maximum depth of binary tree solution

Author: yhkee0404

maximum-depth-of-binary-tree/yhkee0404.rs

@@ -0,0 +1,31 @@
+// Definition for a binary tree node.
+// #[derive(Debug, PartialEq, Eq)]
+// pub struct TreeNode {
+//   pub val: i32,
+//   pub left: Option<Rc<RefCell<TreeNode>>>,
+//   pub right: Option<Rc<RefCell<TreeNode>>>,
+// }
+// 
+// impl TreeNode {
+//   #[inline]
+//   pub fn new(val: i32) -> Self {
+//     TreeNode {
+//       val,
+//       left: None,
+//       right: None
+//     }
+//   }
+// }
+use std::rc::Rc;
+use std::cell::RefCell;
+impl Solution {
+    pub fn max_depth(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
+        match root {
+            None => 0,
+            Some(u) => {
+                let u = u.borrow();
+                1 + Self::max_depth(u.left.clone()).max(Self::max_depth(u.right.clone()))
+            }
+        }
+    }
+}