l" << endl; #endif                                                      }                                                  // Fill in deepest_child_edge for the parent if not filled in already, or if we beat what's there.                         // Also maintain parent's second_deepest_child_edge.                         auto parent_deepest_child_it = deepest_child_edge.find(parent_head);                         if (parent_deepest_child_it == deepest_child_edge.end()) {                          #ifdef debug                             cerr << "\t\tWe are our parent's deepest child by default!" << endl; #endif                                                      // Emplace in the map where we didn't find anything.                             deepest_child_edge.emplace_hint(parent_deepest_child_it, parent_head, 