摘要：
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 and alternate between). 阅读全文
摘要：
Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). 阅读全文
摘要：
Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). 阅读全文
摘要：
Given two binary trees, write a function to check if they are equal or not. 阅读全文
摘要：
Two elements of a binary search tree (BST) are swapped by mistake. 阅读全文
摘要：
Given a binary tree, determine if it is a valid binary search tree (BST). 阅读全文
摘要：
Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. 阅读全文
摘要：
Given a binary tree, return the inorder traversal of its nodes' values. 阅读全文
摘要：
Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. 阅读全文
摘要：
Given n, how many structurally unique BST's (binary search trees) that store values 1...n? 阅读全文