//! Get the label for the entity identified by the given numeric id.
//! The InvalidId exception is thrown if there is no matching entity in the database.
//! @return entity label.
const std::string&
resolve(unsigned int id)
{
Concurrency::ScopedMutex l(m_lock);
EntitiesById::iterator itr = m_by_id.find(id);
if (itr == m_by_id.end())
throw InvalidId(id);
return itr->second->label;
}
UnionFind::IdType UnionFind::getRoot(IdType current)
{
if (current >= m_fathers.size())
throw InvalidId(current);
std::vector<IdType> path;
auto root = current;
for (; root != m_fathers[root]; root = m_fathers[root])
path.push_back(root);
for (auto i : path)
m_fathers[i] = root;
++(m_weights[root]);
return root;
}