struct element{
       int label;
       int used;
};

struct bt{
       element elements[10000];
};

typedef int node;

bt* InitB(int x, bt* T){
    if(T) delete T;
    T = new bt;
    for(int i = 0; i < 10000; i++)
        T->elements[i].used = 0;
    T->elements[1].label = x;
    T->elements[1].used = 1;
    return T;
}

void CreateLeftB(int x, node n, bt* T){
     if(T->elements[n].used == 0 || T->elements[2*n].used == 1) {
           cout << "Greska" << endl << endl;
           return;
     }
     T->elements[2*n].used = 1;
     T->elements[2*n].label = x;
}

void CreateRightB(int x, node n, bt* T){
        if(T->elements[n].used == 0 || T->elements[2*n+1].used == 1){
        cout << "Greska" << endl << endl;
        return;
    }
    T->elements[2*n+1].used = 1;
    T->elements[2*n+1].label = x;
}

node LeftChildB(node n, bt* T){
     if(T->elements[n].used == 0)
           return 0;
     if(T->elements[2*n].used == 1)
           return 2*n;
     else return 0;
}

node RightChildB(node n, bt* T){
     if(T->elements[n].used == 0) return 0;
     if(T->elements[2*n+1].used == 1) return 2*n+1;
     else return 0;
}

node ParentB(node n, bt* T){
     if(n == 1) return 0;
     if(n%2) n--;
     return n/2;
}

int LabelB(node n, bt* T){
          return T->elements[n].label;
}

void ChangeLabelB(int x, node n, bt* T){
     if(T->elements[n].used == 0) return;
     T->elements[n].label = x;
}

node RootB(bt* T){
     if(T->elements[1].used == 0) return 0;
     return 1;
}

void DeleteB(node n, bt* T){
    T->elements[n].used = 0;
        if (LeftChildB(n, T)) DeleteB(LeftChildB(n, T), T);
        if (RightChildB(n, T)) DeleteB(RightChildB(n, T), T);
}