Transform a BST to greater sum tree

题目如下: Given the root of a binary search tree with distinct values, modify it so that every node has a new value equal to the sum of the values of the original tree that are greater than or equal to node.val. As a reminder, a binary search tree is a t

判断一颗树是不是二分查找树,非常经典基础的一个算法. 我很久之前第一次做的时候,是先求出来了树的前序遍历的结果,然后判断这个数组排序后是否和排序前相同,还要判断重复虾米的,很纠结的一种做法. 后来思考了一下怎么用递归的思路做,觉得应该根据定义返回两个子树的最大值和最小值,写了一会代码,发现好麻烦,不太对的样子. 后来看了题解,发现是用了一种反向的思维,把上下界从树的顶端传下去,而不是自下而上的约束.作者太机智了. 1 /** 2 * Definition for binary tree 3 *

Given a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus sum of all keys greater than the original key in BST. Example: Input: The root of a Binary Search Tree like thi

Given a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus sum of all keys greater than the original key in BST. Example: Input: The root of a Binary Search Tree like thi

Given a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus sum of all keys greater than the original key in BST.Example Given a binary search Tree ｀{5,2,13}｀: 5 / 2 13 Re

Given a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus sum of all keys greater than the original key in BST. Example: Input: The root of a Binary Search Tree like thi

Given a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus sum of all keys greater than the original key in BST. Example: Input: The root of a Binary Search Tree like thi

Level: ??Easy 题目描述: Given a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus sum of all keys greater than the original key in BST. Example: Input: The root of a Binary

给定一个二叉搜索树(Binary Search Tree),把它转换成为累加树(Greater Tree),使得每个节点的值是原来的节点值加上所有大于它的节点值之和.例如:输入: 二叉搜索树:              5            /   \           2     13输出: 转换为累加树:             18            /   \          20     13详见:https://leetcode.com/problems/convert-