removeEdge method

Implementation

@override
void removeEdge(Node parent, Node child) {
  if (!containsNode(parent.key)) {
    throw StateError('Node "${parent.key}" does not exist in graph (parent)');
  }
  if (!containsNode(child.key)) {
    throw StateError('Node "${child.key}" does not exist in graph (child)');
  }

  if (!_edges.containsKey(parent) || !_edges[parent]!.contains(child)) {
    throw StateError('Edge between "${parent.key}" and "${child.key}" does not exist');
  }

  _parents.remove(child);
  final childSet = _edges[parent]!;
  childSet.remove(child);
  if (childSet.isEmpty) {
    _edges[parent] = <Node>{}; // Оставляем пустой сет вместо удаления
  }
  _invalidateCache();
}