Range Sum of BST Problem & Solution
Given the root node of a binary search tree and two integers low and high, return the sum of values of all nodes with a value in the inclusive range [low, high].
See the range sum of BST problem on LeetCode.
C++ Solution
#pragma GCC optimize("Ofast")
#pragma GCC optimization("max-inline-insns-recursive-auto")
static const int _=[](){std::ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);return 0;}();
/**
* 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:
int rangeSumBST(TreeNode* root, int low, int high) {
if (root == nullptr) {
return 0;
}
int sum = 0;
if (root->val >= low && root->val <= high) {
sum += root->val;
}
if (root->val > low) {
sum += rangeSumBST(root->left, low, high);
}
if (root->val <= high) {
sum += rangeSumBST(root->right, low, high);
}
return sum;
}
};