univalued-binary-tree

Author: bestgopher

README.md

@@ -25,6 +25,9 @@
 -  746：检查整数及其两倍数是否存在
 	- [src](https://github.com/rustors/leetcode/blob/main/src/bin/check-if-n-and-its-double-exist.rs) 
 	- [leetcode](https://leetcode-cn.com/problems/check-if-n-and-its-double-exist/)
+- 965：单值二叉树
+- [src](https://github.com/rustors/leetcode/blob/main/src/bin/univalued-binary-tree.rs) 
+  - [leetcode](https://leetcode-cn.com/problems/univalued-binary-tree/)
 - 1008：前序遍历构造二叉搜索树
 
 	- [src](https://github.com/rustors/leetcode/blob/main/src/bin/construct-binary-search-tree-from-preorder-traversal.rs)
@@ -39,6 +42,7 @@
 	- [src](https://github.com/rustors/leetcode/blob/main/src/bin/maximum-points-you-can-obtain-from-cards.rs)
   - [leetcode](https://leetcode-cn.com/problems/running-sum-of-1d-array/)
 -  1678：设计 Goal 解析器
-- [src](https://github.com/rustors/leetcode/blob/main/src/bin/goal-parser-interpretation.rs)
+
+  - [src](https://github.com/rustors/leetcode/blob/main/src/bin/goal-parser-interpretation.rs)
   - [leetcode](https://leetcode-cn.com/problems/goal-parser-interpretation/)
 

src/bin/univalued-binary-tree.rs

@@ -0,0 +1,61 @@
+// 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;
+
+struct Solution;
+
+impl Solution {
+    // 递归
+    pub fn is_unival_tree(root: Option<Rc<RefCell<TreeNode>>>) -> bool {
+        match root {
+            None => true,
+            Some(r) => {
+                let value = r.borrow().val;
+
+                let left_result = match &r.borrow().left {
+                    Some(left) => {
+                        if left.borrow().val != value {
+                            false
+                        } else {
+                            Solution::is_unival_tree(Some(Rc::clone(left)))
+                        }
+                    }
+                    None => true,
+                };
+
+                let right_result = match &r.borrow().right {
+                    Some(right) => {
+                        if right.borrow().val != value {
+                            false
+                        } else {
+                            Solution::is_unival_tree(Some(Rc::clone(right)))
+                        }
+                    }
+                    None => true,
+                };
+
+                left_result && right_result
+            }
+        }
+    }
+}
+
+fn main() {}