Update 0101.对称二叉树.md

problems/0101.对称二叉树.md

@@ -772,6 +772,34 @@ object Solution {
 }
 ```
 
+## Rust
+
+递归：
+```rust
+impl Solution {
+    pub fn is_symmetric(root: Option<Rc<RefCell<TreeNode>>>) -> bool {
+        Self::recur(
+            &root.as_ref().unwrap().borrow().left,
+            &root.as_ref().unwrap().borrow().right,
+        )
+    }
+    pub fn recur(
+        left: &Option<Rc<RefCell<TreeNode>>>,
+        right: &Option<Rc<RefCell<TreeNode>>>,
+    ) -> bool {
+        match (left, right) {
+            (None, None) => true,
+            (Some(n1), Some(n2)) => {
+                return n1.borrow().val == n2.borrow().val
+                    && Self::recur(&n1.borrow().left, &n2.borrow().right)
+                    && Self::recur(&n1.borrow().right, &n2.borrow().left)
+            }
+            _ => false,
+        }
+    }
+}
+```
+
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