LC_606_ConstructStringFromBT.cpp

/*
https://leetcode.com/problems/construct-string-from-binary-tree/
606. Construct String from Binary Tree

*/

/**
 * 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)
            return "";
        string ans = to_string(root->val);
        if(root->left)
        {
           ans+= "(" + tree2str(root->left) + ")";
        }
        else if(root->right)
          ans+= "()";
        
         if(root->right)
        {
           ans+= "(" + tree2str(root->right) + ")";
        }
        return ans;
    }
    
    string tree2str(TreeNode* root) {
        
        if(!root)
            return "";
        string ans = to_string(root->val);
        
        if(!root->left and !root->right)
            return ans;
        
        ans+= "(" + tree2str(root->left) + ")";
    
        if(root->right)
        {
           ans+= "(" + tree2str(root->right) + ")";
        }
        return ans;
    }
       

};