摘要：
Print a binary tree in an m*n 2D string array following these rules: Example 1: Example 2: Example 3: Note: The height of binary tree is in the range 阅读全文
摘要：
Given an integer array with no duplicates. A maximum tree building on this array is defined as follow: Construct the maximum tree by the given array a 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