, random_state *rs); bool latin_check(digit *sq, int order); /* true => not a latin square */ void latin_debug(digit *sq, int order); #endif