avltree insert(int data, avltree T){
if(!T){
T=(avltree)malloc(sizeof(struct avltreeNode));
T->data=data;
T->height=0;
T->left=T->right=NULL;
// printf("%d\n",T->data);
}
else if(data < T->data){
T->left=insert(data,T->left);
if(GetHeight(T->left)-GetHeight(T->right)==2)
if(data < T->left->data)
T=SingleLeftRotation(T);
else
T=DoubleLeftRightRotation(T);
// printf("%d\n",T->data);
}
else if(data > T->data){
T->right=insert(data,T->right);
if(GetHeight(T->left)-GetHeight(T->right)==-2)
if(data > T->right->data)
T=SingleRightRotation(T);
else
T=DoubleRightLeftRotation(T);
// printf("%d\n",T->data);
}
T->height=Max(GetHeight(T->left),GetHeight(T->right))+1;
// printf("height:%d\n",T->height);
return T;
}
/*******************************************************************************
Função que faz o reequilíbrio do nó pretendido da AVL.
Function that balances the tree if necessary in each node that does not respect
the equilibrium rule, after insertion and deletion operations.
*******************************************************************************/
static void Balance (PtAVLNode *proot)
{
unsigned int LeftH, RightH;
if (*proot == NULL) return; /* subárvore vazia - empty tree */
LeftH = AVLHeight ((*proot)->PtLeft); /* altura subárvore esquerda - left subtree height */
RightH = AVLHeight ((*proot)->PtRight); /* altura subárvore direita - right subtree height */
if (LeftH - RightH == 2) /* subárvore esquerda desequilibrada? - left subtree unbalanced? */
{
LeftH = AVLHeight ((*proot)->PtLeft->PtLeft);
RightH = AVLHeight ((*proot)->PtLeft->PtRight);
if (LeftH >= RightH) SingleRightRotation (proot);
else DoubleLeftRightRotation (proot);
}
else if (RightH - LeftH == 2) /* subárvore direita desequilibrada? - right subtree unbalanced? */
{
RightH = AVLHeight ((*proot)->PtRight->PtRight);
LeftH = AVLHeight ((*proot)->PtRight->PtLeft);
if (RightH >= LeftH) SingleLeftRotation (proot);
else DoubleRightLeftRotation (proot);
}
else (*proot)->Height = LeftH > RightH ? LeftH + 1 : RightH + 1;
/* atualizar a altura do nó - updationg the node height */
}
AVLTree DoubleLeftRightRotation ( AVLTree A )
{ /* 注意：A必须有一个左子结点B，且B必须有一个右子结点C */
/* 将A、B与C做两次单旋，返回新的根结点C */
/* 将B与C做右单旋，C被返回 */
A->Left = SingleRightRotation(A->Left);
/* 将A与C做左单旋，C被返回 */
return SingleLeftRotation(A);
}
AVLTree Insert( AVLTree T, ElementType X )
{ /* 将X插入AVL树T中，并且返回调整后的AVL树 */
if ( !T ) { /* 若插入空树，则新建包含一个结点的树 */
T = (AVLTree)malloc(sizeof(struct AVLNode));
T->Data = X;
T->Height = 0;
T->Left = T->Right = NULL;
} /* if (插入空树) 结束 */
else if ( X < T->Data ) {
/* 插入T的左子树 */
T->Left = Insert( T->Left, X);
/* 如果需要左旋 */
if ( GetHeight(T->Left)-GetHeight(T->Right) == 2 )
if ( X < T->Left->Data )
T = SingleLeftRotation(T); /* 左单旋 */
else
T = DoubleLeftRightRotation(T); /* 左-右双旋 */
} /* else if (插入左子树) 结束 */
else if ( X > T->Data ) {
/* 插入T的右子树 */
T->Right = Insert( T->Right, X );
/* 如果需要右旋 */
if ( GetHeight(T->Left)-GetHeight(T->Right) == -2 )
if ( X > T->Right->Data )
T = SingleRightRotation(T); /* 右单旋 */
else
T = DoubleRightLeftRotation(T); /* 右-左双旋 */
} /* else if (插入右子树) 结束 */
/* else X == T->Data，无须插入 */
/* 别忘了更新树高 */
T->Height = Max( GetHeight(T->Left), GetHeight(T->Right) ) + 1;
return T;
}
void CObAvlTree::DoubleRightRotation( CNode* pNode )
{
SingleLeftRotation(pNode->pLChild);
SingleRightRotation(pNode);
}
void CObAvlTree::RemoveAt(POSITION position)
{
//avl tree removing.
//For a node having children, the concept model is to find the inorder successor of the removing node,
//copy the data of IOS to the removing node, then remove the IOS rather than the removing node.
//the rotation balance begins from the parent of the IOS and traces back to its ancestors.
//however, the implementation removes the true removing node so that the iterator won't point to a garbage node.
ASSERT_VALID(this);
CNode* pOldNode = (CNode*) position;
ASSERT(AfxIsValidAddress(pOldNode, sizeof(CNode)));
//block 1. regular binary tree remove, except makeing pRotateNode point to the start tracing node for rotation,
//and the bubble node's height is replaced the height of the removed node
//case 1. single child, just bubble the child the the parent place
//case 2. double children, bubble the in order successor to the parent place.
CNode* pBubbleNode = NULL;
CNode* pRotateNode = NULL;
if( pOldNode->pLChild==NULL ){
pBubbleNode = pOldNode->pRChild;
pRotateNode = pOldNode->pParent;
}else if( pOldNode->pRChild==NULL ){
pBubbleNode = pOldNode->pLChild;
pRotateNode = pOldNode->pParent;
}else{
//case 2
pBubbleNode = pOldNode->pRChild;
while( pBubbleNode->pLChild )pBubbleNode = pBubbleNode->pLChild;
//now pBubbleNode is the IOS, but if bubble node is the right child of the removing node,
//do not change the right child of the bubble node
if( pBubbleNode->pParent!=pOldNode ){ //the bubble node is more than one height below the removing node
pBubbleNode->pParent->pLChild = pBubbleNode->pRChild;
if( pBubbleNode->pRChild )pBubbleNode->pRChild->pParent=pBubbleNode->pParent;
//save the rotation place.
pRotateNode = pBubbleNode->pParent;
//link the right child of the removing node to bubble node
pBubbleNode->pRChild = pOldNode->pRChild;
pOldNode->pRChild->pParent = pBubbleNode;
}else{
pRotateNode = pBubbleNode;
}
//link the left child of the removing node to the bubble node
pBubbleNode->pLChild = pOldNode->pLChild;
pOldNode->pLChild->pParent = pBubbleNode;
//replace the height of the bubble node by the removed node
ASSERT(AfxIsValidAddress(pBubbleNode, sizeof(CNode)));
pBubbleNode->nHeight = pOldNode->nHeight;
}
CNode** ppNode=NULL;
if( pOldNode==m_pNodeRoot )ppNode = &m_pNodeRoot;
else if( pOldNode->pParent->pLChild==pOldNode )ppNode=&pOldNode->pParent->pLChild;
else ppNode=&pOldNode->pParent->pRChild;
*ppNode = pBubbleNode;
if( pBubbleNode )pBubbleNode->pParent = pOldNode->pParent;
FreeNode(pOldNode);
//block 2, avl tree balance rotation
//the loop goes upward to find the rotation node until the root node is reached or the current subtree's height is not changed.
//if a rotation is done, LOOP CONTINUE beause the height of the subtree at the rotation node may decrease,
//so the ancestors may need rotation.
//if the rotation is not done for the node, then adjust the height of the current node.
while( pRotateNode ){
int nOldHeight = NODEHEIGHT(pRotateNode);
if( NODEHEIGHT(pRotateNode->pLChild)-NODEHEIGHT(pRotateNode->pRChild)==2 ){
//left subtree is too high, rotate to right
CNode* pChildNode = pRotateNode->pLChild;
ASSERT( pChildNode!=NULL );
if( NODEHEIGHT(pChildNode->pLChild)>=NODEHEIGHT(pChildNode->pRChild) ){
SingleRightRotation( pRotateNode );
}else{
ASSERT( NODEHEIGHT(pChildNode->pLChild)<NODEHEIGHT(pChildNode->pRChild) );
DoubleRightRotation( pRotateNode );
}
//after the rotation, the pRotateNode becomes a child of the node at the rotation point
pRotateNode = pRotateNode->pParent;
}else if( NODEHEIGHT(pRotateNode->pRChild)-NODEHEIGHT(pRotateNode->pLChild)==2 ){
//right subtree is too high, rotate to left
CNode* pChildNode = pRotateNode->pRChild;
ASSERT( pChildNode!=NULL );
if( NODEHEIGHT(pChildNode->pLChild)<=NODEHEIGHT(pChildNode->pRChild) ){
SingleLeftRotation( pRotateNode );
}else{
ASSERT( NODEHEIGHT(pChildNode->pLChild)>NODEHEIGHT(pChildNode->pRChild) );
DoubleLeftRotation( pRotateNode );
}
//after the rotation, the pRotateNode becomes a child of the node at the rotation point
pRotateNode = pRotateNode->pParent;
}else{
//no rotation happend here, adjust the height
CalcHeight( pRotateNode );
}
if( nOldHeight==NODEHEIGHT(pRotateNode) ){
//since the subtree's height is not changed, STOP LOOP since the ancestors' height is maintained.
break;
}
pRotateNode = pRotateNode->pParent;
}
}
POSITION CObAvlTree::Insert(CObject* newElement)
{
ASSERT_VALID(this);
//block 1, regular binary insertion
CNode* pParent = m_pNodeRoot;
CNode** ppNode = &m_pNodeRoot;
while( *ppNode ){
pParent = *ppNode;
int nRet = CompareNode( (LPVOID)&newElement, (LPVOID)&pParent->data );
if( nRet<=0 ){
ppNode = &pParent->pLChild;
}else if( nRet>0 ){
ppNode = &pParent->pRChild;
}
}
CNode* pNewNode = NewNode(pParent, NULL, NULL);
pNewNode->data = newElement;
*ppNode = pNewNode;
//block 2, avl tree balance rotation
//the loop goes upward to find the rotation node,
//whenever a rotation is done, STOP LOOP beause the ancestors' height are the same after rotation.
//if the rotation is not yet found, then adjust the height of the current node.
CNode* pRotateNode = pParent;
while( pRotateNode ){
if( NODEHEIGHT(pRotateNode->pLChild)-NODEHEIGHT(pRotateNode->pRChild)==2 ){
//left subtree is too high, rotate to right
CNode* pChildNode = pRotateNode->pLChild;
ASSERT( pChildNode!=NULL );
if( NODEHEIGHT(pChildNode->pLChild)>NODEHEIGHT(pChildNode->pRChild) ){
SingleRightRotation( pRotateNode );
}else{
ASSERT( NODEHEIGHT(pChildNode->pLChild)<NODEHEIGHT(pChildNode->pRChild) );
DoubleRightRotation( pRotateNode );
}
break;
}else if( NODEHEIGHT(pRotateNode->pRChild)-NODEHEIGHT(pRotateNode->pLChild)==2 ){
//right subtree is too high, rotate to left
CNode* pChildNode = pRotateNode->pRChild;
ASSERT( pChildNode!=NULL );
if( NODEHEIGHT(pChildNode->pLChild)<NODEHEIGHT(pChildNode->pRChild) ){
SingleLeftRotation( pRotateNode );
}else{
ASSERT( NODEHEIGHT(pChildNode->pLChild)>NODEHEIGHT(pChildNode->pRChild) );
DoubleLeftRotation( pRotateNode );
}
break;
}
//no rotation happend here, adjust the height
CalcHeight( pRotateNode );
pRotateNode = pRotateNode->pParent;
}
/* CNode* pRotateNode = pParent;
CNode* pChildNode = pNewNode;
CNode* pGrandChdNode = pNewNode;
while( pRotateNode ){
if( pRotateNode->pLChild==pChildNode ){
//inserted in the left subtree.
if( NODEHEIGHT(pRotateNode->pLChild)-NODEHEIGHT(pRotateNode->pRChild)==2 ){
ASSERT( pChildNode!=pGrandChdNode );
if( pChildNode->pLChild==pGrandChdNode ){
SingleRightRotation( pRotateNode );
}else{
DoubleRightRotation( pRotateNode );
}
break;
}
}else{
//inserted in the right subtree
if( NODEHEIGHT(pRotateNode->pRChild)-NODEHEIGHT(pRotateNode->pLChild)==2 ){
ASSERT( pChildNode!=pGrandChdNode );
if( pChildNode->pRChild==pGrandChdNode ){
SingleRightRotation( pRotNode );
}else{
DoubleRightRotation( pRotNode );
}
break;
}
}
//no rotation happend here, adjust the height
CalcuHeight( pRotateNode );
//change the family
pGrandChdNode = pChildNode;
pChildNode = pRotateNode;
pRotateNode = pRotateNode->pParent;
}*/
/* CNode* pRotateNode = pParent;
CNode* pNode = pNewNode;
while( pRotateNode ){
CalcuHeight( pRotateNode );
if( pRotateNode->pLChild==pNode ){
//inserted in the left subtree.
if( NODEHEIGHT(pRotateNode->pLChild)-NODEHEIGHT(pRotateNode->pRChild)==2 ){
int nRet = CompareNode( (LPVOID)&newElement, (LPVOID)&pNode->data );
if( nRet<=0 ){
SingleRightRotation( pRotNode );
}else{
DoubleRightRotation( pRotNode );
}
break;
}
}else{
//inserted in the right subtree
if( NODEHEIGHT(pRotateNode->pRChild)-NODEHEIGHT(pRotateNode->pLChild)==2 ){
int nRet = CompareNode( (LPVOID)&newElement, (LPVOID)&pNode->data );
if( nRet<=0 ){
SingleRightRotation( pRotNode );
}else{
DoubleRightRotation( pRotNode );
}
break;
}
}
//no rotation happend here, adjust the height
CalcuHeight( pRotateNode );
pNode = pRotateNode;
pRotateNode = pRotateNode->pParent;
}*/
return (POSITION) pNewNode;
}
/*******************************************************************************
Função que faz a rotação dupla à direita a partir do nó pretendido da AVL.
Function that makes the left-right double rotation.
*******************************************************************************/
static void DoubleLeftRightRotation (PtAVLNode *pnode)
{
SingleLeftRotation (&(*pnode)->PtLeft);
SingleRightRotation (pnode);
}
avltree DoubleRightLeftRotation(avltree A){
A->right=SingleLeftRotation(A->right);
return SingleRightRotation(A);
}
/* 对称的右单旋与右-左双旋请自己实现 */
AVLTree DoubleRightLeftRotation(AVLTree A){
A->Right = SingleLeftRotation(A->Right);
return SingleRightRotation(A);
}
