Update 0700.二叉搜索树中的搜索.md

problems/0700.二叉搜索树中的搜索.md

@@ -441,6 +441,29 @@ impl Solution {
 }
 ```
 
+迭代：
+
+```rust
+use std::cell::RefCell;
+use std::rc::Rc;
+use std::cmp;
+impl Solution {
+    pub fn search_bst(
+        mut root: Option<Rc<RefCell<TreeNode>>>,
+        val: i32,
+    ) -> Option<Rc<RefCell<TreeNode>>> {
+        while let Some(ref node) = root.clone() {
+            match val.cmp(&node.borrow().val) {
+                cmp::Ordering::Less => root = node.borrow().left.clone(),
+                cmp::Ordering::Equal => return root,
+                cmp::Ordering::Greater => root = node.borrow().right.clone(),
+            };
+        }
+        None
+    }
+}
+```
+
 <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"/>