Create 0938-range-sum-of-bst.js

Author: aadil42

javascript/0938-range-sum-of-bst.js

@@ -0,0 +1,31 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * DFS | Recursion
+ * Time O(n)  | Space O(n)
+ * https://leetcode.com/problems/range-sum-of-bst
+ * 
+ * @param {TreeNode} root
+ * @param {number} low
+ * @param {number} high
+ * @return {number}
+ */
+var rangeSumBST = function(root, low, high) {
+    
+    let total = 0;
+
+    const dfs = (node) => {
+        if(!node) return;
+        if(node.val >= low && node.val <= high) total += node.val;
+        dfs(node.left);
+        dfs(node.right);
+    }
+    dfs(root);
+    return total;
+};