更新:我无法让“平衡”工作,因为我无法让“doAVLBalance”识别成员函数“isBalanced()”、“isRightHeavy()”、“isLeftHeavy”。而且我不知道为什么!我完全尝试了 Sash 的示例(第 3 个答案),但我得到“减速不兼容”并且我无法解决这个问题......所以我尝试按照我的方式去做......它告诉我那些成员函数不存在,当他们显然做到了。
“错误:类“IntBinaryTree:TreeNode”没有成员“isRightHeavy”。我在尝试过去 4 小时后被卡住了 :(。下面更新了代码,非常感谢帮助!!
我正在创建一个基于字符串的二叉搜索树,并且需要使其成为“平衡”树。我该怎么做呢?*请帮忙!!提前致谢!
BinarySearchTree.cpp:
bool IntBinaryTree::leftRotation(TreeNode *root)
{
//TreeNode *nodePtr = root; // Can use nodePtr instead of root, better?
// root, nodePtr, this->?
if(NULL == root)
{return NULL;}
TreeNode *rightOfTheRoot = root->right;
root->right = rightOfTheRoot->left;
rightOfTheRoot->left = root;
return rightOfTheRoot;
}
bool IntBinaryTree::rightRotation(TreeNode *root)
{
if(NULL == root)
{return NULL;}
TreeNode *leftOfTheRoot = root->left;
root->left = leftOfTheRoot->right;
leftOfTheRoot->right = root;
return leftOfTheRoot;
}
bool IntBinaryTree::doAVLBalance(TreeNode *root)
{
if(NULL==root)
{return NULL;}
else if(root->isBalanced()) // Don't have "isBalanced"
{return root;}
root->left = doAVLBalance(root->left);
root->right = doAVLBalance(root->right);
getDepth(root); //Don't have this function yet
if(root->isRightHeavy()) // Don't have "isRightHeavey"
{
if(root->right->isLeftheavey())
{
root->right = rightRotation(root->right);
}
root = leftRotation(root);
}
else if(root->isLeftheavey()) // Don't have "isLeftHeavey"
{
if(root->left->isRightHeavey())
{
root->left = leftRotation(root->left);
}
root = rightRotation(root);
}
return root;
}
void IntBinaryTree::insert(TreeNode *&nodePtr, TreeNode *&newNode)
{
if(nodePtr == NULL)
nodePtr = newNode; //Insert node
else if(newNode->value < nodePtr->value)
insert(nodePtr->left, newNode); //Search left branch
else
insert(nodePtr->right, newNode); //search right branch
}
//
// Displays the number of nodes in the Tree
int IntBinaryTree::numberNodes(TreeNode *root)
{
TreeNode *nodePtr = root;
if(root == NULL)
return 0;
int count = 1; // our actual node
if(nodePtr->left !=NULL)
{ count += numberNodes(nodePtr->left);
}
if(nodePtr->right != NULL)
{
count += numberNodes(nodePtr->right);
}
return count;
}
// Insert member function
void IntBinaryTree::insertNode(string num)
{
TreeNode *newNode; // Poitner to a new node.
// Create a new node and store num in it.
newNode = new TreeNode;
newNode->value = num;
newNode->left = newNode->right = NULL;
//Insert the node.
insert(root, newNode);
}
// More member functions, etc.
BinarySearchTree.h:
class IntBinaryTree
{
private:
struct TreeNode
{
string value; // Value in the node
TreeNode *left; // Pointer to left child node
TreeNode *right; // Pointer to right child node
};
//Private Members Functions
// Removed for shortness
void displayInOrder(TreeNode *) const;
public:
TreeNode *root;
//Constructor
IntBinaryTree()
{ root = NULL; }
//Destructor
~IntBinaryTree()
{ destroySubTree(root); }
// Binary tree Operations
void insertNode(string);
// Removed for shortness
int numberNodes(TreeNode *root);
//int balancedTree(string, int, int); // TreeBalanced
bool leftRotation(TreeNode *root);
bool rightRotation(TreeNode *root);
bool doAVLBalance(TreeNode *root); // void doAVLBalance();
bool isAVLBalanced();
int calculateAndGetAVLBalanceFactor(TreeNode *root);
int getAVLBalanceFactor()
{
TreeNode *nodePtr = root; // Okay to do this? instead of just
// left->mDepth
// right->mDepth
int leftTreeDepth = (left !=NULL) ? nodePtr->left->Depth : -1;
int rightTreeDepth = (right != NULL) ? nodePtr->right->Depth : -1;
return(leftTreeDepth - rightTreeDepth);
}
bool isRightheavey() { return (getAVLBalanceFactor() <= -2); }
bool isLeftheavey() { return (getAVLBalanceFactor() >= 2); }
bool isBalanced()
{
int balanceFactor = getAVLBalanceFactor();
return (balanceFactor >= -1 && balanceFactor <= 1);
}
int getDepth(TreeNode *root); // getDepth
void displayInOrder() const
{ displayInOrder(root); }
// Removed for shortness
};