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;
    }
};