diff --git a/problems/0513.找树左下角的值.md b/problems/0513.找树左下角的值.md index 12c62c70..296fe478 100644 --- a/problems/0513.找树左下角的值.md +++ b/problems/0513.找树左下角的值.md @@ -546,7 +546,50 @@ func findBottomLeftValue(_ root: TreeNode?) -> Int { } ``` +## Scala +递归版本: +```scala +object Solution { + def findBottomLeftValue(root: TreeNode): Int = { + var maxLeftValue = 0 + var maxLen = Int.MinValue + // 递归方法 + def traversal(node: TreeNode, leftLen: Int): Unit = { + // 如果左右都为空并且当前深度大于最大深度,记录最左节点的值 + if (node.left == null && node.right == null && leftLen > maxLen) { + maxLen = leftLen + maxLeftValue = node.value + } + if (node.left != null) traversal(node.left, leftLen + 1) + if (node.right != null) traversal(node.right, leftLen + 1) + } + traversal(root, 0) // 调用方法 + maxLeftValue // return关键字可以省略 + } +} +``` + +层序遍历: +```scala + import scala.collection.mutable + + def findBottomLeftValue(root: TreeNode): Int = { + val queue = mutable.Queue[TreeNode]() + queue.enqueue(root) + var res = 0 // 记录每层最左侧结果 + while (!queue.isEmpty) { + val len = queue.size + for (i <- 0 until len) { + val curNode = queue.dequeue() + if (i == 0) res = curNode.value // 记录最最左侧的节点 + if (curNode.left != null) queue.enqueue(curNode.left) + if (curNode.right != null) queue.enqueue(curNode.right) + } + } + res // 最终返回结果,return关键字可以省略 + } +``` -----------------------