Add One Row to Tree
The problem is to add a new row of nodes at a given depth in a binary tree. Here’s a Python implementation for the addOneRow
method, based on the constraints and the rules you provided:


This code uses a recursive helper function to traverse the tree and find the nodes at depth  1
. Then, it inserts the new nodes with the given value, attaching the original left and right subtrees to the corresponding new nodes as required. If the specified depth is 1, a new root is created, and the original tree becomes the left subtree of this new root.


The function adds a new row to a binary tree at a specified depth, with all nodes in that row having a specified value. Here are some components that can help to understand and categorize this problem:
This problem belongs to the domain of binary trees and tree manipulation.
What Components:
 Input:
root
, representing the root node of a given binary tree.val
, an integer representing the value of the new nodes.depth
, an integer representing the depth at which the new row should be added.
 Output: The root node of the modified tree after adding the new row.
 Constraints: Constraints on the values of the nodes, the value to be added, and the depth of the tree.
Classifying the Problem:
 Data Structure Used: Binary Tree.
 Operations: Insertion, Traversal.
 Algorithms and Techniques: This could be solved using a levelorder traversal or a depthfirst traversal to find the nodes at the required depth. From there, new nodes can be inserted according to the rules described.
Slightly Simpler Problem: If you’re looking for something slightly simpler related to this problem, you might consider:
 Adding a new node at a specific position in the tree, rather than an entire row.
 Finding the nodes at a specific depth without performing the insertions.
These simpler tasks build up the skills and understanding necessary to tackle the original problem.