https://leetcode.com/problems/add-one-row-to-tree/?envType=daily-question&envId=2024-08-23Given the root of a binary tree and two integers val and depth, add a row of nodes with value val at the given depth depth.Note that the root node is at depth 1.The adding rule is:Given the integer depth, for each not null tree node cur at the depth depth - 1, create two tree nodes with value val as cur's l..
