> For the complete documentation index, see [llms.txt](https://jimmylin1991.gitbook.io/practice-of-algorithm-problems/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jimmylin1991.gitbook.io/practice-of-algorithm-problems/tree/783.-minimum-distance-between-bst-nodes.md).

# 783. Minimum Distance Between BST Nodes

Given a Binary Search Tree (BST) with the root node `root`, return the minimum difference between the values of any two different nodes in the tree.

**Example :**

```
Input: root = [4,2,6,1,3,null,null]
Output: 1
Explanation:
Note that root is a TreeNode object, not an array.

The given tree [4,2,6,1,3,null,null] is represented by the following diagram:

          4
        /   \
      2      6
     / \    
    1   3  

while the minimum difference in this tree is 1, it occurs between node 1 and node 2, also between node 3 and node 2.
```

**Note:**

1. The size of the BST will be between 2 and `100`.
2. The BST is always valid, each node's value is an integer, and each node's value is different.

```cpp
// Inorder Traversal Recursion
void helper(TreeNode* node, TreeNode*& pre, int& res) {
    if (!node) return;
    helper(node->left, pre, res);
    if (pre)
        res = min(res, node->val - pre->val);
    pre = node;
    helper(node->right, pre, res);
}
int minDiffInBST(TreeNode* root) { // time: O(n); space: O(h)
    int res = INT_MAX;
    TreeNode* pre = nullptr;
    helper(root, pre, res);
    return res;
}
```


---

# 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://jimmylin1991.gitbook.io/practice-of-algorithm-problems/tree/783.-minimum-distance-between-bst-nodes.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.