定制商品的网站建设网站开发费计入什么科目

链接: 根据二叉树创建字符串

题目描述

算法分析

当单纯的按照前序遍历输出后，我们只要对（）进行一些修改就好

编程代码

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     TreeNode *left;*     TreeNode *right;*     TreeNode() : val(0), left(nullptr), right(nullptr) {}*     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}*     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
public:string tree2str(TreeNode* root) {if(root == nullptr){return "";}string s = to_string(root->val);if(root->left == nullptr && root->right || root->left){s += "(";s+=tree2str(root->left);s += ")";}if(root->right != nullptr){s += "(";s+=tree2str(root->right);s += ")";}return s;}
};