static TLDNode *balance(TLDNode *node)
{
int diff;
diff = getDiff(node);
if (diff > 1)
{
if (getDiff(node->left) > 0)
{
node = leftLeftRotation(node);
}
else
{
node = leftRightRotation(node);
}
}
else if (diff < -1)
{
if (getDiff(node->right) > 0)
{
node = rightLeftRotation(node);
}
else
{
node = rightRightRotation(node);
}
}
return node;
}
nodeT* insertNew(nodeT*root, int value)
{
///make the actual insertion
if (root==NULL) return createNode(value);
if (value<root->data)
root->left=insertNew(root->left,value);
else
if (value>root->data)
root->right=insertNew(root->right,value);
///update height
root->height=max(height(root->left),height(root->right))+1;
///calculating balance factor
int bF=balanceFactor(root);
///make the rotation, if necessary
if (bF==-2)
{
if (root->right->data<value) singleLeftRotation(&root);
if (root->right->data>value) rightLeftRotation(&root);
}
else
{
if (bF==2)
{
if (root->left->data>value) singleRightRotation(&root);
if (root->left->data<value) leftRightRotation(&root);
}
}
return root;
}
bool AVLTree<T>::addNode(T k, T val)
{
bool isSuccess = BSTree<T>::addNode(k, val);
if (isSuccess)
{
NodePointer ptr = searchNode(k);
if (ptr != root)
{
NodePointer preParent = ptr->parent;
if (preParent != root)
{
NodePointer prePreParent = preParent->parent;
if (prePreParent == root)
{
if (getHeight(prePreParent->left) - getHeight(prePreParent->right) == 2)
{
if (ptr == preParent->left)
{
root = leftLeftRotation(prePreParent);
}
else
{
root = leftRightRotation(prePreParent);
}
}
else if (getHeight(prePreParent->right) - getHeight(prePreParent->left) == 2)
{
if (ptr == preParent->left)
{
root = rightLeftRotation(prePreParent);
}
else
{
root = rightRightRotation(prePreParent);
}
}
}
else
{
NodePointer prePrePreParent = prePreParent->parent;
if (getHeight(prePreParent->left) - getHeight(prePreParent->right) == 2)
{
if (prePreParent == prePrePreParent->left)
{
if (ptr == preParent->left)
{
prePrePreParent->left = leftLeftRotation(prePreParent);
}
else
{
prePrePreParent->left = leftRightRotation(prePreParent);
}
}
else
{
if (ptr == preParent->left)
{
prePrePreParent->right = leftLeftRotation(prePreParent);
}
else
{
prePrePreParent->right = leftRightRotation(prePreParent);
}
}
}
else if (getHeight(prePreParent->right) - getHeight(prePreParent->left) == 2)
{
if (prePreParent == prePrePreParent->left)
{
if (ptr == preParent->left)
{
prePrePreParent->left = rightLeftRotation(prePreParent);
}
else
{
prePrePreParent->left = rightRightRotation(prePreParent);
}
}
else
{
if (ptr == preParent->left)
{
prePrePreParent->right = rightLeftRotation(prePreParent);
}
else
{
prePrePreParent->right = rightRightRotation(prePreParent);
}
}
}
}
}
}
}
return isSuccess;
}
bool AVLTree<T>::delNode(T k)
{
bool isSuccess = true;
NodePointer ptr = searchNode(k);
NodePointer preParent = NULL;
if (ptr != NULL)
{
if (ptr == root)
{
BSTree<T>::delNode(k);
// only left left exist
if (getHeight(root->left) - getHeight(root->right) == 2)
{
root = leftLeftRotation(root);
}
}
else
{
NodePointer lNode = NULL, rNode = NULL;
preParent = ptr->parent;
if (preParent == root)
{
BSTree<T>::delNode(k);
lNode = root->left;
rNode = root->right;
if (getHeight(preParent->left) - getHeight(preParent->right) == 2)
{
if (getHeight(lNode->left) >= getHeight(lNode->right))
{
root = leftLeftRotation(preParent);
}
else
{
root = leftRightRotation(preParent);
}
}
else if (getHeight(preParent->right) - getHeight(preParent->left) == 2)
{
if (getHeight(rNode->right) >= getHeight(rNode->left))
{
root = rightRightRotation(preParent);
}
else
{
root = rightLeftRotation(preParent);
}
}
}
else
{
NodePointer prePreParent = NULL;
NodePointer lNode = NULL, rNode = NULL;
BSTree<T>::delNode(k);
// 这里需要递归查找不平衡点,以防止高层结点不平衡而低层结点平衡的情况
NodePointer tmpPtr = findImbalanceNode(preParent);
if (tmpPtr != NULL)
{
if (tmpPtr == root)
{
lNode = tmpPtr->left;
rNode = tmpPtr->right;
if (getHeight(tmpPtr->left) - getHeight(tmpPtr->right) == 2)
{
if (getHeight(lNode->left) >= getHeight(lNode->right))
{
root = leftLeftRotation(tmpPtr);
}
else
{
root = leftRightRotation(tmpPtr);
}
}
else if (getHeight(tmpPtr->right) - getHeight(tmpPtr->left) == 2)
{
if (getHeight(rNode->right) >= getHeight(rNode->left))
{
root = rightRightRotation(tmpPtr);
}
else
{
root = rightLeftRotation(tmpPtr);
}
}
}
else
{
prePreParent = tmpPtr->parent;
lNode = tmpPtr->left;
rNode = tmpPtr->right;
if (getHeight(tmpPtr->left) - getHeight(tmpPtr->right) == 2)
{
if (tmpPtr == prePreParent->left)
{
if (getHeight(lNode->left) >= getHeight(lNode->right))
{
prePreParent->left = leftLeftRotation(tmpPtr);
}
else
{
prePreParent->left = leftRightRotation(tmpPtr);
}
}
else
{
if (getHeight(lNode->left) >= getHeight(lNode->right))
{
prePreParent->right = leftLeftRotation(tmpPtr);
}
else
{
prePreParent->right = leftRightRotation(tmpPtr);
}
}
}
else if (getHeight(tmpPtr->right) - getHeight(tmpPtr->left) == 2)
{
if (tmpPtr == prePreParent->left)
{
if (getHeight(rNode->right) >= getHeight(rNode->left))
{
prePreParent->left = rightRightRotation(tmpPtr);
}
else
{
prePreParent->left = rightLeftRotation(tmpPtr);
}
}
else
{
if (getHeight(rNode->right) >= getHeight(rNode->left))
{
prePreParent->right = rightRightRotation(tmpPtr);
}
else
{
prePreParent->right = rightLeftRotation(tmpPtr);
}
}
}
}
}
}
}
}
else
{
isSuccess = false;
}
return isSuccess;
}