feat: add rust solution to lc problem: No.0530 (doocs#1331)

Author: xzhseh

solution/0500-0599/0530.Minimum Absolute Difference in BST/README.md

@@ -156,6 +156,55 @@ public:
 };
 ```
 
+### **Rust**
+
+```rust
+// Definition for a binary tree node.
+// #[derive(Debug, PartialEq, Eq)]
+// pub struct TreeNode {
+//   pub val: i32,
+//   pub left: Option<Rc<RefCell<TreeNode>>>,
+//   pub right: Option<Rc<RefCell<TreeNode>>>,
+// }
+// 
+// impl TreeNode {
+//   #[inline]
+//   pub fn new(val: i32) -> Self {
+//     TreeNode {
+//       val,
+//       left: None,
+//       right: None
+//     }
+//   }
+// }
+use std::rc::Rc;
+use std::cell::RefCell;
+impl Solution {
+    #[allow(dead_code)]
+    pub fn get_minimum_difference(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
+        let mut ret = i32::MAX;
+        let mut prev = i32::MAX;
+        Self::traverse(root, &mut prev, &mut ret);
+        ret
+    }
+
+    #[allow(dead_code)]
+    fn traverse(root: Option<Rc<RefCell<TreeNode>>>, prev: &mut i32, ans: &mut i32) {
+        let left = root.as_ref().unwrap().borrow().left.clone();
+        let right = root.as_ref().unwrap().borrow().right.clone();
+        let val = root.as_ref().unwrap().borrow().val;
+        if !left.is_none() {
+            Self::traverse(left.clone(), prev, ans);
+        }
+        *ans = std::cmp::min(*ans, (*prev - val).abs());
+        *prev = val;
+        if !right.is_none() {
+            Self::traverse(right.clone(), prev, ans);
+        }
+    }
+}
+```
+
 ### **Go**
 
 ```go

solution/0500-0599/0530.Minimum Absolute Difference in BST/README_EN.md

@@ -139,6 +139,55 @@ public:
 };
 ```
 
+### **Rust**
+
+```rust
+// Definition for a binary tree node.
+// #[derive(Debug, PartialEq, Eq)]
+// pub struct TreeNode {
+//   pub val: i32,
+//   pub left: Option<Rc<RefCell<TreeNode>>>,
+//   pub right: Option<Rc<RefCell<TreeNode>>>,
+// }
+// 
+// impl TreeNode {
+//   #[inline]
+//   pub fn new(val: i32) -> Self {
+//     TreeNode {
+//       val,
+//       left: None,
+//       right: None
+//     }
+//   }
+// }
+use std::rc::Rc;
+use std::cell::RefCell;
+impl Solution {
+    #[allow(dead_code)]
+    pub fn get_minimum_difference(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
+        let mut ret = i32::MAX;
+        let mut prev = i32::MAX;
+        Self::traverse(root, &mut prev, &mut ret);
+        ret
+    }
+
+    #[allow(dead_code)]
+    fn traverse(root: Option<Rc<RefCell<TreeNode>>>, prev: &mut i32, ans: &mut i32) {
+        let left = root.as_ref().unwrap().borrow().left.clone();
+        let right = root.as_ref().unwrap().borrow().right.clone();
+        let val = root.as_ref().unwrap().borrow().val;
+        if !left.is_none() {
+            Self::traverse(left.clone(), prev, ans);
+        }
+        *ans = std::cmp::min(*ans, (*prev - val).abs());
+        *prev = val;
+        if !right.is_none() {
+            Self::traverse(right.clone(), prev, ans);
+        }
+    }
+}
+```
+
 ### **Go**
 
 ```go

solution/0500-0599/0530.Minimum Absolute Difference in BST/Solution.rs

@@ -0,0 +1,44 @@
+// Definition for a binary tree node.
+// #[derive(Debug, PartialEq, Eq)]
+// pub struct TreeNode {
+//   pub val: i32,
+//   pub left: Option<Rc<RefCell<TreeNode>>>,
+//   pub right: Option<Rc<RefCell<TreeNode>>>,
+// }
+// 
+// impl TreeNode {
+//   #[inline]
+//   pub fn new(val: i32) -> Self {
+//     TreeNode {
+//       val,
+//       left: None,
+//       right: None
+//     }
+//   }
+// }
+use std::rc::Rc;
+use std::cell::RefCell;
+impl Solution {
+    #[allow(dead_code)]
+    pub fn get_minimum_difference(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
+        let mut ret = i32::MAX;
+        let mut prev = i32::MAX;
+        Self::traverse(root, &mut prev, &mut ret);
+        ret
+    }
+
+    #[allow(dead_code)]
+    fn traverse(root: Option<Rc<RefCell<TreeNode>>>, prev: &mut i32, ans: &mut i32) {
+        let left = root.as_ref().unwrap().borrow().left.clone();
+        let right = root.as_ref().unwrap().borrow().right.clone();
+        let val = root.as_ref().unwrap().borrow().val;
+        if !left.is_none() {
+            Self::traverse(left.clone(), prev, ans);
+        }
+        *ans = std::cmp::min(*ans, (*prev - val).abs());
+        *prev = val;
+        if !right.is_none() {
+            Self::traverse(right.clone(), prev, ans);
+        }
+    }
+}