/*
* Balance the tree. Start balancing from the given node.
*/
void AVL_tree::balance(AVL_tree::Node *node) {
Node *tmp = NULL;
int diff = 0, diff2 = 0;;
while (node != NULL) {
diff = balance_index(node);
if (diff == 2) {
tmp = node->left_child;
diff2 = balance_index(tmp);
// Double rotation situation.
if (diff2 == -1) {
rotate_left(tmp->right_child);
}
rotate_right(node->left_child);
// node->parent is a new root of the subtree.
// Update heights to the root.
update_heights(node->parent);
break;
}
else if (diff == -2) {
tmp = node->right_child;
diff2 = balance_index(tmp);
// Double rotation situation.
if (diff2 == 1) {
rotate_right(tmp->left_child);
}
rotate_left(node->right_child);
// node->parent is a new root of the subtree.
// Update heights to the root.
update_heights(node->parent);
break;
}
// If subtree is balanced, just update node's height.
// Check parent subtree.
node->height = 1 + std::max(height(node->left_child),
height(node->right_child));
node = node->parent;
}
}
int insert(AVL **r,int data)
{
/*AVL *ptr;
AVL *parent;
ptr=parent=*r;*/
AVL *nNode=createAvlNode(data);
if(!nNode)
return 0;
else if(*r==NULL)
{
*r=nNode;
return 1;
}
if(data < (*r)->value)
{
insert(&((*r)->left),data);
cal_height(*r);
//printf("value : %d hieght : %d",(*r)->value,(*r)->height);
if(diff_height(*r)==2)
{
if(data < (*r)->left->value) //LL IMBALANCE
RightRo(r);
else //LR IMBALANCE
{
LeftRo(&((*r)->left));
RightRo(r);
}
}
update_heights(*r);
}
if(data > (*r)->value)
{
insert(&((*r)->right),data);
cal_height(*r);
//printf("value : %d hieght : %d",(*r)->value,(*r)->height);
if(diff_height(*r)==2)
{
if(data < (*r)->right->value) //RR IMBALANCE
LeftRo(r);
else //LR IMBALANCE
{
RightRo(&((*r)->right));
LeftRo(r);
}
}
update_heights(*r);
}
}
