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rustgym/leetcode/
_530_minimum_absolute_difference_in_bst.rs

1struct Solution;
2use rustgym_util::*;
3
4trait Inorder {
5    fn inorder(&self, prev: &mut Option<i32>, min: &mut i32);
6}
7
8impl Inorder for TreeLink {
9    fn inorder(&self, prev: &mut Option<i32>, min: &mut i32) {
10        if let Some(node) = self {
11            let node = node.borrow();
12            Self::inorder(&node.left, prev, min);
13            if let Some(prev_val) = prev.as_mut() {
14                *min = (node.val - *prev_val).abs().min(*min);
15                *prev_val = node.val;
16            } else {
17                *prev = Some(node.val);
18            }
19            Self::inorder(&node.right, prev, min);
20        }
21    }
22}
23
24impl Solution {
25    fn get_minimum_difference(root: TreeLink) -> i32 {
26        let mut min = i32::MAX;
27        let mut prev: Option<i32> = None;
28        root.inorder(&mut prev, &mut min);
29        min
30    }
31}
32
33#[test]
34fn test() {
35    let root = tree!(1, None, tree!(3, tree!(2), None));
36    assert_eq!(Solution::get_minimum_difference(root), 1);
37}