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hyperrogue/rogueviz/dhrg/regular.cpp
2022-07-12 14:46:31 +02:00

114 lines
3.5 KiB
C++

// find the value of D(G) algorithmically (see the paper)
namespace dhrg {
// c2-c1
int cycle_minus(cell *c2, cell *c1) {
int acc = 0;
while(c1 != c2) c1 = ts::right_of(c1, celldist), acc++;
return acc;
}
// c2 to the right from c1
int unlimited_distance(cell *c2, cell *c1) {
int at_least = cycle_minus(c2, c1);
int steps = 0;
while(true) {
steps += 2;
if(steps >= at_least) return at_least;
c1 = ts::right_parent(c1, celldist);
c2 = ts::left_parent(c2, celldist);
int ndist = steps + cycle_minus(c2, c1);
if(ndist < at_least) at_least = ndist;
}
}
int gettypeof(cell *c) { return type_in_reduced(*(cgi.expansion), c, celldist); }
vector<bool> grow_forever;
set<vector<int>> checked;
bool err = false;
int my_sibling_limit;
void find_sibling_limit(cell *c2, cell *c1) {
if(err) return;
if(celldist(c2) != celldist(c1)) {
printf("not the same ring %d/%d\n", celldist(c1), celldist(c2));
c1->item = itSilver;
c2->item = itGold;
err = true;
return;
}
vector<int> signature;
cell *cx = c1;
cell *cy = c1;
bool gf = false;
while(cx != c2) {
int t = gettypeof(cx);
if(cx != c1 && grow_forever[t]) gf = true;
signature.push_back(t); cy = cx; cx = ts::right_of(cx, celldist);
}
signature.push_back(gettypeof(cx)); signature.push_back(unlimited_distance(cy, c1) - unlimited_distance(c2, c1));
if(checked.count(signature)) return;
checked.insert(signature);
// for(int v: signature) printf("%d ", v);
int cm = cycle_minus(c2, c1);
int ud = c1 == c2 ? -1 : 2 + unlimited_distance(ts::left_parent(c2, celldist), ts::right_parent(c1, celldist));
// printf(": %d/%d {%p/%p} [%d]\n", cm, ud, c1, c2, my_sibling_limit);
if(cm < ud && cm > my_sibling_limit) { my_sibling_limit = cm; }
if(gf) return;
int t1 = gettypeof(c1);
int t2 = gettypeof(c2);
for(int i1=0; i1<isize(cgi.expansion->children[t1]); i1++)
for(int i2=0; i2<isize(cgi.expansion->children[t2]); i2++)
if(c1 != c2 || i1 <= i2+1)
find_sibling_limit(ts::child_number(c2, i2+1, celldist), ts::child_number(c1, i1, celldist));
}
void correct_sibling_limit() {
my_sibling_limit = 0;
if(S3 < 4) {
grow_forever.clear();
grow_forever.resize(cgi.expansion->N, true);
while(true) {
bool changed = false;
for(int i=0; i<cgi.expansion->N; i++) if(grow_forever[i]) {
grow_forever[i] = false;
if(isize(cgi.expansion->children[i]) == 0)
throw hr_exception("Error: our algorithm does not work if some vertices have no tree children");
if(isize(cgi.expansion->children[i]) > 1)
for(int c: cgi.expansion->children[i])
if(grow_forever[c] || c == i) grow_forever[i] = true;
if(!grow_forever[i]) changed = true;
}
if(!changed) break;
}
print(hlog, "The following grow forever:"); for(int i=0; i<cgi.expansion->N; i++) if(grow_forever[i]) print(hlog, " ", i); println(hlog);
cell *root = currentmap->gamestart();
my_sibling_limit = 0;
forCellCM(c1, root) forCellCM(c2, root) find_sibling_limit(c2, c1);
}
println(hlog, "The correct value of sibling_limit is ", my_sibling_limit);
cgi.expansion->sibling_limit = my_sibling_limit;
}
void regular_info() {
indenter_finish im("regular_info");
cgi.expansion->get_descendants(0);
println(hlog, "growth = ", cgi.expansion->get_growth());
// int typecount = expansion.N;
correct_sibling_limit();
}
}