添加 0968.监控二叉树.md Scala版本

problems/0968.监控二叉树.md

@@ -544,5 +544,40 @@ int minCameraCover(struct TreeNode* root){
 }
 ```
 
+### Scala
+
+```scala
+object Solution {
+  def minCameraCover(root: TreeNode): Int = {
+    var result = 0
+    def traversal(cur: TreeNode): Int = {
+      // 空节点，该节点有覆盖
+      if (cur == null) return 2
+      var left = traversal(cur.left)
+      var right = traversal(cur.right)
+      // 情况1，左右节点都有覆盖
+      if (left == 2 && right == 2) {
+        return 0
+      }
+      // 情况2
+      if (left == 0 || right == 0) {
+        result += 1
+        return 1
+      }
+      // 情况3
+      if (left == 1 || right == 1) {
+        return 2
+      }
+      -1
+    }
+
+    if (traversal(root) == 0) {
+      result += 1
+    }
+    result
+  }
+}
+```
+
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