Nested<const int> SegmentSoup::neighbors() const {
if (nodes() && !neighbors_.size()) {
Array<int> lengths(nodes());
for(int s=0;s<elements.size();s++)
for(int a=0;a<2;a++)
lengths[elements[s][a]]++;
neighbors_ = Nested<int>(lengths);
for(int s=0;s<elements.size();s++) {
int i,j;elements[s].get(i,j);
neighbors_(i,neighbors_.size(i)-lengths[i]--) = j;
neighbors_(j,neighbors_.size(j)-lengths[j]--) = i;
}
// Sort and remove duplicates if necessary
bool need_copy = false;
for(int i=0;i<nodes();i++) {
RawArray<int> n = neighbors_[i];
sort(n);
int* last = std::unique(n.begin(),n.end());
if(last!=n.end())
need_copy = true;
lengths[i] = int(last-n.begin());
}
if (need_copy) {
Nested<int> copy(lengths);
for(int i=0;i<nodes();i++)
copy[i] = neighbors_[i].slice(0,lengths[i]);
neighbors_ = copy;
}
}
return neighbors_;
}
