From 4838f221f3e01d6a3b8e2a4199283533746ac3fd Mon Sep 17 00:00:00 2001
From: Matej Focko <mfocko@redhat.com>
Date: Wed, 7 Sep 2022 13:24:41 +0200
Subject: [PATCH] =?UTF-8?q?problems(kt):=20add=20=E2=80=9E606.=20Construct?=
 =?UTF-8?q?=20String=20from=20Binary=20Tree=E2=80=9C?=
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Signed-off-by: Matej Focko <mfocko@redhat.com>
---
 problems/construct-string-from-binary-tree.kt | 30 +++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 problems/construct-string-from-binary-tree.kt

diff --git a/problems/construct-string-from-binary-tree.kt b/problems/construct-string-from-binary-tree.kt
new file mode 100644
index 0000000..60669c4
--- /dev/null
+++ b/problems/construct-string-from-binary-tree.kt
@@ -0,0 +1,30 @@
+/**
+ * Example:
+ * var ti = TreeNode(5)
+ * var v = ti.`val`
+ * Definition for a binary tree node.
+ * class TreeNode(var `val`: Int) {
+ *     var left: TreeNode? = null
+ *     var right: TreeNode? = null
+ * }
+ */
+class Solution {
+    fun tree2str(root: TreeNode?): String {
+        if (root == null) {
+            return ""
+        }
+
+        val value = root.`val`.toString()
+        val left = "(${tree2str(root.left)})"
+        val right = "(${tree2str(root.right)})"
+
+
+        if (left == "()" && right == "()") {
+            return value
+        } else if (right == "()") {
+            return "$value$left"
+        }
+
+        return "$value$left$right"
+    }
+}