Merge pull request #1811 from fwqaaq/patch-12

Update 0669.修剪二叉搜索树.md about rust

problems/0669.修剪二叉搜索树.md

@@ -473,6 +473,33 @@ object Solution {
 }
 ```
 
+## rust
+
+// 递归
+```rust
+impl Solution {
+    pub fn trim_bst(
+        root: Option<Rc<RefCell<TreeNode>>>,
+        low: i32,
+        high: i32,
+    ) -> Option<Rc<RefCell<TreeNode>>> {
+        root.as_ref()?;
+        let mut node = root.as_ref().unwrap().borrow_mut();
+        if node.val < low {
+            return Self::trim_bst(node.right.clone(), low, high);
+        }
+        if node.val > high {
+            return Self::trim_bst(node.left.clone(), low, high);
+        }
+
+        node.left = Self::trim_bst(node.left.clone(), low, high);
+        node.right = Self::trim_bst(node.right.clone(), low, high);
+        drop(node);
+        root
+    }
+}
+```
+
 
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