Add solution #1448

Author: JoshCrozier

README.md

@@ -432,6 +432,7 @@
 1443|[Minimum Time to Collect All Apples in a Tree](./1443-minimum-time-to-collect-all-apples-in-a-tree.js)|Medium|
 1446|[Consecutive Characters](./1446-consecutive-characters.js)|Easy|
 1447|[Simplified Fractions](./1447-simplified-fractions.js)|Medium|
+1448|[Count Good Nodes in Binary Tree](./1448-count-good-nodes-in-binary-tree.js)|Medium|
 1450|[Number of Students Doing Homework at a Given Time](./1450-number-of-students-doing-homework-at-a-given-time.js)|Easy|
 1451|[Rearrange Words in a Sentence](./1451-rearrange-words-in-a-sentence.js)|Medium|
 1455|[Check If a Word Occurs As a Prefix of Any Word in a Sentence](./1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence.js)|Easy|

solutions/1448-count-good-nodes-in-binary-tree.js

@@ -0,0 +1,28 @@
+/**
+ * 1448. Count Good Nodes in Binary Tree
+ * https://leetcode.com/problems/count-good-nodes-in-binary-tree/
+ * Difficulty: Medium
+ *
+ * Given a binary tree root, a node X in the tree is named good if in the path from
+ * root to X there are no nodes with a value greater than X.
+ *
+ * Return the number of good nodes in the binary tree.
+ */
+
+/**
+ * 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)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var goodNodes = function(root, max = -Infinity) {
+  if (!root) return 0;
+  const n = root.val >= max ? 1 : 0;
+  return n + goodNodes(root.left, n ? root.val : max) + goodNodes(root.right, n ? root.val : max);
+};