## 530. Minimum Absolute Difference in BST

Given a binary search tree with non-negative values, find the minimum absolute difference between values of any two nodes.

Example:

```Input:

1
\
3
/
2

Output:
1

Explanation:
The minimum absolute difference is 1, which is the difference between 2 and 1 (or between 2 and 3).
```

Note:

## Rust Solution

``````struct Solution;
use rustgym_util::*;

trait Inorder {
fn inorder(&self, prev: &mut Option<i32>, min: &mut i32);
}

fn inorder(&self, prev: &mut Option<i32>, min: &mut i32) {
if let Some(node) = self {
let node = node.borrow();
Self::inorder(&node.left, prev, min);
if let Some(prev_val) = prev.as_mut() {
*min = (node.val - *prev_val).abs().min(*min);
*prev_val = node.val;
} else {
*prev = Some(node.val);
}
Self::inorder(&node.right, prev, min);
}
}
}

impl Solution {
fn get_minimum_difference(root: TreeLink) -> i32 {
let mut min = i32::MAX;
let mut prev: Option<i32> = None;
root.inorder(&mut prev, &mut min);
min
}
}

#[test]
fn test() {
let root = tree!(1, None, tree!(3, tree!(2), None));
assert_eq!(Solution::get_minimum_difference(root), 1);
}
``````

Having problems with this solution? Click here to submit an issue on github.