1448-Count-Good-Nodes-in-Binary-Tree.js

function goodNodes(root) {
    let total = 0;

    function traverse(node, prev) {
        if (!node) return;

        if (node.left || node.right) {
            traverse(node.left, Math.max(node.val, prev));
            traverse(node.right, Math.max(node.val, prev));
        }

        if (node.val >= prev) {
            total += 1;
        }
    }

    traverse(root, root.val);

    return total;
}