Merge pull request #1353 from wzqwtt/tree04

添加（515.在每个树行中找最大值、116.填充每个节点的下一个右侧节点指针、117.填充每个节点的下一个右侧节点指针II）Scala版本

problems/0102.二叉树的层序遍历.md

@@ -1640,6 +1640,32 @@ func largestValues(_ root: TreeNode?) -> [Int] {
 }
 ```
 
+Scala:
+```scala
+// 515.在每个树行中找最大值
+object Solution {
+  import scala.collection.mutable
+  def largestValues(root: TreeNode): List[Int] = {
+    val res = mutable.ListBuffer[Int]()
+    if (root == null) return res.toList
+    val queue = mutable.Queue[TreeNode]()
+    queue.enqueue(root)
+    while (!queue.isEmpty) {
+      var max = Int.MinValue // 初始化max为系统最小值
+      val len = queue.size
+      for (i <- 0 until len) {
+        val curNode = queue.dequeue()
+        max = math.max(max, curNode.value) // 对比求解最大值
+        if (curNode.left != null) queue.enqueue(curNode.left)
+        if (curNode.right != null) queue.enqueue(curNode.right)
+      }
+      res.append(max) // 将最大值放入结果集
+    }
+    res.toList
+  }
+}
+```
+
 # 116.填充每个节点的下一个右侧节点指针
 
 [力扣题目链接](https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node/)
@@ -1899,6 +1925,35 @@ func connect(_ root: Node?) -> Node? {
 }
 ```
 
+Scala:
+```scala
+// 116.填充每个节点的下一个右侧节点指针
+object Solution {
+  import scala.collection.mutable
+
+  def connect(root: Node): Node = {
+    if (root == null) return root
+    val queue = mutable.Queue[Node]()
+    queue.enqueue(root)
+    while (!queue.isEmpty) {
+      val len = queue.size
+      val tmp = mutable.ListBuffer[Node]()
+      for (i <- 0 until len) {
+        val curNode = queue.dequeue()
+        tmp.append(curNode)
+        if (curNode.left != null) queue.enqueue(curNode.left)
+        if (curNode.right != null) queue.enqueue(curNode.right)
+      }
+      // 处理next指针
+      for (i <- 0 until tmp.size - 1) {
+        tmp(i).next = tmp(i + 1)
+      }
+      tmp(tmp.size-1).next = null
+    }
+    root
+  }
+}
+```
 # 117.填充每个节点的下一个右侧节点指针II
 
 [力扣题目链接](https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node-ii/)
@@ -2150,6 +2205,35 @@ func connect(_ root: Node?) -> Node? {
 }
 ```
 
+Scala:
+```scala
+// 117.填充每个节点的下一个右侧节点指针II
+object Solution {
+  import scala.collection.mutable
+
+  def connect(root: Node): Node = {
+    if (root == null) return root
+    val queue = mutable.Queue[Node]()
+    queue.enqueue(root)
+    while (!queue.isEmpty) {
+      val len = queue.size
+      val tmp = mutable.ListBuffer[Node]()
+      for (i <- 0 until len) {
+        val curNode = queue.dequeue()
+        tmp.append(curNode)
+        if (curNode.left != null) queue.enqueue(curNode.left)
+        if (curNode.right != null) queue.enqueue(curNode.right)
+      }
+      // 处理next指针
+      for (i <- 0 until tmp.size - 1) {
+        tmp(i).next = tmp(i + 1)
+      }
+      tmp(tmp.size-1).next = null
+    }
+    root
+  }
+}
+```
 # 104.二叉树的最大深度
 
 [力扣题目链接](https://leetcode-cn.com/problems/maximum-depth-of-binary-tree/)