本文共 2006 字，大约阅读时间需要 6 分钟。

以下是优化后的代码：

#include 
   
    #include 
    
     using namespace std;struct Node {    char data;    Node* Lchild;    Node* Rchild;};int max(int a, int b) {    return (a > b) ? a : b;}class Text {public:    Text() {        root = new Node;        root->Lchild = nullptr;        root->Rchild = nullptr;    }    ~Text() {        delete root;        root = nullptr;    }    void preorderTraversal() {        preorder(root);    }    int calculateDepth() {        return depth(root);    }private:    Node* root;    int leftDepth;    int rightDepth;    Node* createTree() {        char ch;        if (cin >> ch) {            Node* node = new Node;            node->data = ch;            node->Lchild = createTree();            node->Rchild = createTree();            return node;        } else {            return nullptr;        }    }    void releaseMemory(Node* node) {        if (node) {            releaseMemory(node->Lchild);            releaseMemory(node->Rchild);            delete node;        }    }    void preorder(Node* node) {        if (!node) return;        preorder(node->Lchild);        preorder(node->Rchild);    }    int depth(Node* node) {        if (!node) return 0;        int left = depth(node->Lchild);        int right = depth(node->Rchild);        return max(left, right) + 1;    }};int main() {    bool keepGoing = true;    Text tree;    while (keepGoing) {        tree.releaseMemory(root);        root = tree.createTree();        if (cin >> noskipws) {            if (!tree.root) {                keepGoing = false;            } else {                cout << tree.calculateDepth() << endl;            }        } else {            keepGoing = false;        }    }    return 0;}
    
   

优化说明：