摘要：
Problem LeetCode Given the root of a binary tree, return the preorder traversal of its nodes' values. Example 1: Input: root = [1,null,2,3] Output: [1 阅读全文
摘要：
Problem LeetCode Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf 阅读全文
摘要：
Problem LeetCode Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for th 阅读全文