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typedef struct {
cube_t cube;
uint8_t depth;
int64_t maxsols;
char **nextsol;
int64_t *nsols;
uint8_t nmoves;
uint8_t moves[20];
uint8_t (*estimate)(cube_t);
} dfsarg_generic_t;
_static void solve_generic_appendsolution(dfsarg_generic_t *);
_static int solve_generic_dfs(dfsarg_generic_t *);
_static int64_t solve_generic(cube_t, const char *, int8_t, int8_t, int64_t,
int8_t, char *, uint8_t (*)(cube_t));
_static uint8_t estimate_simple(cube_t);
_static int64_t solve_simple(cube_t, int8_t, int8_t, int64_t, int8_t, char *);
_static void
solve_generic_appendsolution(dfsarg_generic_t *arg)
{
int strl;
strl = writemoves(arg->moves, arg->nmoves, *arg->nextsol);
LOG("Solution found: %s\n", *arg->nextsol);
*arg->nextsol += strl;
**arg->nextsol = '\n';
(*arg->nextsol)++;
(*arg->nsols)++;
}
_static int
solve_generic_dfs(dfsarg_generic_t *arg)
{
dfsarg_generic_t nextarg;
uint8_t m, bound;
int64_t ret;
if (!allowednextmove(arg->moves, arg->nmoves))
return 0;
if (arg->nmoves > 0)
arg->cube = move(arg->cube, arg->moves[arg->nmoves-1]);
bound = arg->estimate(arg->cube);
if (*arg->nsols == arg->maxsols || bound + arg->nmoves > arg->depth)
return 0;
if (bound == 0) {
if (arg->nmoves != arg->depth)
return 0;
solve_generic_appendsolution(arg);
return 1;
}
nextarg = *arg;
nextarg.nmoves = arg->nmoves + 1;
for (m = 0, ret = 0; m < 18; m++) {
nextarg.cube = arg->cube;
nextarg.moves[arg->nmoves] = m;
ret += solve_generic_dfs(&nextarg);
}
return ret;
}
_static int64_t
solve_generic(
cube_t cube,
const char *nisstype,
/* TODO: handle NISS */
int8_t minmoves,
int8_t maxmoves,
int64_t maxsols,
int8_t optimal,
char *sols,
uint8_t (*estimate)(cube_t)
/* TODO: add validator */
/* TODO: maybe add data for estimate */
/* TODO: add moveset (and allowednext?) */
)
{
dfsarg_generic_t arg;
int64_t ret, tmp, first;
if (issolved(cube)) {
LOG("solve: cube is already solved\n");
sols[0] = '\n';
sols[1] = 0;
return 1;
}
if (estimate == NULL) {
LOG("solve: 'estimate' is NULL\n");
return -1;
}
arg = (dfsarg_generic_t) {
.cube = cube,
.maxsols = maxsols,
.nextsol = &sols,
.nsols = &ret,
.nmoves = 0,
.moves = {0},
.estimate = estimate,
};
ret = 0;
first = -1;
for (arg.depth = minmoves; arg.depth <= maxmoves; arg.depth++) {
tmp = solve_generic_dfs(&arg);
if (tmp != 0)
first = arg.depth;
LOG("Found %" PRId64 " solution%s at depth %" PRIu8 "\n",
tmp, tmp == 1 ? "" : "s", arg.depth);
if (ret >= maxsols)
break;
if (optimal >= 0 && first >= 0 && arg.depth - first == optimal)
break;
}
DBG_ASSERT(ret <= maxsols, ret,
"solve: found more than 'maxsols' solutions\n");
return ret;
}
_static uint8_t
estimate_simple(cube_t cube)
{
return issolved(cube) ? 0 : 1;
}
_static int64_t
solve_simple(
cube_t cube,
int8_t minmoves,
int8_t maxmoves,
int64_t maxsols,
int8_t optimal,
char *solutions
)
{
return solve_generic(
cube,
"",
minmoves,
maxmoves,
maxsols,
optimal,
solutions,
&estimate_simple
);
}
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