rust 968 min camera cover

problems/0968.监控二叉树.md

@@ -579,6 +579,55 @@ object Solution {
 }
 ```
 
+```Rust
+/// 版本一
+impl Solution {
+    pub fn min_camera_cover(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
+        let mut res = 0;
+        if Self::traversal(&root, &mut res) == 0 {
+            res += 1;
+        }
+        res
+    }
+
+    pub fn traversal(cur: &Option<Rc<RefCell<TreeNode>>>, ans: &mut i32) -> i32 {
+        // 0 未覆盖 1 节点已设置摄像头 2 节点已覆盖
+        if let Some(node) = cur {
+            let node = node.borrow();
+
+            let left = Self::traversal(&node.left, ans);
+            let right = Self::traversal(&node.right, ans);
+
+            // 左右节点都被覆盖
+            if left == 2 && right == 2 {
+                return 0; // 无覆盖
+            }
+
+            // left == 0 right == 0 左右无覆盖
+            // left == 0 right == 1 左节点无覆盖 右节点有摄像头
+            // left == 1 right == 0 左节点有摄像头 左节点无覆盖
+            // left == 0 right == 2 左节点无覆盖 右节点有覆盖
+            // left == 2 right == 0 左节点有覆盖 右节点无覆盖
+            if left == 0 || right == 0 {
+                *ans += 1;
+                return 1;
+            }
+
+            // left == 1 right == 1 左节点有摄像头 右节点有摄像头
+            // left == 1 right == 2 左节点有摄像头 右节点覆盖
+            // left == 2 right == 1 左节点覆盖 右节点有摄像头
+            if left == 1 || right == 1 {
+                return 2; // 已覆盖
+            }
+        } else {
+            return 2;
+        }
+        -1
+    }
+}
+
+```
+
 <p align="center">
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>