Merge pull request #1762 from Jack-Zhang-1314/patch-20

Update 二叉树中递归带着回溯.md about rust

problems/二叉树中递归带着回溯.md

@@ -617,6 +617,75 @@ func _binaryTreePaths3(_ root: TreeNode, res: inout [String], paths: inout [Int]
 }
 ```
 
+### Rust
+
+> 100.相同的树
+
+```rsut
+use std::cell::RefCell;
+use std::rc::Rc;
+impl Solution {
+    pub fn is_same_tree(
+        p: Option<Rc<RefCell<TreeNode>>>,
+        q: Option<Rc<RefCell<TreeNode>>>,
+    ) -> bool {
+        match (p, q) {
+            (None, None) => true,
+            (None, Some(_)) => false,
+            (Some(_), None) => false,
+            (Some(n1), Some(n2)) => {
+                if n1.borrow().val == n2.borrow().val {
+                    let right =
+                        Self::is_same_tree(n1.borrow().left.clone(), n2.borrow().left.clone());
+                    let left =
+                        Self::is_same_tree(n1.borrow().right.clone(), n2.borrow().right.clone());
+                    right && left
+                } else {
+                    false
+                }
+            }
+        }
+    }
+}
+```
+
+> 257.二叉树的不同路径
+
+```rust
+// 递归
+use std::cell::RefCell;
+use std::rc::Rc;
+impl Solution {
+    pub fn binary_tree_paths(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<String> {
+        let mut res = vec![];
+        let mut path = vec![];
+        Self::recur(&root, &mut path, &mut res);
+        res
+    }
+
+    pub fn recur(
+        root: &Option<Rc<RefCell<TreeNode>>>,
+        path: &mut Vec<String>,
+        res: &mut Vec<String>,
+    ) {
+        let node = root.as_ref().unwrap().borrow();
+        path.push(node.val.to_string());
+        if node.left.is_none() && node.right.is_none() {
+            res.push(path.join("->"));
+            return;
+        }
+        if node.left.is_some() {
+            Self::recur(&node.left, path, res);
+            path.pop(); //回溯
+        }
+        if node.right.is_some() {
+            Self::recur(&node.right, path, res);
+            path.pop(); //回溯
+        }
+    }
+}
+```
+
 
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