Merge pull request #1786 from fwqaaq/patch-6

Update 0530.二叉搜索树的最小绝对差.md about rust

problems/0530.二叉搜索树的最小绝对差.md

@@ -493,6 +493,93 @@ object Solution {
 }
 ```
 
+## rust
+
+构建二叉树的有序数组:
+
+```rust
+use std::cell::RefCell;
+use std::rc::Rc;
+impl Solution {
+    pub fn get_minimum_difference(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
+        let mut vec = vec![];
+        Self::traversal(root, &mut vec);
+        let mut min = i32::MAX;
+        for i in 1..vec.len() {
+            min = min.min(vec[i] - vec[i - 1])
+        }
+        min
+    }
+    pub fn traversal(root: Option<Rc<RefCell<TreeNode>>>, v: &mut Vec<i32>) {
+        if root.is_none() {
+            return;
+        }
+        let node = root.as_ref().unwrap().borrow();
+        Self::traversal(node.left.clone(), v);
+        v.push(node.val);
+        Self::traversal(node.right.clone(), v);
+    }
+}
+```
+
+递归中解决
+
+```rust
+impl Solution {
+    pub fn get_minimum_difference(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
+        let mut pre = None;
+        let mut min = i32::MAX;
+        Self::inorder(root, &mut pre, &mut min);
+        min
+    }
+    pub fn inorder(root: Option<Rc<RefCell<TreeNode>>>, pre: &mut Option<i32>, min: &mut i32) {
+        if root.is_none() {
+            return;
+        }
+        let node = root.as_ref().unwrap().borrow();
+        Self::inorder(node.left.clone(), pre, min);
+        if let Some(pre) = pre {
+            *min = (node.val - *pre).min(*min);
+        }
+        *pre = Some(node.val);
+
+        Self::inorder(node.right.clone(), pre, min);
+    }
+}
+```
+
+迭代
+
+```rust
+impl Solution {
+    pub fn get_minimum_difference(mut root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
+        if root.is_none() {
+            return 0;
+        }
+        let mut stack = vec![];
+        let mut pre = -1;
+        let mut res = i32::MAX;
+        while root.is_some() || !stack.is_empty() {
+            while let Some(node) = root {
+                root = node.borrow().left.clone();
+                stack.push(node);
+            }
+
+            let node = stack.pop().unwrap();
+
+            if pre >= 0 {
+                res = res.min(node.borrow().val - pre);
+            }
+
+            pre = node.borrow().val;
+
+            root = node.borrow().right.clone();
+        }
+        res
+    }
+}
+```
+
 <p align="center">
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>