摘要：
Given a binary tree, return the preorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, return [1,2,3]. 递归 迭代 阅读全文
摘要：
Given a binary tree, return the inorder traversal of its nodes' values. For example:Given binary tree [1,null,2,3], return [1,3,2]. 递归 迭代 阅读全文
摘要：
Given a Binary Search Tree and a target number, return true if there exist two elements in the BST such that their sum is equal to the given target. E 阅读全文
摘要：
Given a binary search tree and the lowest and highest boundaries as L and R, trim the tree so that all its elements lies in [L, R] (R >= L). You might 阅读全文