> For the complete documentation index, see [llms.txt](https://dfine.gitbook.io/leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dfine.gitbook.io/leetcode/538.convert_bst_to_greater_tree.md).

# 538.Convert BST to Greater Tree

**538.Convert BST to Greater Tree**

难度:Easy

> 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
```

需要将二叉树从小到大排列，然后逐个相加，由于是BST，因此中序遍历即可。

```
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
private:
    stack<TreeNode*> all;
    void traversal(TreeNode* root)
    {
        if(!root) return;
        if(root->left) traversal(root->left);
        all.push(root);
        if(root->right) traversal(root->right);
    }
public:
    TreeNode* convertBST(TreeNode* root) {
        if(!root) return 0;
         traversal(root);
        int s=0;
       //cout<<all.size()<<endl;
        while(!all.empty())
        {
             s+=all.top()->val;
        //  cout<<s<<endl;
           all.top()->val=s;
            all.pop();
        }
        
            
        return root;
    }
};
```

> 执行用时 : 56 ms, 在Convert BST to Greater Tree的C++提交中击败了91.81% 的用户\
> 内存消耗 : 24.2 MB, 在Convert BST to Greater Tree的C++提交中击败了79.10% 的用户


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://dfine.gitbook.io/leetcode/538.convert_bst_to_greater_tree.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.