Given a binary tree, return the inorder traversal of its nodes' values. Example: Input: [1,null,2,3]1\2/3Output: [1,3,2] Follow up: Recursive solution is trivial, could you do it iteratively? 第一次

Given a set of distinct integers, nums, return all possible subsets (the power set). Note: The solution set must not contain duplicate subsets. Example: Input: nums = [1,2,3]Output:[[3],[1],[2],[