Replace:
nie można najpierw usuwać a potem dodawać , bo w międzyczasie zmieniłoby
się drzewo. Trzeba sklonować, potem usunąć i wstawić.
void InsertOneChild(int index, shared_ptr<Node> node)
{
childs.insert(childs.begin() + index, node);
node->parent = this;
}

void ReplaceChild(int index, shared_ptr<Node> subtree)
{
shared_ptr<Node> clone = subtree->cloneTree();
deleteChild(index);
InsertOneChild(index, clone);
clone->setLevel(level + 1);
}


int main()
{
shared_ptr<Node>root,rootB;
root = make_shared<Node>("1");
root->AddTree(make_shared<Node>("2"));
root->AddTree(make_shared<Node>("3"));
root->at(0)->AddTree(make_shared<Node>("4"));
root->at(0)->AddTree(make_shared<Node>("5"));
root->at(1)->AddTree(make_shared<Node>("6"));
root->at(1)->AddTree(make_shared<Node>("7"));
root->print();
root->ReplaceChild(0,root);
root->print();
return 0;
}