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Galaxies: fix recursion depth limit in solver.

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The static variable 'solver_recurse_depth' is _mostly_ used by the
standalone solver, to appropriately indent the solver diagnostics for
the current recursion level. So most uses of it are guarded by an
'#ifdef STANDALONE_SOLVER' statement, or some equivalent (such as
being inside the solvep() macro).

One exception is the check that limits the recursion depth to 5, to
avoid getting hung up forever on a too-hard game. Unfortunately, this
check depends on the variable actually incrementing when we recurse
another level - and it wasn't, because the increment itself was under
ifdef! So the generator in live Galaxies could recurse arbitrarily
deep, and generate puzzles that the standalone solver found too hard
_even_ at Unreasonable mode.

Removed the ifdefs, so that solver_recurse_depth is now incremented
and decremented. Also, make sure to initialise the depth to 0 at the
start of a solver run, just in case it had a bogus value left over
from a previous run.
This commit is contained in:
Simon Tatham
2023-03-12 14:11:34 +00:00
parent 08009f3949
commit f018ef97d3
1 changed files with 9 additions and 6 deletions
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15
galaxies.c
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@ -187,6 +187,7 @@ struct game_state {
};
static bool check_complete(const game_state *state, int *dsf, int *colours);
static int solver_state_inner(game_state *state, int maxdiff);
static int solver_state(game_state *state, int maxdiff);
static int solver_obvious(game_state *state);
static int solver_obvious_dot(game_state *state, space *dot);
@ -2415,9 +2416,7 @@ static int solver_recurse(game_state *state, int maxdiff)
solver_recurse_depth*4, "",
rctx.best->x, rctx.best->y, rctx.bestn));
#ifdef STANDALONE_SOLVER
solver_recurse_depth++;
#endif
ingrid = snewn(gsz, space);
memcpy(ingrid, state->grid, gsz * sizeof(space));
@ -2432,7 +2431,7 @@ static int solver_recurse(game_state *state, int maxdiff)
state->dots[n]->x, state->dots[n]->y,
"Attempting for recursion");
ret = solver_state(state, maxdiff);
ret = solver_state_inner(state, maxdiff);
if (diff == DIFF_IMPOSSIBLE && ret != DIFF_IMPOSSIBLE) {
/* we found our first solved grid; copy it away. */
@ -2464,9 +2463,7 @@ static int solver_recurse(game_state *state, int maxdiff)
break;
}
#ifdef STANDALONE_SOLVER
solver_recurse_depth--;
#endif
if (outgrid) {
/* we found (at least one) soln; copy it back to state */
@ -2477,7 +2474,7 @@ static int solver_recurse(game_state *state, int maxdiff)
return diff;
}
static int solver_state(game_state *state, int maxdiff)
static int solver_state_inner(game_state *state, int maxdiff)
{
solver_ctx *sctx = new_solver(state);
int ret, diff = DIFF_NORMAL;
@ -2544,6 +2541,12 @@ got_result:
return diff;
}
static int solver_state(game_state *state, int maxdiff)
{
solver_recurse_depth = 0;
return solver_state_inner(state, maxdiff);
}
#ifndef EDITOR
static char *solve_game(const game_state *state, const game_state *currstate,
const char *aux, const char **error)