Add a difficulty exception to prevent Pearl spinning forever when

asked to generate a 5x5 Tricky puzzle. (Debian bug #667963)

[originally from svn r9454]
This commit is contained in:
Simon Tatham
2012-04-08 13:45:10 +00:00
parent b40b89f879
commit ec732a4f4e

18
pearl.c
View File

@ -1161,9 +1161,17 @@ void pearl_loopgen(int w, int h, char *lines, random_state *rs)
static int new_clues(game_params *params, random_state *rs,
char *clues, char *grid)
{
int w = params->w, h = params->h;
int w = params->w, h = params->h, diff = params->difficulty;
int ngen = 0, x, y, d, ret, i;
/*
* Difficulty exception: 5x5 Tricky is not generable (the
* generator will spin forever trying) and so we fudge it to Easy.
*/
if (w == 5 && h == 5 && diff > DIFF_EASY)
diff = DIFF_EASY;
while (1) {
ngen++;
pearl_loopgen(w, h, grid, rs);
@ -1245,7 +1253,7 @@ static int new_clues(game_params *params, random_state *rs,
/*
* See if we can solve the puzzle just like this.
*/
ret = pearl_solve(w, h, clues, grid, params->difficulty, FALSE);
ret = pearl_solve(w, h, clues, grid, diff, FALSE);
assert(ret > 0); /* shouldn't be inconsistent! */
if (ret != 1)
continue; /* go round and try again */
@ -1253,8 +1261,8 @@ static int new_clues(game_params *params, random_state *rs,
/*
* Check this puzzle isn't too easy.
*/
if (params->difficulty > DIFF_EASY) {
ret = pearl_solve(w, h, clues, grid, params->difficulty-1, FALSE);
if (diff > DIFF_EASY) {
ret = pearl_solve(w, h, clues, grid, diff-1, FALSE);
assert(ret > 0);
if (ret == 1)
continue; /* too easy: try again */
@ -1321,7 +1329,7 @@ static int new_clues(game_params *params, random_state *rs,
clue = clues[y*w+x];
clues[y*w+x] = 0; /* try removing this clue */
ret = pearl_solve(w, h, clues, grid, params->difficulty, FALSE);
ret = pearl_solve(w, h, clues, grid, diff, FALSE);
assert(ret > 0);
if (ret != 1)
clues[y*w+x] = clue; /* oops, put it back again */