Merge pull request #1758 from Jack-Zhang-1314/patch-19

Update 0257.二叉树的所有路径.md about rust

problems/0257.二叉树的所有路径.md

@@ -794,6 +794,33 @@ object Solution {
   }
 }
 ```
+	
+rust:
+
+```rust
+// 递归
+impl Solution {
+    pub fn binary_tree_paths(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<String> {
+        let mut res = vec![];
+        Self::recur(&root, String::from(""), &mut res);
+        res
+    }
+    pub fn recur(node: &Option<Rc<RefCell<TreeNode>>>, mut path: String, res: &mut Vec<String>) {
+        let r = node.as_ref().unwrap().borrow();
+        path += format!("{}", r.val).as_str();
+        if r.left.is_none() && r.right.is_none() {
+            res.push(path.to_string());
+            return;
+        }
+        if r.left.is_some() {
+            Self::recur(&r.left, path.clone() + "->", res);
+        }
+        if r.right.is_some() {
+            Self::recur(&r.right, path + "->", res);
+        }
+    }
+}
+```
 
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