摘要：
题目： Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthe 阅读全文
摘要：
题目： Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example:Given binary tre 阅读全文
摘要：
题目： Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree [1,2,2,3,4,4,3] is sy 阅读全文