Given the root of a binary search tree, and an integer k, return the kth smallest value (1-indexed) of all the values of the nodes in the tree. For the following BST and k=3, the expected output is 4 . Question 3: Write the following method List>> levelorder (BTNode root), which, given the root of a binary tree, will return the level order traversal of its nodes' values. (i.e., from left to right, level by level). For the following binary tree, the output list should be: [[3],[9,20],[15,7]]