摘要： 题目： Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next level 阅读全文

摘要： 题目: Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique 阅读全文

摘要： 题目： Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return 阅读全文