Create: 1448-Count-Good-Nodes-in-Binary-Tree.ts

Author: andra961

typescript/1448-Count-Good-Nodes-in-Binary-Tree.ts

@@ -0,0 +1,21 @@
+function goodNodes(root: TreeNode | null): number {
+    // edge case
+    if (root === null) return 0;
+
+    //keep track of the count
+    let count = 0;
+
+    const dfs = (root, max) => {
+        //if value is bigger than max of path, then it is a good node
+        if (root.val >= max) count++;
+
+        //extend search to children if not null with updated max(takes current node in consideration too)
+        if (root.left !== null) dfs(root.left, Math.max(max, root.val));
+        if (root.right !== null) dfs(root.right, Math.max(max, root.val));
+    };
+
+    //starts with negative max value, because min value is just the smaller positive value in javascript
+    dfs(root, -Number.MAX_VALUE);
+
+    return count;
+}