Given the root of a binary tree, collect a tree's nodes as if you were doing this: Collect all the leaf nodes. Remove all the leaf nodes. Repeat until the tree is empty. Example 1: Input: root = [1,2,3,4,5] Output: [[4,5,3],[2],[1]] Explanation: [[3,5,4],[2],[1]] and [[3,4,5],[2],[1]] are also considered correct answers since per each level it does not matter the order on which elements are returned. Example 2: Input: root = [1] Output: [[1]] Constraints: The number of nodes in the tree is in the range [1, 100]. 1 <= Node.val <= 100