Quiz

Given the root of a binary tree and integers val and depth (root is at depth 1), insert a new row of nodes with value val at the specified depth. For each existing node at depth depth - 1, add new left and right children with value val; the original left subtree becomes the new left child's left subtree, and the original right subtree becomes the new right child's right subtree. If depth == 1, the new node becomes the root with the original tree as its left subtree.