### Adding one row to a Binary Tree

Love tree problems, once you get it right, there are usually very few corner cases (other than the d=1, which was mentioned in the problem description anyways). Here it is, and code is down below. Song that goes along well with this problem: https://www.youtube.com/watch?v=7HHBFkdHyRU&list=PL9LM05lDUoXqVDYM5MIM4owPiYLCm_Ucm&index=385 Cheers, ACC. https://leetcode.com/problems/add-one-row-to-tree/ 623. Add One Row to Tree Medium 378 119 Add to List Share Given the root of a binary tree, then value v and depth d , you need to add a row of nodes with value v at the given depth d . The root node is at depth 1. The adding rule is: given a positive integer depth d , for each NOT null tree nodes N in depth d-1 , create two tree nodes with value v as N's left subtree root and right subtree root. And N's original left subtree should be the left subtree of the new left subtree root, its original right subtree should be the right subtree o