Greatly increase the speed of the Filling solver.

This commit is contained in:
Jonas Kölker
2015-10-01 19:57:49 +02:00
committed by Simon Tatham
parent 79fe68dc57
commit a55607ff24

View File

@ -395,25 +395,10 @@ static void make_board(int *board, int w, int h, random_state *rs) {
assert(FALSE); /* unreachable */
}
static int rhofree(int *hop, int start) {
int turtle = start, rabbit = hop[start];
while (rabbit != turtle) { /* find a cycle */
turtle = hop[turtle];
rabbit = hop[hop[rabbit]];
}
do { /* check that start is in the cycle */
rabbit = hop[rabbit];
if (start == rabbit) return 1;
} while (rabbit != turtle);
return 0;
}
static void merge(int *dsf, int *connected, int a, int b) {
int c;
assert(dsf);
assert(connected);
assert(rhofree(connected, a));
assert(rhofree(connected, b));
a = dsf_canonify(dsf, a);
b = dsf_canonify(dsf, b);
if (a == b) return;
@ -421,8 +406,6 @@ static void merge(int *dsf, int *connected, int a, int b) {
c = connected[a];
connected[a] = connected[b];
connected[b] = c;
assert(rhofree(connected, a));
assert(rhofree(connected, b));
}
static void *memdup(const void *ptr, size_t len, size_t esz) {
@ -613,6 +596,7 @@ static int learn_expand_or_one(struct solver_state *s, int w, int h) {
(s->board[idx] >= expandsize(s->board, s->dsf, w, h,
i, s->board[idx]))))
one = FALSE;
if (dsf_size(s->dsf, idx) == s->board[idx]) continue;
assert(s->board[i] == EMPTY);
s->board[i] = -SENTINEL;
if (check_capacity(s->board, w, h, idx)) continue;
@ -735,14 +719,24 @@ static int learn_critical_square(struct solver_state *s, int w, int h) {
/* for each connected component */
for (i = 0; i < sz; ++i) {
int j;
int j, slack;
if (s->board[i] == EMPTY) continue;
if (i != dsf_canonify(s->dsf, i)) continue;
if (dsf_size(s->dsf, i) == s->board[i]) continue;
slack = s->board[i] - dsf_size(s->dsf, i);
if (slack == 0) continue;
assert(s->board[i] != 1);
/* for each empty square */
for (j = 0; j < sz; ++j) {
if (s->board[j] != EMPTY) continue;
if (s->board[j] == EMPTY) {
/* if it's too far away from the CC, don't bother */
int k = i, jx = j % w, jy = j / w;
do {
int kx = k % w, ky = k / w;
if (abs(kx - jx) + abs(ky - jy) <= slack) break;
k = s->connected[k];
} while (i != k);
if (i == k) continue; /* not within range */
} else continue;
s->board[j] = -SENTINEL;
if (check_capacity(s->board, w, h, i)) continue;
/* if not expanding s->board[i] to s->board[j] implies