struct element {
    int label;
    element *left,*right;
};
 
typedef element *node;
typedef element bt;
 
node ParentB(node n, bt* T) {
    if (n == T) return NULL;
        node roditelj = NULL;
        if (T->left) {
                if (T->left == n) return T;
                else roditelj =  ParentB(n, T->left);
        }
        if(T->right) {
                if (T->right == n) return T;
                else roditelj = ParentB(n, T->right);
        }       
        return roditelj;
}
 
node LeftChildB(node n, bt* T) {
    if(!n || !n->left) return NULL;
    return n->left; 
}
 
node RightChildB(node n, bt* T) {
    if(!n || !n->right) return NULL;
    return n->right; 
}
 
int LabelB(node n, bt* T) {
    return n->label;
}
 
void ChangeLabelB(int x, node n, bt* T) {
    if(!n) return;
    n->label = x;
}
 
node RootB(bt* T) {
    if(!T) return NULL;
    return T;
}
 
void CreateLeftB(int x, node n, bt* T) {
    if(n->left) {
        cout << "Greska" << endl << endl;
        return;
    }
    node novi = new element;
    n->left = novi;
    novi->label = x;
    novi->left = NULL;
    novi->right = NULL;
}
 
void CreateRightB(int x, node n, bt* T) {
    if(n->right) {
        cout << "Greska" << endl << endl;
        return;
    }
    node novi = new element;
    n->right = novi;
    novi->label = x;
    novi->left = NULL;
    novi->right = NULL;
}
 
void DeleteB(node n, bt* T) {
    static bool jednom = false;
    if(!jednom) {
      node roditelj = ParentB(n, T);
      if(roditelj->left == n) roditelj->left = NULL;
      else roditelj->right = NULL;
      jednom = true;
    }
 
    if(n->left) DeleteB(n->left, T);
    if(n->right) DeleteB(n->right, T);
    delete n;
}
 
bt* InitB(int x, bt* T) {
    T = new element;
    T->label = x;
    T->left = NULL;
    T->right = NULL;
    return T;
}