Range Sum of BST.cpp

/*
https://leetcode.com/problems/range-sum-of-bst/

*/

/**
 * 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 {
public:
    int rangeSumBST(TreeNode* root, int L, int R) {
        if(root==NULL) return 0;
        if(root->val<L) return rangeSumBST(root->right,L,R);
        if(root->val>R) return rangeSumBST(root->left,L,R);
        return root->val+rangeSumBST(root->left,L,R)+rangeSumBST(root->right,L,R);
    }
};