Pearl: re-use a single grid structure when generating

Pearl generally has to generate quite a lot of candidate loops before
it can find one that makes a viable puzzle.  Before this change it
generated a new grid structure for each of those candidate loops.  The
result was that grid_new() accounted for over 5% of the
puzzle-generation time.

Pulling grid_new() out of the loop-generation loop makes "pearl
--generate 100 8x8dt#0" about 6% faster on my laptop, while producing
precisely the same output.  Most of this change is just renaming the
"grid" variable in new_clues() so it doesn't collide with the typedef
of the same name.

0 files changed, 0 insertions, 0 deletions