删除二叉树中具有两个子节点的节点

Removing a node with two children in a Binary Tree

本文关键字：两个子节点节点二叉树删除更新时间：2023-10-16

这就是我目前拥有的代码。我想我已经掌握了大部分逻辑，但我被困在有两个孩子的部分。我已经弄清楚了我必须使用哪种算法才能使其工作（我已经在函数底部用注释进行了注释），我只是不确定如何开始......谁能指出我正确的方向？？

这是我到目前为止所拥有的：

void BinaryTree::remove(int data){
// Is the data valid?
if(data < 0){
    cerr << data << " is not valid.  Must be a positive integer value."  << endl;
}
else{
    // Find the node
    BinNode* loc = root;
    BinNode* parent = nullptr;
    bool found = false;
    while(!found && loc != nullptr){
        if(data > loc->data){
            parent = loc;
            loc = loc->right;
        }
        else if(data < loc->data){
            parent = loc;
            loc = loc->left;
        }
        else found = true;
    }
    // If there is a parent, take care of the pointer
    if(parent != nullptr){
        if(loc->data < parent->data)
            parent->left = nullptr;
        else if(loc->data > parent->data)
            parent->right = nullptr;
    }
    // If there are children, save pointers to them
    BinNode* leftChild = nullptr;
    BinNode* rightChild = nullptr;  
    if(loc->left != nullptr)
        leftChild = loc->left;
    if(loc->right != nullptr)
        rightChild = loc->right;
    // So now pointers to the children have been saved (if they exist) and
    // parent pointers have been taken care of (if they exist) the node can be deleted
    // If no children exist simply just delete the node and return
    delete loc;
    // If one child exists
    if(leftChild != nullptr || rightChild != nullptr){  
        if(leftChild != nullptr){
            if(leftChild->data < parent->data)
                parent->left = leftChild;
            else if(leftChild->data > parent->data)
                parent->right = leftChild;
        }
        else if(rightChild != nullptr){
            if(rightChild->data < parent->data)
                parent->left = rightChild;
            else if(rightChild->data > parent->data)
                parent->right = rightChild;
        }       
    }
    // Both children exist...this sucks.
    else if(leftChild != nullptr && rightChild != nullptr){
        // Find a minimum in the right subtree
        BinNode * min = root;
        BinNode * minParent = nullptr;
        while(min->left != nullptr){
            minParent = min;
            min = min->left;
        }
        // Replace value of the node to be removed with the found minimum
        loc = new BinNode(min->data);
        // Delete the remaining duplicate node
        if(minParent != nullptr)
            minParent->left = nullptr;
        delete min;
    }
}
}

我们来了。这似乎有效。如果有人对我如何优化此问题或我需要解决的问题有任何建议，请说出来！谢谢！

void BinaryTree::remove(int data){
// Is the data valid?
if(data < 0){
    cerr << data << " is not valid.  Must be a positive integer value."  << endl;
}
else{
    // Find the node
    BinNode* loc = root;
    BinNode* parent = nullptr;
    bool found = false;
    while(!found && loc != nullptr){
        if(data > loc->data){
            parent = loc;
            loc = loc->right;
        }
        else if(data < loc->data){
            parent = loc;
            loc = loc->left;
        }
        else found = true;
    // If there are children, save pointers to them
    BinNode* leftChild = nullptr;
    BinNode* rightChild = nullptr;  
    if(loc->left != nullptr)
        leftChild = loc->left;
    if(loc->right != nullptr)
        rightChild = loc->right;
    // So now pointers to the children have been saved (if they exist) and
    // parent pointers have been taken care of (if they exist) the node can be deleted
    // If no children exist simply just delete the node and return
    // Check if two children exist
    if(leftChild != nullptr && rightChild != nullptr){
        // Find a minimum in the right subtree
        BinNode * min = loc->right;
        BinNode * minParent = loc;
        while(min->left != nullptr){
            minParent = min;
            min = min->left;
        }
        // Replace value of the node to be removed with the found minimum
        loc->data = min->data;
        // Delete the duplicate
        if(minParent != loc)
            minParent->left = nullptr;
        else minParent->right = nullptr;
        delete min;
    }
    // If one child exists
    // Need to handle if it is the root here
    // change root pointer to remaining child
    else if(leftChild != nullptr || rightChild != nullptr){ 
        // If there is a parent, take care of the pointer
        if(parent != nullptr){
            if(loc->data < parent->data)
                parent->left = nullptr;
            else if(loc->data > parent->data)
                parent->right = nullptr;
        // Now loc can be deleted
        delete loc;
        if(leftChild != nullptr){
            if(parent != nullptr){
                if(leftChild->data < parent->data)
                    parent->left = leftChild;
                else if(leftChild->data > parent->data)
                    parent->right = leftChild;
            }
            // If it is the root
            else{
                root = leftChild;
            }
        }
        else if(rightChild != nullptr){
            if(parent != nullptr){
                if(rightChild->data < parent->data)
                    parent->left = rightChild;
                else if(rightChild->data > parent->data)
                parent->right = rightChild;
            }
            // If it is the root
            else{
                root = rightChild;
            }
        }       
    }
    // If there are no children
    else if (leftChild == nullptr && rightChild == nullptr){
        // If there is a parent, take care of the pointer
        if(parent != nullptr){
            if(loc->data < parent->data)
                parent->left = nullptr;
            else if(loc->data > parent->data)
                parent->right = nullptr;
        }
        // If it is the root
        else 
            root = nullptr;
        delete loc;
    }
}