Merge pull request #1778 from fwqaaq/patch-3

Update 0617.合并二叉树.md about rust

problems/0617.合并二叉树.md

@@ -655,6 +655,78 @@ object Solution {
 }
 ```
 
+### rust
+
+递归：
+
+```rust
+use std::cell::RefCell;
+use std::rc::Rc;
+impl Solution {
+    pub fn merge_trees(
+        root1: Option<Rc<RefCell<TreeNode>>>,
+        root2: Option<Rc<RefCell<TreeNode>>>,
+    ) -> Option<Rc<RefCell<TreeNode>>> {
+        if root1.is_none() {
+            return root2;
+        }
+        if root2.is_none() {
+            return root1;
+        }
+        let binding = root1.clone();
+        let mut node1 = binding.as_ref().unwrap().borrow_mut();
+        let node2 = root2.as_ref().unwrap().borrow_mut();
+        node1.left = Self::merge_trees(node1.left.clone(), node2.left.clone());
+        node1.right = Self::merge_trees(node1.right.clone(), node2.right.clone());
+        node1.val += node2.val;
+
+        root1
+    }
+}
+```
+
+迭代：
+
+```rust
+impl Solution {
+    pub fn merge_trees(
+        root1: Option<Rc<RefCell<TreeNode>>>,
+        root2: Option<Rc<RefCell<TreeNode>>>,
+    ) -> Option<Rc<RefCell<TreeNode>>> {
+        if root1.is_none() {
+            return root2;
+        }
+        if root2.is_none() {
+            return root1;
+        }
+        let mut stack = vec![];
+        stack.push(root2);
+        stack.push(root1.clone());
+        while !stack.is_empty() {
+            let node1 = stack.pop().unwrap().unwrap();
+            let node2 = stack.pop().unwrap().unwrap();
+            let mut node1 = node1.borrow_mut();
+            let node2 = node2.borrow();
+            node1.val += node2.val;
+            if node1.left.is_some() && node2.left.is_some() {
+                stack.push(node2.left.clone());
+                stack.push(node1.left.clone());
+            }
+            if node1.right.is_some() && node2.right.is_some() {
+                stack.push(node2.right.clone());
+                stack.push(node1.right.clone());
+            }
+            if node1.left.is_none() && node2.left.is_some() {
+                node1.left = node2.left.clone();
+            }
+            if node1.right.is_none() && node2.right.is_some() {
+                node1.right = node2.right.clone();
+            }
+        }
+        root1
+    }
+}
+```
 
 <p align="center">
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">