Range Sum of BST
Given the root node of a binary search tree, return the sum of values of all nodes with value between L and R (inclusive).
The binary search tree is guaranteed to have unique values.
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Example 1:
Input: root = [10,5,15,3,7,null,18], L = 7, R = 15
Output: 32
Example 2:
Input: root = [10,5,15,3,7,13,18,1,null,6], L = 6, R = 10
Output: 23
Java Solution
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/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public int sum;
public Solution(){
sum = 0;
}
public int rangeSumBST(TreeNode root, int L, int R) {
DFS(root, L, R);
return sum;
}
public void DFS(TreeNode root, int L, int R){
if(root != null){
if(root.val >= L && root.val <= R){
sum+=root.val;
}
if(root.val > L){
DFS(root.left, L, R);
}
if(root.val < R){
DFS(root.right, L, R);
}
}
}
}
