T BST<T>::remove_root() {
if (root == NULL) throw 3; //no root
T retData = root->get_data();
T maxData;
BinaryNode<T>* tmpNode;
if (root->get_lhs() == NULL){
BinaryNode<T> *tmpRoot = root;
root = root->get_rhs();
delete tmpRoot;
return retData;
}
tmpNode = find_max(root->get_lhs());
maxData = tmpNode->get_data();
if(remove(maxData) != maxData) throw 2; //removed the wrong data
root->set_data(maxData);
return retData;
throw 1;
}
T BST<T>::remove(T item) {
// remember to take care of the root case
BinaryNode<T> *our_parent = NULL;
BinaryNode<T> *our_guy = root;
BinaryNode<T> *tmp;
T our_data;
while (our_guy != NULL) { // Traverse the tree down some path
if (item == our_guy->get_data())
break;
else if (item < our_guy->get_data()){ // Go left
our_parent = our_guy;
our_guy = our_guy->get_lhs();
}
else{ // Go right
our_parent = our_guy;
our_guy = our_guy->get_rhs();
}
}
if (our_guy == NULL){
throw 1; // item not found
return our_data; //VS
}
//now we know our item is inside our BST
// NOW WE CAN GET TO OUR 3 CASES OF DELETING. WOOOO
our_data = our_guy->get_data();
if (our_guy == root){
our_data = remove_root();
return our_data;
}
if (our_guy->get_rhs() == NULL && our_guy->get_lhs() == NULL){ //no children lol
if (our_parent->get_rhs() == our_guy){ //we want to NULL the rhs
delete our_parent->get_rhs();
our_parent->set_rhs(NULL);
return our_data;
}
else{ //else, NULL lhs
delete our_parent->get_lhs();
our_parent->set_lhs(NULL);
return our_data;
}
}
else if (our_guy->get_rhs() == NULL && our_guy->get_lhs() != NULL){ // one child -> our lhs is a kid
tmp = our_guy->get_lhs(); //saved the child in tmp
if (our_parent->get_rhs() == our_guy){
delete our_parent->get_rhs();
our_parent->set_rhs(tmp);
return our_data;
}
else{ //else, NULL lhs
delete our_parent->get_lhs();
our_parent->set_lhs(tmp);
return our_data;
}
}
else if (our_guy->get_lhs() == NULL && our_guy->get_rhs() != NULL){
tmp = our_guy->get_rhs(); //saved the child in tmp
if (our_parent->get_rhs() == our_guy){
delete our_parent->get_rhs();
our_parent->set_rhs(tmp);
return our_data;
}
else{ //else, NULL lhs
delete our_parent->get_lhs();
our_parent->set_lhs(tmp);
return our_data;
}
}
else{ //two child case
// saving max data into an int or someshit, then removing max's shit, then overwriting the data
BinaryNode<T> *max;
max = find_max(our_guy->get_lhs());
T max_data = max->get_data();
remove(max->get_data());
our_guy->set_data(max_data);
return our_data;
}
// TODO: Implement this function
throw 1;
}
