Leetcode 606 Solution

This article provides solution to leetcode question 606 (construct-string-from-binary-tree)

https://leetcode.com/problems/construct-string-from-binary-tree

Solution

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
    string ans;
public:
    void _tree2str(TreeNode* t) {
        if (t == NULL)
            return;

        ans += to_string(t->val);

        if (t->left || t->right)
        {
            ans += "(";
            _tree2str(t->left);
            ans += ")";
        }

        if (t->right)
        {
            ans += "(";
            _tree2str(t->right);
            ans += ")";
        }
    }

    string tree2str(TreeNode* t) {
        _tree2str(t);
        return ans;
    }
};