binary tree height

max_depth.js

function TreeNode(val) {
    this.val = val;
    this.left = this.right = null;
}

/**
 * @param {TreeNode} root
 * @return {number}
 */
const maxDepth = root => {
  if (!root) {
    return 0;
  }

  return 1 + Math.max(maxDepth(root.left), maxDepth(root.right));
};

export default maxDepth;