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Files
115 lines
3.7 KiB
C
115 lines
3.7 KiB
C
#ifndef LATIN_H
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#define LATIN_H
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#include "puzzles.h"
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typedef unsigned char digit;
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/* --- Solver structures, definitions --- */
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#ifdef STANDALONE_SOLVER
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int solver_show_working, solver_recurse_depth;
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#endif
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struct latin_solver {
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int o; /* order of latin square */
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unsigned char *cube; /* o^3, indexed by x, y, and digit:
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TRUE in that position indicates a possibility */
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digit *grid; /* o^2, indexed by x and y: for final deductions */
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unsigned char *row; /* o^2: row[y*cr+n-1] TRUE if n is in row y */
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unsigned char *col; /* o^2: col[x*cr+n-1] TRUE if n is in col x */
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};
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#define cubepos(x,y,n) (((x)*solver->o+(y))*solver->o+(n)-1)
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#define cube(x,y,n) (solver->cube[cubepos(x,y,n)])
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#define gridpos(x,y) ((y)*solver->o+(x))
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#define grid(x,y) (solver->grid[gridpos(x,y)])
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/* A solo solver using this code would need these defined. See solo.c. */
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#ifndef YTRANS
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#define YTRANS(y) (y)
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#endif
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#ifndef YUNTRANS
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#define YUNTRANS(y) (y)
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#endif
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/* --- Solver individual strategies --- */
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/* Place a value at a specific location. */
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void latin_solver_place(struct latin_solver *solver, int x, int y, int n);
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/* Positional elimination. */
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int latin_solver_elim(struct latin_solver *solver, int start, int step
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#ifdef STANDALONE_SOLVER
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, char *fmt, ...
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#endif
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);
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struct latin_solver_scratch; /* private to latin.c */
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/* Set elimination */
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int latin_solver_set(struct latin_solver *solver,
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struct latin_solver_scratch *scratch,
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int start, int step1, int step2
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#ifdef STANDALONE_SOLVER
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, char *fmt, ...
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#endif
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);
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/* Forcing chains */
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int latin_solver_forcing(struct latin_solver *solver,
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struct latin_solver_scratch *scratch);
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/* --- Solver allocation --- */
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/* Fills in (and allocates members for) a latin_solver struct.
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* Will allocate members of snew, but not snew itself
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* (allowing 'struct latin_solver' to be the first element in a larger
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* struct, for example). */
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void latin_solver_alloc(struct latin_solver *solver, digit *grid, int o);
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void latin_solver_free(struct latin_solver *solver);
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/* Allocates scratch space (for _set and _forcing) */
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struct latin_solver_scratch *
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latin_solver_new_scratch(struct latin_solver *solver);
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void latin_solver_free_scratch(struct latin_solver_scratch *scratch);
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/* --- Solver guts --- */
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/* Looped positional elimination */
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int latin_solver_diff_simple(struct latin_solver *solver);
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/* Looped set elimination; *extreme is set if it used
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* the more difficult single-number elimination. */
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int latin_solver_diff_set(struct latin_solver *solver,
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struct latin_solver_scratch *scratch,
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int extreme);
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typedef int (latin_solver_callback)(digit *, int, int, void*);
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/* Use to provide a standard way of dealing with solvers which can recurse;
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* pass in your enumeration for 'recursive diff' and your solver
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* callback. Returns #solutions (0 == already solved). */
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int latin_solver_recurse(struct latin_solver *solver, int recdiff,
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latin_solver_callback cb, void *ctx);
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/* Individual puzzles should use their enumerations for their
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* own difficulty levels, ensuring they don't clash with these. */
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enum { diff_impossible = 10, diff_ambiguous, diff_unfinished };
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int latin_solver(digit *grid, int order, int maxdiff, void *unused);
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void latin_solver_debug(unsigned char *cube, int o);
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/* --- Generation and checking --- */
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digit *latin_generate_quick(int o, random_state *rs);
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digit *latin_generate(int o, random_state *rs);
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int latin_check(digit *sq, int order); /* !0 => not a latin square */
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void latin_debug(digit *sq, int order);
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#endif
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