添加 429.N叉树的层序遍历 Scala版本

problems/0102.二叉树的层序遍历.md

@@ -1274,6 +1274,34 @@ func levelOrder(_ root: Node?) -> [[Int]] {
 }
 ```
 
+Scala:
+```scala
+// 429.N叉树的层序遍历
+object Solution {
+  import scala.collection.mutable
+  def levelOrder(root: Node): List[List[Int]] = {
+    val res = mutable.ListBuffer[List[Int]]()
+    if (root == null) return res.toList
+    val queue = mutable.Queue[Node]()
+    queue.enqueue(root) // 根节点入队
+    while (!queue.isEmpty) {
+      val tmp = mutable.ListBuffer[Int]() // 存储每层节点
+      val len = queue.size
+      for (i <- 0 until len) {
+        val curNode = queue.dequeue()
+        tmp.append(curNode.value) // 将该节点的值加入tmp
+        // 循环遍历该节点的子节点，加入队列
+        for (child <- curNode.children) {
+          queue.enqueue(child)
+        }
+      }
+      res.append(tmp.toList) // 将该层的节点放到结果集
+    }
+    res.toList
+  }
+}
+```
+
 # 515.在每个树行中找最大值
 
 [力扣题目链接](https://leetcode-cn.com/problems/find-largest-value-in-each-tree-row/)