#include <iostream> #include <string> using namespace std; struct TreeNode { int val; TreeNode* left; TreeNode* right; TreeNode(int x) : val(x), left(nullptr), right(nullptr) {} }; void insert(TreeNode*& root, int val) { if (root == nullptr) { root = new TreeNode(val); return; } if (val < root->val) { insert(root->left, val); } else if (val > root->val) { insert(root->right, val); } } string search(TreeNode* root, int val) { string path = "*"; while (root != nullptr) { if (val < root->val) { path += "l"; root = root->left; } else if (val > root->val) { path += "r"; root = root->right; } else { return path; } } return "Nothing."; } void remove(TreeNode*& root, int val) { if (root == nullptr) { return; } if (val < root->val) { remove(root->left, val); } else if (val > root->val) { remove(root->right, val); } else { if (root->left == nullptr) { TreeNode* temp = root; root = root->right; delete temp; } else if (root->right == nullptr) { TreeNode* temp = root; root = root->left; delete temp; } else { TreeNode* minNode = root->right; while (minNode->left != nullptr) { minNode = minNode->left; } root->val = minNode->val; remove(root->right, minNode->val); } } } int main() { int Q; cin >> Q; TreeNode* root = nullptr; for (int i = 0; i < Q; i++) { char op; int x; cin >> op >> x; if (op == '+') { insert(root, x); } else if (op == '-') { remove(root, x); } else if (op == '*') { string result = search(root, x); cout << result << endl; } } return 0; }

这段代码是一段二叉搜索树的实现，可以进行插入、删除、查找操作。其中，insert函数实现了插入操作，search函数实现了查找操作，remove函数实现了删除操作。在主函数中，根据输入的操作符进行相应的操作。其中，'+'表示插入，'-'表示删除，'*'表示查找，并输入对应的值。程序输出查找操作的结果。

相关问题

#include<iostream>using namespace std;struct TreeNode{ int val; TreeNode* left; TreeNode* right; TreeNode(int v): val(v), left(NULL), right(NULL) {}};TreeNode* buildTree(){ int val; cin >> val; if(val == -1) // 空节点 return NULL; TreeNode* root = new TreeNode(val); root->left = buildTree(); root->right = buildTree(); return root;}int main(){ cout << "请输入二叉树的先序遍历序列（空节点用-1表示）：" << endl; TreeNode* root = buildTree(); return 0;}用层次遍历该二叉树

可以使用队列来实现二叉树的层次遍历。具体步骤如下：

1. 将根节点放入队列中。

2. 当队列不为空时，取出队首节点，输出其值，并将其左右子节点（如果存在）放入队列中。

3. 重复第2步，直到队列为空。

下面是代码实现：

#include<iostream>
#include<queue>
using namespace std;

struct TreeNode{
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(int v): val(v), left(NULL), right(NULL) {}
};

TreeNode* buildTree(){
    int val;
    cin >> val;
    if(val == -1)  // 空节点
        return NULL;
    TreeNode* root = new TreeNode(val);
    root->left = buildTree();
    root->right = buildTree();
    return root;
}

void levelOrder(TreeNode* root){
    if(root == NULL)
        return;
    queue<TreeNode*> q;
    q.push(root);
    while(!q.empty()){
        TreeNode* cur = q.front();
        q.pop();
        cout << cur->val << " ";
        if(cur->left)
            q.push(cur->left);
        if(cur->right)
            q.push(cur->right);
    }
}

int main(){
    cout << "请输入二叉树的先序遍历序列（空节点用-1表示）：" << endl;
    TreeNode* root = buildTree();
    cout << "层次遍历结果为：" << endl;
    levelOrder(root);
    return 0;
}

如果输入的二叉树是这样的：

1
2
-1
-1
3
4
-1
-1
5
-1
-1

则输出的层次遍历结果为：

1 2 3 4 5

#include <iostream> #include <queue> #include<string> using namespace std; struct TreeNode { int val; TreeNode* left; TreeNode* right; TreeNode(int x) : val(x), left(NULL), right(NULL) {} }; // 递归实现先序遍历 void preorderTraversal(TreeNode* root) { if (root) { cout << root->val << " "; preorderTraversal(root->left); preorderTraversal(root->right); } } // 非递归实现层次遍历 void levelOrderTraversal(TreeNode* root) { if (!root) { return; } queue<TreeNode*> q; q.push(root); while (!q.empty()) { TreeNode* cur = q.front(); q.pop(); cout << cur->val << " "; if (cur->left) { q.push(cur->left); } if (cur->right) { q.push(cur->right); } } } int main() { // 建立二叉树 TreeNode* root = new TreeNode(65); root->left = new TreeNode(66); root->right = new TreeNode(67); root->left->left = new TreeNode(68); root->left->right = new TreeNode(69); root->left->left->left = new TreeNode(72); root->left->right->right = new TreeNode(73); root->right->left = new TreeNode(70); root->right->right = new TreeNode(71); root->right->left->left = new TreeNode(74); // 先序遍历 cout << "Preorder Traversal: "; preorderTraversal(root); cout << endl; // 层次遍历 cout << "Level Order Traversal: "; levelOrderTraversal(root); cout << endl; return 0; }怎么将代码内节点的数字改成字母

要将节点的数字改成字母，可以将 TreeNode 结构体中的 val 成员变量改为 string 类型，并将节点的值赋为相应的字母。例如，将节点的数字 65 改为字母 A，将节点的数字 66 改为字母 B，以此类推，可以将代码修改如下：

#include <iostream>
#include <queue>
#include <string>
using namespace std;

struct TreeNode {
    string val; // 将节点的值从 int 类型改为 string 类型
    TreeNode* left;
    TreeNode* right;
    TreeNode(string s) : val(s), left(NULL), right(NULL) {} // 将节点的值初始化为字符串类型
};

// 递归实现先序遍历
void preorderTraversal(TreeNode* root) {
    if (root) {
        cout << root->val << " ";
        preorderTraversal(root->left);
        preorderTraversal(root->right);
    }
}

// 非递归实现层次遍历
void levelOrderTraversal(TreeNode* root) {
    if (!root) {
        return;
    }
    queue<TreeNode*> q;
    q.push(root);
    while (!q.empty()) {
        TreeNode* cur = q.front();
        q.pop();
        cout << cur->val << " ";
        if (cur->left) {
            q.push(cur->left);
        }
        if (cur->right) {
            q.push(cur->right);
        }
    }
}

int main() {
    // 建立二叉树
    TreeNode* root = new TreeNode("A"); // 将节点的值从数字改为字母
    root->left = new TreeNode("B");
    root->right = new TreeNode("C");
    root->left->left = new TreeNode("D");
    root->left->right = new TreeNode("E");
    root->left->left->left = new TreeNode("H");
    root->left->right->right = new TreeNode("I");
    root->right->left = new TreeNode("F");
    root->right->right = new TreeNode("G");
    root->right->left->left = new TreeNode("J");

    // 先序遍历
    cout << "Preorder Traversal: ";
    preorderTraversal(root);
    cout << endl;

    // 层次遍历
    cout << "Level Order Traversal: ";
    levelOrderTraversal(root);
    cout << endl;

    return 0;
}

这样就可以将节点的数字改成相应的字母了。