C++ Recursion!
int rangeSumBST(TreeNode* root, int L, int R) {\n        if(!root || L > R)\n            return 0;\n        \n        if(root->val < L)\n            return rang
    int rangeSumBST(TreeNode* root, int L, int R) {\n        if(!root || L > R)\n            return 0;\n        \n        if(root->val < L)\n            return rangeSumBST(root->right, L, R);\n        \n        if(root->val > R)\n            return rangeSumBST(root->left, L, R);\n        \n        return root->val + rangeSumBST(root->left, L, R) + rangeSumBST(root->right, L, R);\n    }
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