C++ Super-Simple Recursive Easiest Sol
\nclass Solution {\npublic:\n    void rec(TreeNode* root, int low, int high) {\n        if (!root) return;\n        if (root->val <= high && root->val >= low) r
```\nclass Solution {\npublic:\n    void rec(TreeNode* root, int low, int high) {\n        if (!root) return;\n        if (root->val <= high && root->val >= low) res+=root->val;\n        rec(root->left, low, high);\n        rec(root->right, low, high);\n    }\n    int rangeSumBST(TreeNode* root, int low, int high) {\n        rec(root, low, high);\n        return res;\n    }\n    \nprivate:\n    int res = 0;\n};\n```\n**Like it? please upvote...**
['C']