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RangeSumBST.java
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RangeSumBST.java
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//https://leetcode.com/problems/range-sum-of-bst/
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
class Solution {
int sum;
public int rangeSumBST(TreeNode root, int low, int high) {
sum = 0;
if(root == null) return sum;
rangeSumHelper(root,low,high);
return sum;
}
public void rangeSumHelper(TreeNode node, int low, int high){
if(node == null) return;
int val = node.val;
if(node.val >= low && node.val <= high){
sum+=val;
}
if(val >= low){
rangeSumHelper(node.left,low,high);
}
if(val <= high){
rangeSumHelper(node.right,low,high);
}
}
}